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From: shivram@apache.org
To: commits@hawq.incubator.apache.org
Date: Wed, 28 Oct 2015 22:09:53 -0000
Message-Id: <74ef18761f724c06b60dd8995cab74bc@git.apache.org>
In-Reply-To: <2a46fd82f3074b87af97f1eb7c663e5e@git.apache.org>
References: <2a46fd82f3074b87af97f1eb7c663e5e@git.apache.org>
Subject: [03/15] incubator-hawq git commit: HAWQ-45. PXF Package Namespace
 change

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeInputBuilder.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeInputBuilder.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeInputBuilder.java
new file mode 100644
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+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.OneField;
+import org.apache.hawq.pxf.api.OutputFormat;
+import org.apache.hawq.pxf.api.io.DataType;
+import org.apache.hawq.pxf.service.io.GPDBWritable;
+import org.apache.hawq.pxf.service.io.Text;
+import org.apache.hawq.pxf.service.utilities.ProtocolData;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.DataInput;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+public class BridgeInputBuilder {
+    private ProtocolData protocolData;
+    private static final Log LOG = LogFactory.getLog(BridgeInputBuilder.class);
+
+    public BridgeInputBuilder(ProtocolData protocolData) throws Exception {
+        this.protocolData = protocolData;
+    }
+
+    public List<OneField> makeInput(DataInput inputStream) throws Exception {
+        if (protocolData.outputFormat() == OutputFormat.TEXT) {
+            Text txt = new Text();
+            txt.readFields(inputStream);
+            return Collections.singletonList(new OneField(DataType.BYTEA.getOID(), txt.getBytes()));
+        }
+
+        GPDBWritable gpdbWritable = new GPDBWritable();
+        gpdbWritable.readFields(inputStream);
+
+        if (gpdbWritable.isEmpty()) {
+            LOG.debug("Reached end of stream");
+            return null;
+        }
+
+        GPDBWritableMapper mapper = new GPDBWritableMapper(gpdbWritable);
+        int[] colTypes = gpdbWritable.getColType();
+        List<OneField> record = new LinkedList<OneField>();
+        for (int i = 0; i < colTypes.length; i++) {
+            mapper.setDataType(colTypes[i]);
+            record.add(new OneField(colTypes[i], mapper.getData(i)));
+        }
+
+        return record;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeOutputBuilder.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeOutputBuilder.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeOutputBuilder.java
new file mode 100644
index 0000000..99255fa
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/BridgeOutputBuilder.java
@@ -0,0 +1,288 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.BadRecordException;
+import org.apache.hawq.pxf.api.OneField;
+import org.apache.hawq.pxf.api.OutputFormat;
+import org.apache.hawq.pxf.api.io.DataType;
+import org.apache.hawq.pxf.service.io.BufferWritable;
+import org.apache.hawq.pxf.service.io.GPDBWritable;
+import org.apache.hawq.pxf.service.io.GPDBWritable.TypeMismatchException;
+import org.apache.hawq.pxf.service.io.Text;
+import org.apache.hawq.pxf.service.io.Writable;
+import org.apache.hawq.pxf.service.utilities.ProtocolData;
+import org.apache.commons.lang.ObjectUtils;
+
+import java.lang.reflect.Array;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.apache.hawq.pxf.api.io.DataType.TEXT;
+
+/**
+ * Class creates the output record that is piped by the java process to the HAWQ
+ * backend. Actually, the output record is serialized and the obtained byte
+ * string is piped to the HAWQ segment. The output record will implement
+ * Writable, and the mission of BridgeOutputBuilder will be to translate a list
+ * of {@link OneField} objects (obtained from the Resolver) into an output
+ * record.
+ */
+public class BridgeOutputBuilder {
+    private ProtocolData inputData;
+    private Writable output = null;
+    private GPDBWritable errorRecord = null;
+    private int[] schema;
+    private String[] colNames;
+
+    /**
+     * Constructs a BridgeOutputBuilder.
+     *
+     * @param input input data, like requested output format and schema
+     *            information
+     */
+    public BridgeOutputBuilder(ProtocolData input) {
+        inputData = input;
+        makeErrorRecord();
+    }
+
+    /**
+     * We need a separate GPDBWritable record to represent the error record.
+     * Just setting the errorFlag on the "output" GPDBWritable variable is not
+     * good enough, since the GPDBWritable is built only after the first record
+     * is read from the file. And if we encounter an error while fetching the
+     * first record from the file, then the output member will be null. The
+     * reason we cannot count on the schema to build the GPDBWritable output
+     * variable before reading the first record, is because the schema does not
+     * account for arrays - we cannot know from the schema the length of an
+     * array. We find out only after fetching the first record.
+     */
+    void makeErrorRecord() {
+        int[] errSchema = { TEXT.getOID() };
+
+        if (inputData.outputFormat() != OutputFormat.BINARY) {
+            return;
+        }
+
+        errorRecord = new GPDBWritable(errSchema);
+        errorRecord.setError(true);
+    }
+
+    /**
+     * Returns the error record. If the output format is not binary, error
+     * records are not supported, and the given exception will be thrown
+     *
+     * @param ex exception to be stored in record
+     * @return error record
+     * @throws Exception if the output format is not binary
+     */
+    public Writable getErrorOutput(Exception ex) throws Exception {
+        if (inputData.outputFormat() == OutputFormat.BINARY) {
+            errorRecord.setString(0, ex.getMessage());
+            return errorRecord;
+        } else {
+            throw ex;
+        }
+    }
+
+    /**
+     * Translates recFields (obtained from the Resolver) into an output record.
+     *
+     * @param recFields record fields to be serialized
+     * @return Writable object with serialized row
+     * @throws BadRecordException if building the output record failed
+     */
+    public Writable makeOutput(List<OneField> recFields)
+            throws BadRecordException {
+        if (output == null && inputData.outputFormat() == OutputFormat.BINARY) {
+            makeGPDBWritableOutput();
+        }
+
+        fillOutputRecord(recFields);
+
+        return output;
+    }
+
+    /**
+     * Creates the GPDBWritable object. The object is created one time and is
+     * refilled from recFields for each record sent
+     *
+     * @return empty GPDBWritable object with set columns
+     */
+    GPDBWritable makeGPDBWritableOutput() {
+        int num_actual_fields = inputData.getColumns();
+        schema = new int[num_actual_fields];
+        colNames = new String[num_actual_fields];
+
+        for (int i = 0; i < num_actual_fields; i++) {
+            schema[i] = inputData.getColumn(i).columnTypeCode();
+            colNames[i] = inputData.getColumn(i).columnName();
+        }
+
+        output = new GPDBWritable(schema);
+
+        return (GPDBWritable) output;
+    }
+
+    /**
+     * Fills the output record based on the fields in recFields.
+     *
+     * @param recFields record fields
+     * @throws BadRecordException if building the output record failed
+     */
+    void fillOutputRecord(List<OneField> recFields) throws BadRecordException {
+        if (inputData.outputFormat() == OutputFormat.BINARY) {
+            fillGPDBWritable(recFields);
+        } else {
+            fillText(recFields);
+        }
+    }
+
+    /**
+     * Fills a GPDBWritable object based on recFields. The input record
+     * recFields must correspond to schema. If the record has more or less
+     * fields than the schema we throw an exception. We require that the type of
+     * field[i] in recFields corresponds to the type of field[i] in the schema.
+     *
+     * @param recFields record fields
+     * @throws BadRecordException if building the output record failed
+     */
+    void fillGPDBWritable(List<OneField> recFields) throws BadRecordException {
+        int size = recFields.size();
+        if (size == 0) { // size 0 means the resolver couldn't deserialize any
+                         // of the record fields
+            throw new BadRecordException("No fields in record");
+        } else if (size != schema.length) {
+            throw new BadRecordException("Record has " + size
+                    + " fields but the schema size is " + schema.length);
+        }
+
+        for (int i = 0; i < size; i++) {
+            OneField current = recFields.get(i);
+            if (!isTypeInSchema(current.type, schema[i])) {
+                throw new BadRecordException("For field " + colNames[i]
+                        + " schema requires type "
+                        + DataType.get(schema[i]).toString()
+                        + " but input record has type "
+                        + DataType.get(current.type).toString());
+            }
+
+            fillOneGPDBWritableField(current, i);
+        }
+    }
+
+    /**
+     * Tests if data type is a string type. String type is a type that can be
+     * serialized as string, such as varchar, bpchar, text, numeric, timestamp,
+     * date.
+     *
+     * @param type data type
+     * @return whether data type is string type
+     */
+    boolean isStringType(DataType type) {
+        return Arrays.asList(DataType.VARCHAR, DataType.BPCHAR, DataType.TEXT,
+                DataType.NUMERIC, DataType.TIMESTAMP, DataType.DATE).contains(
+                type);
+    }
+
+    /**
+     * Tests if record field type and schema type correspond.
+     *
+     * @param recType record type code
+     * @param schemaType schema type code
+     * @return whether record type and schema type match
+     */
+    boolean isTypeInSchema(int recType, int schemaType) {
+        DataType dtRec = DataType.get(recType);
+        DataType dtSchema = DataType.get(schemaType);
+
+        return (dtSchema == DataType.UNSUPPORTED_TYPE || dtRec == dtSchema || (isStringType(dtRec) && isStringType(dtSchema)));
+    }
+
+    /**
+     * Fills a Text object based on recFields.
+     *
+     * @param recFields record fields
+     * @throws BadRecordException if text formatted record has more than one field
+     */
+    void fillText(List<OneField> recFields) throws BadRecordException {
+        /*
+         * For the TEXT case there must be only one record in the list
+         */
+        if (recFields.size() != 1) {
+            throw new BadRecordException(
+                    "BridgeOutputBuilder must receive one field when handling the TEXT format");
+        }
+
+        OneField fld = recFields.get(0);
+        int type = fld.type;
+        Object val = fld.val;
+        if (DataType.get(type) == DataType.BYTEA) {// from LineBreakAccessor
+            output = new BufferWritable((byte[]) val);
+        } else { // from QuotedLineBreakAccessor
+            String textRec = (String) val;
+            output = new Text(textRec + "\n");
+        }
+    }
+
+    /**
+     * Fills one GPDBWritable field.
+     *
+     * @param oneField field
+     * @param colIdx column index
+     * @throws BadRecordException if field type is not supported or doesn't match the schema
+     */
+    void fillOneGPDBWritableField(OneField oneField, int colIdx)
+            throws BadRecordException {
+        int type = oneField.type;
+        Object val = oneField.val;
+        GPDBWritable GPDBoutput = (GPDBWritable) output;
+        try {
+            switch (DataType.get(type)) {
+                case INTEGER:
+                    GPDBoutput.setInt(colIdx, (Integer) val);
+                    break;
+                case FLOAT8:
+                    GPDBoutput.setDouble(colIdx, (Double) val);
+                    break;
+                case REAL:
+                    GPDBoutput.setFloat(colIdx, (Float) val);
+                    break;
+                case BIGINT:
+                    GPDBoutput.setLong(colIdx, (Long) val);
+                    break;
+                case SMALLINT:
+                    GPDBoutput.setShort(colIdx, (Short) val);
+                    break;
+                case BOOLEAN:
+                    GPDBoutput.setBoolean(colIdx, (Boolean) val);
+                    break;
+                case BYTEA:
+                    byte[] bts = null;
+                    if (val != null) {
+                        int length = Array.getLength(val);
+                        bts = new byte[length];
+                        for (int j = 0; j < length; j++) {
+                            bts[j] = Array.getByte(val, j);
+                        }
+                    }
+                    GPDBoutput.setBytes(colIdx, bts);
+                    break;
+                case VARCHAR:
+                case BPCHAR:
+                case CHAR:
+                case TEXT:
+                case NUMERIC:
+                case TIMESTAMP:
+                case DATE:
+                    GPDBoutput.setString(colIdx, ObjectUtils.toString(val, null));
+                    break;
+                default:
+                    String valClassName = (val != null) ? val.getClass().getSimpleName()
+                            : null;
+                    throw new UnsupportedOperationException(valClassName
+                            + " is not supported for HAWQ conversion");
+            }
+        } catch (TypeMismatchException e) {
+            throw new BadRecordException(e);
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmenterFactory.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmenterFactory.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmenterFactory.java
new file mode 100644
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+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmenterFactory.java
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+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.Fragmenter;
+import org.apache.hawq.pxf.api.utilities.InputData;
+import org.apache.hawq.pxf.service.utilities.Utilities;
+
+/**
+ * Factory class for creation of {@link Fragmenter} objects. The actual {@link Fragmenter} object is "hidden" behind
+ * an {@link Fragmenter} abstract class which is returned by the FragmenterFactory. 
+ */
+public class FragmenterFactory {
+    static public Fragmenter create(InputData inputData) throws Exception {
+    	String fragmenterName = inputData.getFragmenter();
+    	
+        return (Fragmenter) Utilities.createAnyInstance(InputData.class, fragmenterName, inputData);
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponse.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponse.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponse.java
new file mode 100644
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+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponse.java
@@ -0,0 +1,63 @@
+package org.apache.hawq.pxf.service;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.List;
+
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.StreamingOutput;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.codehaus.jackson.map.ObjectMapper;
+
+import org.apache.hawq.pxf.api.Fragment;
+
+/**
+ * Class for serializing fragments metadata in JSON format.
+ * The class implements {@link StreamingOutput} so the serialization will be
+ * done in a stream and not in one bulk, this in order to avoid running
+ * out of memory when processing a lot of fragments.
+ */
+public class FragmentsResponse implements StreamingOutput {
+
+    private static Log Log = LogFactory.getLog(FragmentsResponse.class);
+
+    private List<Fragment> fragments;
+
+    /**
+     * Constructs fragments response out of a list of fragments
+     *
+     * @param fragments fragment list
+     */
+    public FragmentsResponse(List<Fragment> fragments) {
+        this.fragments = fragments;
+    }
+
+    /**
+     * Serializes a fragments list in JSON,
+     * To be used as the result string for HAWQ.
+     * An example result is as follows:
+     * {@code {"PXFFragments":[{"replicas":["sdw1.corp.emc.com","sdw3.corp.emc.com","sdw8.corp.emc.com"],"sourceName":"text2.csv", "index":"0", "metadata":<base64 metadata for fragment>, "userData":"<data_specific_to_third_party_fragmenter>"},{"replicas":["sdw2.corp.emc.com","sdw4.corp.emc.com","sdw5.corp.emc.com"],"sourceName":"text_data.csv","index":"0","metadata":<base64 metadata for fragment>,"userData":"<data_specific_to_third_party_fragmenter>"}]}}
+     */
+    @Override
+    public void write(OutputStream output) throws IOException,
+            WebApplicationException {
+        DataOutputStream dos = new DataOutputStream(output);
+        ObjectMapper mapper = new ObjectMapper();
+
+        dos.write("{\"PXFFragments\":[".getBytes());
+
+        String prefix = "";
+        for (Fragment fragment : fragments) {
+            StringBuilder result = new StringBuilder();
+            /* metaData and userData are automatically converted to Base64 */
+            result.append(prefix).append(mapper.writeValueAsString(fragment));
+            prefix = ",";
+            dos.write(result.toString().getBytes());
+        }
+
+        dos.write("]}".getBytes());
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponseFormatter.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponseFormatter.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponseFormatter.java
new file mode 100644
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+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/FragmentsResponseFormatter.java
@@ -0,0 +1,135 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.Fragment;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.HashMap;
+import java.util.List;
+
+/**
+ * Utility class for converting Fragments into a {@link FragmentsResponse}
+ * that will serialize them into JSON format.
+ */
+public class FragmentsResponseFormatter {
+
+    private static Log LOG = LogFactory.getLog(FragmentsResponseFormatter.class);
+
+    /**
+     * Converts Fragments list to FragmentsResponse
+     * after replacing host name by their respective IPs.
+     *
+     * @param fragments list of fragments
+     * @param data data (e.g. path) related to the fragments
+     * @return FragmentsResponse with given fragments
+     * @throws UnknownHostException if converting host names to IP fails
+     */
+    public static FragmentsResponse formatResponse(List<Fragment> fragments, String data) throws UnknownHostException   {
+        /* print the raw fragment list to log when in debug level */
+        if (LOG.isDebugEnabled()) {
+            LOG.debug("Fragments before conversion to IP list:");
+            FragmentsResponseFormatter.printList(fragments, data);
+        }
+
+        /* HD-2550: convert host names to IPs */
+        convertHostsToIPs(fragments);
+
+        updateFragmentIndex(fragments);
+
+	/* print the fragment list to log when in debug level */
+        if (LOG.isDebugEnabled()) {
+            FragmentsResponseFormatter.printList(fragments, data);
+        }
+
+        return new FragmentsResponse(fragments);
+    }
+
+    /**
+     * Updates the fragments' indexes so that it is incremented by sourceName.
+     * (E.g.: {"a", 0}, {"a", 1}, {"b", 0} ... )
+     *
+     * @param fragments fragments to be updated
+     */
+    private static void updateFragmentIndex(List<Fragment> fragments) {
+
+        String sourceName = null;
+        int index = 0;
+        for (Fragment fragment : fragments) {
+
+            String currentSourceName = fragment.getSourceName();
+            if (!currentSourceName.equals(sourceName)) {
+                index = 0;
+                sourceName = currentSourceName;
+            }
+            fragment.setIndex(index++);
+        }
+    }
+
+    /**
+     * Converts hosts to their matching IP addresses.
+     *
+     * @throws UnknownHostException if converting host name to IP fails
+     */
+    private static void convertHostsToIPs(List<Fragment> fragments) throws UnknownHostException {
+        /* host converted to IP map. Used to limit network calls. */
+        HashMap<String, String> hostToIpMap = new HashMap<String, String>();
+
+        for (Fragment fragment : fragments) {
+            String[] hosts = fragment.getReplicas();
+            if (hosts == null) {
+                continue;
+            }
+            String[] ips = new String[hosts.length];
+            int index = 0;
+
+            for (String host : hosts) {
+                String convertedIp = hostToIpMap.get(host);
+                if (convertedIp == null) {
+                    /* find host's IP, and add to map */
+                    InetAddress addr = InetAddress.getByName(host);
+                    convertedIp = addr.getHostAddress();
+                    hostToIpMap.put(host, convertedIp);
+                }
+
+                /* update IPs array */
+                ips[index] = convertedIp;
+                ++index;
+            }
+            fragment.setReplicas(ips);
+        }
+    }
+
+    /*
+     * Converts a fragments list to a readable string and prints it to the log.
+     * Intended for debugging purposes only.
+     * 'datapath' is the data path part of the original URI (e.g., table name, *.csv, etc).
+	 */
+    private static void printList(List<Fragment> fragments, String datapath) {
+        LOG.debug("List of " +
+                (fragments.isEmpty() ? "no" : fragments.size()) + "fragments for \"" +
+                 datapath + "\"");
+
+        int i = 0;
+        for (Fragment fragment : fragments) {
+            StringBuilder result = new StringBuilder();
+            result.append("Fragment #").append(++i).append(": [")
+                .append("Source: ").append(fragment.getSourceName())
+                .append(", Index: ").append(fragment.getIndex())
+                .append(", Replicas:");
+            for (String host : fragment.getReplicas()) {
+                result.append(" ").append(host);
+            }
+
+            result.append(", Metadata: ").append(new String(fragment.getMetadata()));
+
+            if (fragment.getUserData() != null) {
+                result.append(", User Data: ").append(new String(fragment.getUserData()));
+            }
+            result.append("] ");
+            LOG.debug(result);
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/GPDBWritableMapper.java
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diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/GPDBWritableMapper.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/GPDBWritableMapper.java
new file mode 100644
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+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/GPDBWritableMapper.java
@@ -0,0 +1,115 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.UnsupportedTypeException;
+import org.apache.hawq.pxf.api.io.DataType;
+import org.apache.hawq.pxf.service.io.GPDBWritable;
+import org.apache.hawq.pxf.service.io.GPDBWritable.TypeMismatchException;
+
+/*
+ * Class for mapping GPDBWritable get functions to java types.
+ */
+public class GPDBWritableMapper {
+
+    private GPDBWritable gpdbWritable;
+    private int type;
+    private DataGetter getter = null;
+
+    public GPDBWritableMapper(GPDBWritable gpdbWritable) {
+        this.gpdbWritable = gpdbWritable;
+    }
+
+    public void setDataType(int type) throws UnsupportedTypeException {
+        this.type = type;
+
+        switch (DataType.get(type)) {
+            case BOOLEAN:
+                getter = new BooleanDataGetter();
+                break;
+            case BYTEA:
+                getter = new BytesDataGetter();
+                break;
+            case BIGINT:
+                getter = new LongDataGetter();
+                break;
+            case SMALLINT:
+                getter = new ShortDataGetter();
+                break;
+            case INTEGER:
+                getter = new IntDataGetter();
+                break;
+            case TEXT:
+                getter = new StringDataGetter();
+                break;
+            case REAL:
+                getter = new FloatDataGetter();
+                break;
+            case FLOAT8:
+                getter = new DoubleDataGetter();
+                break;
+            default:
+                throw new UnsupportedTypeException(
+                        "Type " + GPDBWritable.getTypeName(type) +
+                                " is not supported by GPDBWritable");
+        }
+    }
+
+    public Object getData(int colIdx) throws TypeMismatchException {
+        return getter.getData(colIdx);
+    }
+
+    private interface DataGetter {
+        abstract Object getData(int colIdx) throws TypeMismatchException;
+    }
+
+    private class BooleanDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getBoolean(colIdx);
+        }
+    }
+
+    private class BytesDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getBytes(colIdx);
+        }
+    }
+
+    private class DoubleDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getDouble(colIdx);
+        }
+    }
+
+    private class FloatDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getFloat(colIdx);
+        }
+    }
+
+    private class IntDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getInt(colIdx);
+        }
+    }
+
+    private class LongDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getLong(colIdx);
+        }
+    }
+
+    private class ShortDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getShort(colIdx);
+        }
+    }
+
+    private class StringDataGetter implements DataGetter {
+        public Object getData(int colIdx) throws TypeMismatchException {
+            return gpdbWritable.getString(colIdx);
+        }
+    }
+
+    public String toString() {
+        return "getter type = " + GPDBWritable.getTypeName(type);
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataFetcherFactory.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataFetcherFactory.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataFetcherFactory.java
new file mode 100644
index 0000000..cfd1105
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataFetcherFactory.java
@@ -0,0 +1,14 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.MetadataFetcher;
+
+/**
+ * Factory class for creation of {@link MetadataFetcher} objects. 
+ * The actual {@link MetadataFetcher} object is "hidden" behind an {@link MetadataFetcher} 
+ * abstract class which is returned by the MetadataFetcherFactory. 
+ */
+public class MetadataFetcherFactory {
+    static public MetadataFetcher create(String fetcherName) throws Exception {
+        return (MetadataFetcher) Class.forName(fetcherName).newInstance();
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataResponseFormatter.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataResponseFormatter.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataResponseFormatter.java
new file mode 100644
index 0000000..6f33f2a
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/MetadataResponseFormatter.java
@@ -0,0 +1,86 @@
+package org.apache.hawq.pxf.service;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
+
+import org.apache.hawq.pxf.api.Metadata;
+
+/**
+ * Utility class for converting {@link Metadata} into a JSON format.
+ */
+public class MetadataResponseFormatter {
+
+    private static Log Log = LogFactory.getLog(MetadataResponseFormatter.class);
+
+    /**
+     * Converts {@link Metadata} to JSON String format.
+     *
+     * @param metadata metadata to convert
+     * @return JSON formatted response
+     * @throws IOException if converting the data to JSON fails
+     */
+    public static String formatResponseString(Metadata metadata) throws IOException {
+        /* print the metadata before serialization */
+        Log.debug(MetadataResponseFormatter.metadataToString(metadata));
+
+        return MetadataResponseFormatter.metadataToJSON(metadata);
+    }
+
+    /**
+     * Serializes a metadata in JSON,
+     * To be used as the result string for HAWQ.
+     * An example result is as follows:
+     *
+     * {"PXFMetadata":[{"table":{"dbName":"default","tableName":"t1"},"fields":[{"name":"a","type":"int"},{"name":"b","type":"float"}]}]}
+     */
+    private static String metadataToJSON(Metadata metadata) throws IOException {
+
+        if (metadata == null) {
+            throw new IllegalArgumentException("metadata object is null - cannot serialize");
+        }
+
+        if ((metadata.getFields() == null) || metadata.getFields().isEmpty()) {
+            throw new IllegalArgumentException("metadata contains no fields - cannot serialize");
+        }
+
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.setSerializationInclusion(Inclusion.NON_EMPTY); // ignore empty fields
+
+        StringBuilder result = new StringBuilder("{\"PXFMetadata\":");
+        String prefix = "["; // preparation for supporting multiple tables
+        result.append(prefix).append(mapper.writeValueAsString(metadata));
+        return result.append("]}").toString();
+    }
+
+    /**
+     * Converts metadata to a readable string.
+     * Intended for debugging purposes only.
+     */
+    private static String metadataToString(Metadata metadata) {
+        StringBuilder result = new StringBuilder("Metadata for table \"");
+
+        if (metadata == null) {
+            return "No metadata";
+        }
+
+        result.append(metadata.getTable()).append("\": ");
+
+        if ((metadata.getFields() == null) || metadata.getFields().isEmpty()) {
+            result.append("no fields in table");
+            return result.toString();
+        }
+
+        int i = 0;
+        for (Metadata.Field field: metadata.getFields()) {
+            result.append("Field #").append(++i).append(": [")
+                .append("Name: ").append(field.getName())
+                .append(", Type: ").append(field.getType()).append("] ");
+        }
+
+        return result.toString();
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/ReadBridge.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/ReadBridge.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/ReadBridge.java
new file mode 100644
index 0000000..9497c6c
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/ReadBridge.java
@@ -0,0 +1,128 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.BadRecordException;
+import org.apache.hawq.pxf.api.OneRow;
+import org.apache.hawq.pxf.api.ReadAccessor;
+import org.apache.hawq.pxf.api.ReadResolver;
+import org.apache.hawq.pxf.api.utilities.InputData;
+import org.apache.hawq.pxf.api.utilities.Plugin;
+import org.apache.hawq.pxf.service.io.Writable;
+import org.apache.hawq.pxf.service.utilities.ProtocolData;
+import org.apache.hawq.pxf.service.utilities.Utilities;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.*;
+import java.nio.charset.CharacterCodingException;
+import java.util.zip.ZipException;
+
+/*
+ * ReadBridge class creates appropriate accessor and resolver.
+ * It will then create the correct output conversion
+ * class (e.g. Text or GPDBWritable) and get records from accessor,
+ * let resolver deserialize them and reserialize them using the
+ * output conversion class.
+ *
+ * The class handles BadRecordException and other exception type
+ * and marks the record as invalid for GPDB.
+ */
+public class ReadBridge implements Bridge {
+    ReadAccessor fileAccessor = null;
+    ReadResolver fieldsResolver = null;
+    BridgeOutputBuilder outputBuilder = null;
+
+    private Log Log;
+
+    /*
+     * C'tor - set the implementation of the bridge
+     */
+    public ReadBridge(ProtocolData protData) throws Exception {
+        outputBuilder = new BridgeOutputBuilder(protData);
+        Log = LogFactory.getLog(ReadBridge.class);
+        fileAccessor = getFileAccessor(protData);
+        fieldsResolver = getFieldsResolver(protData);
+    }
+
+    /*
+     * Accesses the underlying HDFS file
+     */
+    @Override
+    public boolean beginIteration() throws Exception {
+        return fileAccessor.openForRead();
+    }
+
+    /*
+     * Fetch next object from file and turn it into a record that the GPDB backend can process
+     */
+    @Override
+    public Writable getNext() throws Exception {
+        Writable output;
+        OneRow onerow = null;
+        try {
+            onerow = fileAccessor.readNextObject();
+            if (onerow == null) {
+                fileAccessor.closeForRead();
+                return null;
+            }
+
+            output = outputBuilder.makeOutput(fieldsResolver.getFields(onerow));
+        } catch (IOException ex) {
+            if (!isDataException(ex)) {
+                fileAccessor.closeForRead();
+                throw ex;
+            }
+            output = outputBuilder.getErrorOutput(ex);
+        } catch (BadRecordException ex) {
+            String row_info = "null";
+            if (onerow != null) {
+                row_info = onerow.toString();
+            }
+            if (ex.getCause() != null) {
+                Log.debug("BadRecordException " + ex.getCause().toString() + ": " + row_info);
+            } else {
+                Log.debug(ex.toString() + ": " + row_info);
+            }
+            output = outputBuilder.getErrorOutput(ex);
+        } catch (Exception ex) {
+            fileAccessor.closeForRead();
+            throw ex;
+        }
+
+        return output;
+    }
+
+    public static ReadAccessor getFileAccessor(InputData inputData) throws Exception {
+        return (ReadAccessor) Utilities.createAnyInstance(InputData.class, inputData.getAccessor(), inputData);
+    }
+
+    public static ReadResolver getFieldsResolver(InputData inputData) throws Exception {
+        return (ReadResolver) Utilities.createAnyInstance(InputData.class, inputData.getResolver(), inputData);
+    }
+
+    /*
+     * There are many exceptions that inherit IOException. Some of them like EOFException are generated
+     * due to a data problem, and not because of an IO/connection problem as the father IOException
+     * might lead us to believe. For example, an EOFException will be thrown while fetching a record
+     * from a sequence file, if there is a formatting problem in the record. Fetching record from
+     * the sequence-file is the responsibility of the accessor so the exception will be thrown from the
+     * accessor. We identify this cases by analyzing the exception type, and when we discover that the
+     * actual problem was a data problem, we return the errorOutput GPDBWritable.
+     */
+    private boolean isDataException(IOException ex) {
+        return (ex instanceof EOFException || ex instanceof CharacterCodingException ||
+                ex instanceof CharConversionException || ex instanceof UTFDataFormatException ||
+                ex instanceof ZipException);
+    }
+
+    @Override
+    public boolean setNext(DataInputStream inputStream) {
+        throw new UnsupportedOperationException("setNext is not implemented");
+    }
+
+    @Override
+    public boolean isThreadSafe() {
+        boolean result = ((Plugin) fileAccessor).isThreadSafe() && ((Plugin) fieldsResolver).isThreadSafe();
+        Log.debug("Bridge is " + (result ? "" : "not ") + "thread safe");
+        return result;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/WriteBridge.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/WriteBridge.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/WriteBridge.java
new file mode 100644
index 0000000..34ed316
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/WriteBridge.java
@@ -0,0 +1,96 @@
+package org.apache.hawq.pxf.service;
+
+import org.apache.hawq.pxf.api.*;
+import org.apache.hawq.pxf.api.utilities.InputData;
+import org.apache.hawq.pxf.api.utilities.Plugin;
+import org.apache.hawq.pxf.service.io.Writable;
+import org.apache.hawq.pxf.service.utilities.ProtocolData;
+import org.apache.hawq.pxf.service.utilities.Utilities;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.DataInputStream;
+import java.util.List;
+
+/*
+ * WriteBridge class creates appropriate accessor and resolver.
+ * It reads data from inputStream by the resolver,
+ * and writes it to the Hadoop storage with the accessor.
+ */
+public class WriteBridge implements Bridge {
+    private static final Log LOG = LogFactory.getLog(WriteBridge.class);
+    WriteAccessor fileAccessor = null;
+    WriteResolver fieldsResolver = null;
+    BridgeInputBuilder inputBuilder;
+
+    /*
+     * C'tor - set the implementation of the bridge
+     */
+    public WriteBridge(ProtocolData protocolData) throws Exception {
+    	
+        inputBuilder = new BridgeInputBuilder(protocolData);        
+        /* plugins accept InputData paramaters */
+        fileAccessor = getFileAccessor(protocolData);
+        fieldsResolver = getFieldsResolver(protocolData);
+        
+    }
+
+    /*
+     * Accesses the underlying HDFS file
+     */
+    public boolean beginIteration() throws Exception {
+        return fileAccessor.openForWrite();
+    }
+
+    /*
+     * Read data from stream, convert it using WriteResolver into OneRow object, and
+     * pass to WriteAccessor to write into file.
+     */
+    @Override
+    public boolean setNext(DataInputStream inputStream) throws Exception {
+
+        List<OneField> record = inputBuilder.makeInput(inputStream);
+        if (record == null) {
+            close();
+            return false;
+        }
+
+        OneRow onerow = fieldsResolver.setFields(record);
+        if (onerow == null) {
+            close();
+            return false;
+        }
+        if (!fileAccessor.writeNextObject(onerow)) {
+            close();
+            throw new BadRecordException();
+        }
+        return true;
+    }
+
+    private void close() throws Exception {
+        try {
+            fileAccessor.closeForWrite();
+        } catch (Exception e) {
+            LOG.error("Failed to close bridge resources: " + e.getMessage());
+            throw e;
+        }
+    }
+
+    private static WriteAccessor getFileAccessor(InputData inputData) throws Exception {
+        return (WriteAccessor) Utilities.createAnyInstance(InputData.class, inputData.getAccessor(), inputData);
+    }
+
+    private static WriteResolver getFieldsResolver(InputData inputData) throws Exception {
+        return (WriteResolver) Utilities.createAnyInstance(InputData.class, inputData.getResolver(), inputData);
+    }
+
+    @Override
+    public Writable getNext() {
+        throw new UnsupportedOperationException("getNext is not implemented");
+    }
+
+    @Override
+    public boolean isThreadSafe() {
+        return ((Plugin) fileAccessor).isThreadSafe() && ((Plugin) fieldsResolver).isThreadSafe();
+    }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/BufferWritable.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/BufferWritable.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/BufferWritable.java
new file mode 100644
index 0000000..e74c88b
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/BufferWritable.java
@@ -0,0 +1,57 @@
+package org.apache.hawq.pxf.service.io;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.lang.UnsupportedOperationException;
+
+/**
+ * A serializable object for transporting a byte array through the Bridge
+ * framework
+ */
+public class BufferWritable implements Writable {
+
+    byte[] buf = null;
+
+    /**
+     * Constructs a BufferWritable. Copies the buffer reference and not the
+     * actual bytes. This class is used when we intend to transport a buffer
+     * through the Bridge framework without copying the data each time the
+     * buffer is passed between the Bridge objects.
+     *
+     * @param inBuf buffer
+     */
+    public BufferWritable(byte[] inBuf) {
+        buf = inBuf;
+    }
+
+    /**
+     * Serializes the fields of this object to <code>out</code>.
+     *
+     * @param out <code>DataOutput</code> to serialize this object into.
+     * @throws IOException if the buffer was not set
+     */
+    @Override
+    public void write(DataOutput out) throws IOException {
+        if (buf == null)
+            throw new IOException("BufferWritable was not set");
+        out.write(buf);
+    }
+
+    /**
+     * Deserializes the fields of this object from <code>in</code>.
+     * <p>
+     * For efficiency, implementations should attempt to re-use storage in the
+     * existing object where possible.
+     * </p>
+     *
+     * @param in <code>DataInput</code> to deserialize this object from
+     * @throws UnsupportedOperationException this function is not supported
+     */
+    @Override
+    public void readFields(DataInput in) {
+        throw new UnsupportedOperationException(
+                "BufferWritable.readFields() is not implemented");
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/GPDBWritable.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/GPDBWritable.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/GPDBWritable.java
new file mode 100644
index 0000000..1cce070
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/GPDBWritable.java
@@ -0,0 +1,873 @@
+package org.apache.hawq.pxf.service.io;
+
+import org.apache.hawq.pxf.api.io.DataType;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.*;
+import java.util.Arrays;
+
+import static org.apache.hawq.pxf.api.io.DataType.*;
+
+
+/**
+ * This class represents a GPDB record in the form of
+ * a Java object.
+ */
+public class GPDBWritable implements Writable {
+    /*
+     * GPDBWritable is using the following serialization form:
+	 * Total Length | Version | Error Flag | # of columns | Col type |...| Col type | Null Bit array            |   Col val...
+     * 4 byte		| 2 byte  |	1 byte     |   2 byte     |  1 byte  |...|  1 byte  | ceil(# of columns/8) byte |   Fixed or Var length
+     *
+     * For fixed length type, we know the length.
+     * In the col val, we align pad according to the alignment requirement of the type.
+     * For var length type, the alignment is always 4 byte.
+     * For var length type, col val is <4 byte length><payload val>
+	 */
+
+    private static Log Log = LogFactory.getLog(GPDBWritable.class);
+    private static final int EOF = -1;
+
+    /*
+     * Enum of the Database type
+     */
+    private enum DBType {
+        BIGINT(8, 8),
+        BOOLEAN(1, 1),
+        FLOAT8(8, 8),
+        INTEGER(4, 4),
+        REAL(4, 4),
+        SMALLINT(2, 2),
+        BYTEA(4, -1),
+        TEXT(4, -1);
+
+        private final int typelength; // -1 means var length
+        private final int alignment;
+
+        DBType(int align, int len) {
+            this.typelength = len;
+            this.alignment = align;
+        }
+
+        public int getTypeLength() {
+            return typelength;
+        }
+
+        public boolean isVarLength() {
+            return typelength == -1;
+        }
+
+        // return the alignment requirement of the type
+        public int getAlignment() {
+            return alignment;
+        }
+    }
+
+    /*
+     * Constants
+     */
+    private static final int PREV_VERSION = 1;
+    private static final int VERSION = 2; /* for backward compatibility */
+    private static final String CHARSET = "UTF-8";
+
+    /*
+     * Local variables
+     */
+    protected int[] colType;
+    protected Object[] colValue;
+    protected int alignmentOfEightBytes = 8;
+    protected byte errorFlag = 0;
+    protected int pktlen = EOF;
+
+    public int[] getColType() {
+        return colType;
+    }
+
+    /**
+     * An exception class for column type definition and
+     * set/get value mismatch.
+     */
+    public class TypeMismatchException extends IOException {
+        public TypeMismatchException(String msg) {
+            super(msg);
+        }
+    }
+
+    /**
+     * Empty Constructor
+     */
+    public GPDBWritable() {
+        initializeEightByteAlignment();
+    }
+
+    /**
+     * Constructor to build a db record. colType defines the schema
+     *
+     * @param columnType the table column types
+     */
+    public GPDBWritable(int[] columnType) {
+        initializeEightByteAlignment();
+        colType = columnType;
+        colValue = new Object[columnType.length];
+    }
+
+    /**
+     * Constructor to build a db record from a serialized form.
+     *
+     * @param data a record in the serialized form
+     * @throws IOException if the data is malformatted.
+     */
+    public GPDBWritable(byte[] data) throws IOException {
+        initializeEightByteAlignment();
+        ByteArrayInputStream bis = new ByteArrayInputStream(data);
+        DataInputStream dis = new DataInputStream(bis);
+
+        readFields(dis);
+    }
+
+    /*
+     * Read first 4 bytes, and verify it's a valid packet length.
+     * Upon error returns EOF.
+     */
+    private int readPktLen(DataInput in) throws IOException {
+        pktlen = EOF;
+
+        try {
+            pktlen = in.readInt();
+        } catch (EOFException e) {
+            Log.debug("Reached end of stream (EOFException)");
+            return EOF;
+        }
+        if (pktlen == EOF) {
+            Log.debug("Reached end of stream (returned -1)");
+        }
+
+        return pktlen;
+    }
+
+    @Override
+    public void readFields(DataInput in) throws IOException {
+        /*
+         * extract pkt len.
+		 *
+		 * GPSQL-1107:
+		 * The DataInput might already be empty (EOF), but we can't check it beforehand.
+		 * If that's the case, pktlen is updated to -1, to mark that the object is still empty.
+		 * (can be checked with isEmpty()).
+		 */
+        pktlen = readPktLen(in);
+        if (isEmpty()) {
+            return;
+        }
+
+		/* extract the version and col cnt */
+        int version = in.readShort();
+        int curOffset = 4 + 2;
+        int colCnt;
+
+		/* !!! Check VERSION !!! */
+        if (version != GPDBWritable.VERSION && version != GPDBWritable.PREV_VERSION) {
+            throw new IOException("Current GPDBWritable version(" +
+                    GPDBWritable.VERSION + ") does not match input version(" +
+                    version + ")");
+        }
+
+        if (version == GPDBWritable.VERSION) {
+            errorFlag = in.readByte();
+            curOffset += 1;
+        }
+
+        colCnt = in.readShort();
+        curOffset += 2;
+
+		/* Extract Column Type */
+        colType = new int[colCnt];
+        DBType[] coldbtype = new DBType[colCnt];
+        for (int i = 0; i < colCnt; i++) {
+            int enumType = (in.readByte());
+            curOffset += 1;
+            if (enumType == DBType.BIGINT.ordinal()) {
+                colType[i] = BIGINT.getOID();
+                coldbtype[i] = DBType.BIGINT;
+            } else if (enumType == DBType.BOOLEAN.ordinal()) {
+                colType[i] = BOOLEAN.getOID();
+                coldbtype[i] = DBType.BOOLEAN;
+            } else if (enumType == DBType.FLOAT8.ordinal()) {
+                colType[i] = FLOAT8.getOID();
+                coldbtype[i] = DBType.FLOAT8;
+            } else if (enumType == DBType.INTEGER.ordinal()) {
+                colType[i] = INTEGER.getOID();
+                coldbtype[i] = DBType.INTEGER;
+            } else if (enumType == DBType.REAL.ordinal()) {
+                colType[i] = REAL.getOID();
+                coldbtype[i] = DBType.REAL;
+            } else if (enumType == DBType.SMALLINT.ordinal()) {
+                colType[i] = SMALLINT.getOID();
+                coldbtype[i] = DBType.SMALLINT;
+            } else if (enumType == DBType.BYTEA.ordinal()) {
+                colType[i] = BYTEA.getOID();
+                coldbtype[i] = DBType.BYTEA;
+            } else if (enumType == DBType.TEXT.ordinal()) {
+                colType[i] = TEXT.getOID();
+                coldbtype[i] = DBType.TEXT;
+            } else {
+                throw new IOException("Unknown GPDBWritable.DBType ordinal value");
+            }
+        }
+
+		/* Extract null bit array */
+        byte[] nullbytes = new byte[getNullByteArraySize(colCnt)];
+        in.readFully(nullbytes);
+        curOffset += nullbytes.length;
+        boolean[] colIsNull = byteArrayToBooleanArray(nullbytes, colCnt);
+
+		/* extract column value */
+        colValue = new Object[colCnt];
+        for (int i = 0; i < colCnt; i++) {
+            if (!colIsNull[i]) {
+                /* Skip the alignment padding */
+                int skipbytes = roundUpAlignment(curOffset, coldbtype[i].getAlignment()) - curOffset;
+                for (int j = 0; j < skipbytes; j++) {
+                    in.readByte();
+                }
+                curOffset += skipbytes;
+
+				/* For fixed length type, increment the offset according to type type length here.
+                 * For var length type (BYTEA, TEXT), we'll read 4 byte length header and the
+				 * actual payload.
+				 */
+                int varcollen = -1;
+                if (coldbtype[i].isVarLength()) {
+                    varcollen = in.readInt();
+                    curOffset += 4 + varcollen;
+                } else {
+                    curOffset += coldbtype[i].getTypeLength();
+                }
+
+                switch (DataType.get(colType[i])) {
+                    case BIGINT: {
+                        colValue[i] = in.readLong();
+                        break;
+                    }
+                    case BOOLEAN: {
+                        colValue[i] = in.readBoolean();
+                        break;
+                    }
+                    case FLOAT8: {
+                        colValue[i] = in.readDouble();
+                        break;
+                    }
+                    case INTEGER: {
+                        colValue[i] = in.readInt();
+                        break;
+                    }
+                    case REAL: {
+                        colValue[i] = in.readFloat();
+                        break;
+                    }
+                    case SMALLINT: {
+                        colValue[i] = in.readShort();
+                        break;
+                    }
+
+					/* For BYTEA column, it has a 4 byte var length header. */
+                    case BYTEA: {
+                        colValue[i] = new byte[varcollen];
+                        in.readFully((byte[]) colValue[i]);
+                        break;
+                    }
+                    /* For text formatted column, it has a 4 byte var length header
+                     * and it's always null terminated string.
+					 * So, we can remove the last "\0" when constructing the string.
+					 */
+                    case TEXT: {
+                        byte[] data = new byte[varcollen];
+                        in.readFully(data, 0, varcollen);
+                        colValue[i] = new String(data, 0, varcollen - 1, CHARSET);
+                        break;
+                    }
+
+                    default:
+                        throw new IOException("Unknown GPDBWritable ColType");
+                }
+            }
+        }
+
+		/* Skip the ending alignment padding */
+        int skipbytes = roundUpAlignment(curOffset, 8) - curOffset;
+        for (int j = 0; j < skipbytes; j++) {
+            in.readByte();
+        }
+        curOffset += skipbytes;
+
+        if (errorFlag != 0) {
+            throw new IOException("Received error value " + errorFlag + " from format");
+        }
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+        int numCol = colType.length;
+        boolean[] nullBits = new boolean[numCol];
+        int[] colLength = new int[numCol];
+        byte[] enumType = new byte[numCol];
+        int[] padLength = new int[numCol];
+        byte[] padbytes = new byte[8];
+
+        /**
+         * Compute the total payload and header length
+         * header = total length (4 byte), Version (2 byte), Error (1 byte), #col (2 byte)
+         * col type array = #col * 1 byte
+         * null bit array = ceil(#col/8)
+         */
+        int datlen = 4 + 2 + 1 + 2;
+        datlen += numCol;
+        datlen += getNullByteArraySize(numCol);
+
+        for (int i = 0; i < numCol; i++) {
+            /* Get the enum type */
+            DBType coldbtype;
+            switch (DataType.get(colType[i])) {
+                case BIGINT:
+                    coldbtype = DBType.BIGINT;
+                    break;
+                case BOOLEAN:
+                    coldbtype = DBType.BOOLEAN;
+                    break;
+                case FLOAT8:
+                    coldbtype = DBType.FLOAT8;
+                    break;
+                case INTEGER:
+                    coldbtype = DBType.INTEGER;
+                    break;
+                case REAL:
+                    coldbtype = DBType.REAL;
+                    break;
+                case SMALLINT:
+                    coldbtype = DBType.SMALLINT;
+                    break;
+                case BYTEA:
+                    coldbtype = DBType.BYTEA;
+                    break;
+                default:
+                    coldbtype = DBType.TEXT;
+            }
+            enumType[i] = (byte) (coldbtype.ordinal());
+
+			/* Get the actual value, and set the null bit */
+            if (colValue[i] == null) {
+                nullBits[i] = true;
+                colLength[i] = 0;
+            } else {
+                nullBits[i] = false;
+
+				/*
+                 * For fixed length type, we get the fixed length.
+				 * For var len binary format, the length is in the col value.
+				 * For text format, we must convert encoding first.
+				 */
+                if (!coldbtype.isVarLength()) {
+                    colLength[i] = coldbtype.getTypeLength();
+                } else if (!isTextForm(colType[i])) {
+                    colLength[i] = ((byte[]) colValue[i]).length;
+                } else {
+                    colLength[i] = ((String) colValue[i]).getBytes(CHARSET).length;
+                }
+
+				/* calculate and add the type alignment padding */
+                padLength[i] = roundUpAlignment(datlen, coldbtype.getAlignment()) - datlen;
+                datlen += padLength[i];
+
+				/* for variable length type, we add a 4 byte length header */
+                if (coldbtype.isVarLength()) {
+                    datlen += 4;
+                }
+            }
+            datlen += colLength[i];
+        }
+
+		/*
+		 * Add the final alignment padding for the next record
+		 */
+        int endpadding = roundUpAlignment(datlen, 8) - datlen;
+        datlen += endpadding;
+
+		/* Construct the packet header */
+        out.writeInt(datlen);
+        out.writeShort(VERSION);
+        out.writeByte(errorFlag);
+        out.writeShort(numCol);
+
+		/* Write col type */
+        for (int i = 0; i < numCol; i++) {
+            out.writeByte(enumType[i]);
+        }
+
+		/* Nullness */
+        byte[] nullBytes = boolArrayToByteArray(nullBits);
+        out.write(nullBytes);
+
+		/* Column Value */
+        for (int i = 0; i < numCol; i++) {
+            if (!nullBits[i]) {
+				/* Pad the alignment byte first */
+                if (padLength[i] > 0) {
+                    out.write(padbytes, 0, padLength[i]);
+                }
+
+				/* Now, write the actual column value */
+                switch (DataType.get(colType[i])) {
+                    case BIGINT:
+                        out.writeLong(((Long) colValue[i]));
+                        break;
+                    case BOOLEAN:
+                        out.writeBoolean(((Boolean) colValue[i]));
+                        break;
+                    case FLOAT8:
+                        out.writeDouble(((Double) colValue[i]));
+                        break;
+                    case INTEGER:
+                        out.writeInt(((Integer) colValue[i]));
+                        break;
+                    case REAL:
+                        out.writeFloat(((Float) colValue[i]));
+                        break;
+                    case SMALLINT:
+                        out.writeShort(((Short) colValue[i]));
+                        break;
+
+					/* For BYTEA format, add 4byte length header at the beginning  */
+                    case BYTEA:
+                        out.writeInt(colLength[i]);
+                        out.write((byte[]) colValue[i]);
+                        break;
+
+					/* For text format, add 4byte length header. string is already '\0' terminated */
+                    default: {
+                        out.writeInt(colLength[i]);
+                        byte[] data = ((String) colValue[i]).getBytes(CHARSET);
+                        out.write(data);
+                        break;
+                    }
+                }
+            }
+        }
+
+		/* End padding */
+        out.write(padbytes, 0, endpadding);
+    }
+
+    /**
+     * Private helper to convert boolean array to byte array
+     */
+    private static byte[] boolArrayToByteArray(boolean[] data) {
+        int len = data.length;
+        byte[] byts = new byte[getNullByteArraySize(len)];
+
+        for (int i = 0, j = 0, k = 7; i < data.length; i++) {
+            byts[j] |= (data[i] ? 1 : 0) << k--;
+            if (k < 0) {
+                j++;
+                k = 7;
+            }
+        }
+        return byts;
+    }
+
+    /**
+     * Private helper to determine the size of the null byte array
+     */
+    private static int getNullByteArraySize(int colCnt) {
+        return (colCnt / 8) + (colCnt % 8 != 0 ? 1 : 0);
+    }
+
+    /**
+     * Private helper to convert byte array to boolean array
+     */
+    private static boolean[] byteArrayToBooleanArray(byte[] data, int colCnt) {
+        boolean[] bools = new boolean[colCnt];
+        for (int i = 0, j = 0, k = 7; i < bools.length; i++) {
+            bools[i] = ((data[j] >> k--) & 0x01) == 1;
+            if (k < 0) {
+                j++;
+                k = 7;
+            }
+        }
+        return bools;
+    }
+
+    /**
+     * Private helper to round up alignment for the given length
+     */
+    private int roundUpAlignment(int len, int align) {
+        int commonAlignment = align;
+        if (commonAlignment == 8) {
+            commonAlignment = alignmentOfEightBytes;
+        }
+        return (((len) + ((commonAlignment) - 1)) & ~((commonAlignment) - 1));
+    }
+
+    /**
+     * Getter/Setter methods to get/set the column value
+     */
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setLong(int colIdx, Long val)
+            throws TypeMismatchException {
+        checkType(BIGINT, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setBoolean(int colIdx, Boolean val)
+            throws TypeMismatchException {
+        checkType(BOOLEAN, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setBytes(int colIdx, byte[] val)
+            throws TypeMismatchException {
+        checkType(BYTEA, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setString(int colIdx, String val)
+            throws TypeMismatchException {
+        checkType(TEXT, colIdx, true);
+        if (val != null) {
+            colValue[colIdx] = val + "\0";
+        } else {
+            colValue[colIdx] = val;
+        }
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setFloat(int colIdx, Float val)
+            throws TypeMismatchException {
+        checkType(REAL, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setDouble(int colIdx, Double val)
+            throws TypeMismatchException {
+        checkType(FLOAT8, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setInt(int colIdx, Integer val)
+            throws TypeMismatchException {
+        checkType(INTEGER, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Sets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @param val    the value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public void setShort(int colIdx, Short val)
+            throws TypeMismatchException {
+        checkType(SMALLINT, colIdx, true);
+        colValue[colIdx] = val;
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Long getLong(int colIdx)
+            throws TypeMismatchException {
+        checkType(BIGINT, colIdx, false);
+        return (Long) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Boolean getBoolean(int colIdx)
+            throws TypeMismatchException {
+        checkType(BOOLEAN, colIdx, false);
+        return (Boolean) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public byte[] getBytes(int colIdx)
+            throws TypeMismatchException {
+        checkType(BYTEA, colIdx, false);
+        return (byte[]) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public String getString(int colIdx)
+            throws TypeMismatchException {
+        checkType(TEXT, colIdx, false);
+        return (String) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Float getFloat(int colIdx)
+            throws TypeMismatchException {
+        checkType(REAL, colIdx, false);
+        return (Float) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Double getDouble(int colIdx)
+            throws TypeMismatchException {
+        checkType(FLOAT8, colIdx, false);
+        return (Double) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Integer getInt(int colIdx)
+            throws TypeMismatchException {
+        checkType(INTEGER, colIdx, false);
+        return (Integer) colValue[colIdx];
+    }
+
+    /**
+     * Gets the column value of the record.
+     *
+     * @param colIdx the column index
+     * @return column value
+     * @throws TypeMismatchException the column type does not match
+     */
+    public Short getShort(int colIdx)
+            throws TypeMismatchException {
+        checkType(SMALLINT, colIdx, false);
+        return (Short) colValue[colIdx];
+    }
+
+    /**
+     * Sets the error field.
+     *
+     * @param errorVal the error value
+     */
+    public void setError(boolean errorVal) {
+        errorFlag = errorVal ? (byte) 1 : (byte) 0;
+    }
+
+    /**
+     * Returns a string representation of the object.
+     */
+    @Override
+    public String toString() {
+        if (colType == null) {
+            return null;
+        }
+        StringBuilder result = new StringBuilder();
+        for (int i = 0; i < colType.length; i++) {
+            result.append("Column ").append(i).append(":");
+            if (colValue[i] != null) {
+                result.append(colType[i] == BYTEA.getOID()
+                        ? byteArrayInString((byte[]) colValue[i])
+                        : colValue[i]);
+            }
+            result.append("\n");
+        }
+        return result.toString();
+    }
+
+    /**
+     * Helper printing function
+     */
+    private static String byteArrayInString(byte[] data) {
+        StringBuilder result = new StringBuilder();
+        for (Byte b : data) {
+            result.append(b.intValue()).append(" ");
+        }
+        return result.toString();
+    }
+
+    /**
+     * Private Helper to check the type mismatch
+     * If the expected type is stored as string, then it must be set
+     * via setString.
+     * Otherwise, the type must match.
+     */
+    private void checkType(DataType inTyp, int idx, boolean isSet)
+            throws TypeMismatchException {
+        if (idx < 0 || idx >= colType.length) {
+            throw new TypeMismatchException("Column index is out of range");
+        }
+
+        int exTyp = colType[idx];
+
+        if (isTextForm(exTyp)) {
+            if (inTyp != TEXT) {
+                throw new TypeMismatchException(formErrorMsg(inTyp.getOID(), TEXT.getOID(), isSet));
+            }
+        } else if (inTyp != DataType.get(exTyp)) {
+            throw new TypeMismatchException(formErrorMsg(inTyp.getOID(), exTyp, isSet));
+        }
+    }
+
+    private String formErrorMsg(int inTyp, int colTyp, boolean isSet) {
+        return isSet
+                ? "Cannot set " + getTypeName(inTyp) + " to a " + getTypeName(colTyp) + " column"
+                : "Cannot get " + getTypeName(inTyp) + " from a " + getTypeName(colTyp) + " column";
+    }
+
+    /**
+     * Private Helper routine to tell whether a type is Text form or not
+     *
+     * @param type the type OID that we want to check
+     */
+    private boolean isTextForm(int type) {
+        return !Arrays.asList(BIGINT, BOOLEAN, BYTEA, FLOAT8, INTEGER, REAL, SMALLINT).contains(DataType.get(type));
+    }
+
+    /**
+     * Helper to get the type name.
+     * If a given oid is not in the commonly used list, we
+     * would expect a TEXT for it (for the error message).
+     *
+     * @param oid type OID
+     * @return type name
+     */
+    public static String getTypeName(int oid) {
+        switch (DataType.get(oid)) {
+            case BOOLEAN:
+                return "BOOLEAN";
+            case BYTEA:
+                return "BYTEA";
+            case CHAR:
+                return "CHAR";
+            case BIGINT:
+                return "BIGINT";
+            case SMALLINT:
+                return "SMALLINT";
+            case INTEGER:
+                return "INTEGER";
+            case TEXT:
+                return "TEXT";
+            case REAL:
+                return "REAL";
+            case FLOAT8:
+                return "FLOAT8";
+            case BPCHAR:
+                return "BPCHAR";
+            case VARCHAR:
+                return "VARCHAR";
+            case DATE:
+                return "DATE";
+            case TIME:
+                return "TIME";
+            case TIMESTAMP:
+                return "TIMESTAMP";
+            case NUMERIC:
+                return "NUMERIC";
+            default:
+                return "TEXT";
+        }
+    }
+
+    /*
+     * Get alignment from command line to match to the alignment
+     * the C code uses (see gphdfs/src/protocol_formatter/common.c).
+     */
+    private void initializeEightByteAlignment() {
+        String alignment = System.getProperty("greenplum.alignment");
+        if (alignment == null) {
+            return;
+        }
+        alignmentOfEightBytes = Integer.parseInt(alignment);
+    }
+
+    /**
+     * Returns if the writable object is empty,
+     * based on the pkt len as read from stream.
+     * -1 means nothing was read (eof).
+     *
+     * @return whether the writable object is empty
+     */
+    public boolean isEmpty() {
+        return pktlen == EOF;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Text.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Text.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Text.java
new file mode 100644
index 0000000..cdea1de
--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Text.java
@@ -0,0 +1,379 @@
+package org.apache.hawq.pxf.service.io;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import java.io.DataInput;
+import java.io.DataInputStream;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.*;
+import java.util.Arrays;
+
+/**
+ * This class stores text using standard UTF8 encoding. It provides methods to
+ * serialize, deserialize. The type of length is integer and is serialized using
+ * zero-compressed format.
+ */
+public class Text implements Writable {
+
+    // for write
+    private byte[] buf;
+    private static final Log LOG = LogFactory.getLog(Text.class);
+    int curLoc;
+    private static final char LINE_DELIMITER = '\n';
+    private static final int BUF_SIZE = 1024;
+    private static final int EOF = -1;
+
+    private static final byte[] EMPTY_BYTES = new byte[0];
+    private static ThreadLocal<CharsetEncoder> ENCODER_FACTORY = new ThreadLocal<CharsetEncoder>() {
+        @Override
+        protected CharsetEncoder initialValue() {
+            return Charset.forName("UTF-8").newEncoder().onMalformedInput(
+                    CodingErrorAction.REPORT).onUnmappableCharacter(
+                    CodingErrorAction.REPORT);
+        }
+    };
+    private static ThreadLocal<CharsetDecoder> DECODER_FACTORY = new ThreadLocal<CharsetDecoder>() {
+        @Override
+        protected CharsetDecoder initialValue() {
+            return Charset.forName("UTF-8").newDecoder().onMalformedInput(
+                    CodingErrorAction.REPORT).onUnmappableCharacter(
+                    CodingErrorAction.REPORT);
+        }
+    };
+    private byte[] bytes;
+    private int length;
+
+    public Text() {
+        bytes = EMPTY_BYTES;
+        buf = new byte[BUF_SIZE];
+    }
+
+    /**
+     * Construct from a string.
+     *
+     * @param string input string
+     */
+    public Text(String string) {
+        set(string);
+    }
+
+    /**
+     * Construct from another text.
+     *
+     * @param utf8 text to copy
+     */
+    public Text(Text utf8) {
+        set(utf8);
+    }
+
+    /**
+     * Construct from a byte array.
+     *
+     * @param utf8 input byte array
+     */
+    public Text(byte[] utf8) {
+        set(utf8);
+    }
+
+    public static boolean isNegativeVInt(byte value) {
+        return value < -120 || (value >= -112 && value < 0);
+    }
+
+    public static long readVLong(DataInput stream) throws IOException {
+        byte firstByte = stream.readByte();
+        int len = decodeVIntSize(firstByte);
+        if (len == 1) {
+            return firstByte;
+        }
+        long i = 0;
+        for (int idx = 0; idx < len - 1; idx++) {
+            byte b = stream.readByte();
+            i = i << 8;
+            i = i | (b & 0xFF);
+        }
+        return (isNegativeVInt(firstByte) ? (i ^ -1L) : i);
+    }
+
+    public static int decodeVIntSize(byte value) {
+        if (value >= -112) {
+            return 1;
+        } else if (value < -120) {
+            return -119 - value;
+        }
+        return -111 - value;
+    }
+
+    public static String decode(byte[] utf8, int start, int length)
+            throws CharacterCodingException {
+        return decode(ByteBuffer.wrap(utf8, start, length), true);
+    }
+
+    /**
+     * Converts the provided byte array to a String using the UTF-8 encoding. If
+     * <code>replace</code> is true, then malformed input is replaced with the
+     * substitution character, which is U+FFFD. Otherwise the method throws a
+     * MalformedInputException.
+     *
+     * @param utf8 UTF-8 encoded byte array
+     * @param start start point
+     * @param length length of array
+     * @param replace whether to replace malformed input with substitution
+     *            character
+     * @return decoded string
+     * @throws MalformedInputException if a malformed input is used
+     * @throws CharacterCodingException if the conversion failed
+     */
+    public static String decode(byte[] utf8, int start, int length,
+                                boolean replace)
+            throws CharacterCodingException {
+        return decode(ByteBuffer.wrap(utf8, start, length), replace);
+    }
+
+    private static String decode(ByteBuffer utf8, boolean replace)
+            throws CharacterCodingException {
+        CharsetDecoder decoder = DECODER_FACTORY.get();
+        if (replace) {
+            decoder.onMalformedInput(java.nio.charset.CodingErrorAction.REPLACE);
+            decoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
+        }
+        String str = decoder.decode(utf8).toString();
+        // set decoder back to its default value: REPORT
+        if (replace) {
+            decoder.onMalformedInput(CodingErrorAction.REPORT);
+            decoder.onUnmappableCharacter(CodingErrorAction.REPORT);
+        }
+        return str;
+    }
+
+    /**
+     * Converts the provided String to bytes using the UTF-8 encoding. If the
+     * input is malformed, invalid chars are replaced by a default value.
+     *
+     * @param string string to encode
+     * @return ByteBuffer: bytes stores at ByteBuffer.array() and length is
+     *         ByteBuffer.limit()
+     * @throws CharacterCodingException if conversion failed
+     */
+    public static ByteBuffer encode(String string)
+            throws CharacterCodingException {
+        return encode(string, true);
+    }
+
+    /**
+     * Converts the provided String to bytes using the UTF-8 encoding. If
+     * <code>replace</code> is true, then malformed input is replaced with the
+     * substitution character, which is U+FFFD. Otherwise the method throws a
+     * MalformedInputException.
+     *
+     * @param string string to encode
+     * @param replace whether to replace malformed input with substitution character
+     * @return ByteBuffer: bytes stores at ByteBuffer.array() and length is
+     *         ByteBuffer.limit()
+     * @throws MalformedInputException if a malformed input is used
+     * @throws CharacterCodingException if the conversion failed
+     */
+    public static ByteBuffer encode(String string, boolean replace)
+            throws CharacterCodingException {
+        CharsetEncoder encoder = ENCODER_FACTORY.get();
+        if (replace) {
+            encoder.onMalformedInput(CodingErrorAction.REPLACE);
+            encoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
+        }
+        ByteBuffer bytes = encoder.encode(CharBuffer.wrap(string.toCharArray()));
+        if (replace) {
+            encoder.onMalformedInput(CodingErrorAction.REPORT);
+            encoder.onUnmappableCharacter(CodingErrorAction.REPORT);
+        }
+        return bytes;
+    }
+
+    /**
+     * Returns the raw bytes; however, only data up to {@link #getLength()} is
+     * valid.
+     *
+     * @return raw bytes of byte array
+     */
+    public byte[] getBytes() {
+        return bytes;
+    }
+
+    /**
+     * Returns the number of bytes in the byte array
+     *
+     * @return number of bytes in byte array
+     */
+    public int getLength() {
+        return length;
+    }
+
+    /**
+     * Sets to contain the contents of a string.
+     *
+     * @param string input string
+     */
+    public void set(String string) {
+        try {
+            ByteBuffer bb = encode(string, true);
+            bytes = bb.array();
+            length = bb.limit();
+        } catch (CharacterCodingException e) {
+            throw new RuntimeException("Should not have happened "
+                    + e.toString());
+        }
+    }
+
+    /**
+     * Sets to a UTF-8 byte array.
+     *
+     * @param utf8 input UTF-8 byte array
+     */
+    public void set(byte[] utf8) {
+        set(utf8, 0, utf8.length);
+    }
+
+    /**
+     * Copies a text.
+     *
+     * @param other text object to copy.
+     */
+    public void set(Text other) {
+        set(other.getBytes(), 0, other.getLength());
+    }
+
+    /**
+     * Sets the Text to range of bytes.
+     *
+     * @param utf8 the data to copy from
+     * @param start the first position of the new string
+     * @param len the number of bytes of the new string
+     */
+    public void set(byte[] utf8, int start, int len) {
+        setCapacity(len, false);
+        System.arraycopy(utf8, start, bytes, 0, len);
+        this.length = len;
+    }
+
+    /**
+     * Appends a range of bytes to the end of the given text.
+     *
+     * @param utf8 the data to copy from
+     * @param start the first position to append from utf8
+     * @param len the number of bytes to append
+     */
+    public void append(byte[] utf8, int start, int len) {
+        setCapacity(length + len, true);
+        System.arraycopy(utf8, start, bytes, length, len);
+        length += len;
+    }
+
+    /**
+     * Clears the string to empty.
+     */
+    public void clear() {
+        length = 0;
+    }
+
+    /*
+     * Sets the capacity of this Text object to <em>at least</em>
+     * <code>len</code> bytes. If the current buffer is longer, then the
+     * capacity and existing content of the buffer are unchanged. If
+     * <code>len</code> is larger than the current capacity, the Text object's
+     * capacity is increased to match.
+     *
+     * @param len the number of bytes we need
+     *
+     * @param keepData should the old data be kept
+     */
+    private void setCapacity(int len, boolean keepData) {
+        if (bytes == null || bytes.length < len) {
+            byte[] newBytes = new byte[len];
+            if (bytes != null && keepData) {
+                System.arraycopy(bytes, 0, newBytes, 0, length);
+            }
+            bytes = newBytes;
+        }
+    }
+
+    /**
+     * Convert text back to string
+     *
+     * @see java.lang.Object#toString()
+     */
+    @Override
+    public String toString() {
+        try {
+            return decode(bytes, 0, length);
+        } catch (CharacterCodingException e) {
+            throw new RuntimeException("Should not have happened "
+                    + e.toString());
+        }
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+        byte[] bytes = getBytes();
+        out.write(bytes, 0, getLength());
+    }
+
+    /**
+     * deserialize
+     */
+    @Override
+    public void readFields(DataInput inputStream) throws IOException {
+
+        byte c;
+        curLoc = 0;
+        clear();
+        while ((c = (byte) ((DataInputStream) inputStream).read()) != EOF) {
+            buf[curLoc] = c;
+            curLoc++;
+
+            if (c == LINE_DELIMITER) {
+                LOG.trace("read one line, size " + curLoc);
+                break;
+            }
+
+            if (isBufferFull()) {
+                flushBuffer();
+            }
+        }
+
+        if (!isBufferEmpty()) {
+            // the buffer doesn't end with a line break.
+            if (c == EOF) {
+                LOG.warn("Stream ended without line break");
+            }
+            flushBuffer();
+        }
+    }
+
+    private boolean isBufferEmpty() {
+        return (curLoc == 0);
+    }
+
+    private boolean isBufferFull() {
+        return (curLoc == BUF_SIZE);
+    }
+
+    private void flushBuffer() {
+        append(buf, 0, curLoc);
+        curLoc = 0;
+    }
+
+    /**
+     * Returns true iff <code>o</code> is a Text with the same contents.
+     */
+    @Override
+    public boolean equals(Object o) {
+        return (o instanceof Text && Arrays.equals(bytes, ((Text) o).bytes));
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(bytes);
+    }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/1c7ab9eb/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Writable.java
----------------------------------------------------------------------
diff --git a/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Writable.java b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Writable.java
new file mode 100644
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--- /dev/null
+++ b/pxf/pxf-service/src/main/java/org/apache/hawq/pxf/service/io/Writable.java
@@ -0,0 +1,30 @@
+package org.apache.hawq.pxf.service.io;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+/**
+ * A serializable object which implements a simple, efficient, serialization
+ * protocol, based on {@link DataInput} and {@link DataOutput}.
+ */
+public interface Writable {
+
+    /**
+     * Serialize the fields of this object to <code>out</code>.
+     *
+     * @param out <code>DataOutput</code> to serialize this object into.
+     * @throws IOException if I/O error occurs
+     */
+    void write(DataOutput out) throws IOException;
+
+    /**
+     * Deserialize the fields of this object from <code>in</code>.
+     * <p>For efficiency, implementations should attempt to re-use storage in the
+     * existing object where possible.</p>
+     *
+     * @param in <code>DataInput</code> to deserialize this object from.
+     * @throws IOException if I/O error occurs
+     */
+    void readFields(DataInput in) throws IOException;
+}