hawq-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From hornn <...@git.apache.org>
Subject [GitHub] incubator-hawq pull request: HAWQ-178: Add JSON plugin support in ...
Date Fri, 29 Jan 2016 20:59:53 GMT
Github user hornn commented on a diff in the pull request:

    https://github.com/apache/incubator-hawq/pull/302#discussion_r51314932
  
    --- Diff: pxf/pxf-json/src/main/java/org/apache/hawq/pxf/plugins/json/JsonResolver.java
---
    @@ -0,0 +1,259 @@
    +package org.apache.hawq.pxf.plugins.json;
    +
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + * 
    + *   http://www.apache.org/licenses/LICENSE-2.0
    + * 
    + * Unless required by applicable law or agreed to in writing,
    + * software distributed under the License is distributed on an
    + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    + * KIND, either express or implied.  See the License for the
    + * specific language governing permissions and limitations
    + * under the License.
    + */
    +
    +import java.io.IOException;
    +import java.security.InvalidParameterException;
    +import java.util.ArrayList;
    +import java.util.Iterator;
    +import java.util.List;
    +
    +import org.apache.hawq.pxf.api.OneField;
    +import org.apache.hawq.pxf.api.OneRow;
    +import org.apache.hawq.pxf.api.ReadResolver;
    +import org.apache.hawq.pxf.api.io.DataType;
    +import org.apache.hawq.pxf.api.utilities.ColumnDescriptor;
    +import org.apache.hawq.pxf.api.utilities.InputData;
    +import org.apache.hawq.pxf.api.utilities.Plugin;
    +import org.codehaus.jackson.JsonNode;
    +
    +/**
    + * This JSON resolver for PXF will decode a given object from the {@link JsonAccessor}
into a row for HAWQ. It will
    + * decode this data into a JsonNode and walk the tree for each column. It supports normal
value mapping via projections
    + * and JSON array indexing.
    + */
    +public class JsonResolver extends Plugin implements ReadResolver {
    +
    +	private ArrayList<OneField> list = new ArrayList<OneField>();
    +
    +	public JsonResolver(InputData inputData) throws Exception {
    +		super(inputData);
    +	}
    +
    +	@Override
    +	public List<OneField> getFields(OneRow row) throws Exception {
    +		list.clear();
    +
    +		// key is a Text object
    +		JsonNode root = JsonInputFormat.decodeLineToJsonNode(row.getKey().toString());
    +
    +		// if we weren't given a null object
    +		if (root != null) {
    +			// Iterate through the column definition and fetch our JSON data
    +			for (int i = 0; i < inputData.getColumns(); ++i) {
    +
    +				// Get the current column description
    +				ColumnDescriptor cd = inputData.getColumn(i);
    +				DataType columnType = DataType.get(cd.columnTypeCode());
    +
    +				// Get the JSON projections from the column name
    +				// For example, "user.name" turns into ["user","name"]
    +				String[] projs = cd.columnName().split("\\.");
    +
    +				// Move down the JSON path to the final name
    +				JsonNode node = getPriorJsonNode(root, projs);
    +
    +				// If this column is an array index, ex. "tweet.hashtags[0]"
    +				if (isArrayIndex(projs)) {
    +
    +					// Get the node name and index
    +					String nodeName = getArrayName(projs);
    +					int arrayIndex = getArrayIndex(projs);
    +
    +					// Move to the array node
    +					node = node.get(nodeName);
    +
    +					// If this node is null or missing, add a null value here
    +					if (node == null || node.isMissingNode()) {
    +						addNullField(columnType);
    +					} else if (node.isArray()) {
    +						// If the JSON node is an array, then add it to our list
    +						addFieldFromJsonArray(columnType, node, arrayIndex);
    +					} else {
    +						throw new InvalidParameterException(nodeName + " is not an array node");
    +					}
    +				} else {
    +					// This column is not an array type
    +					// Move to the final node
    +					node = node.get(projs[projs.length - 1]);
    +
    +					// If this node is null or missing, add a null value here
    +					if (node == null || node.isMissingNode()) {
    +						addNullField(columnType);
    +					} else {
    +						// Else, add the value to the record
    +						addFieldFromJsonNode(columnType, node);
    +					}
    +				}
    +			}
    +		}
    +
    +		return list;
    +	}
    +
    +	/**
    +	 * Iterates down the root node to the prior JSON node. This node is used
    +	 * 
    +	 * @param root
    +	 * @param projs
    +	 * @return
    +	 */
    +	private JsonNode getPriorJsonNode(JsonNode root, String[] projs) {
    +
    +		// Iterate through all the tokens to the desired JSON node
    +		JsonNode node = root;
    +		for (int j = 0; j < projs.length - 1; ++j) {
    +			node = node.path(projs[j]);
    +		}
    +
    +		return node;
    +	}
    +
    +	/**
    +	 * Gets a boolean value indicating if this column is an array index column
    +	 * 
    +	 * @param projs
    +	 *            The array of JSON projections
    +	 * @throws ArrayIndexOutOfBoundsException
    +	 */
    +	private boolean isArrayIndex(String[] projs) {
    +		return projs[projs.length - 1].contains("[") && projs[projs.length - 1].contains("]");
    +	}
    +
    +	/**
    +	 * Gets the node name from the given String array of JSON projections, parsed from the
ColumnDescriptor's
    +	 * 
    +	 * @param projs
    +	 *            The array of JSON projections
    +	 * @return The name
    +	 * @throws ArrayIndexOutOfBoundsException
    +	 */
    +	private String getArrayName(String[] projs) {
    +		return projs[projs.length - 1].replaceAll("\\[[0-9]+\\]", "");
    +	}
    +
    +	/**
    +	 * Gets the array index from the given String array of JSON projections, parsed from
the ColumnDescriptor's name
    +	 * 
    +	 * @param projs
    +	 *            The array of JSON projections
    +	 * @return The index
    +	 * @throws ArrayIndexOutOfBoundsException
    +	 */
    +	private int getArrayIndex(String[] projs) {
    +		return Integer.parseInt(projs[projs.length - 1].substring(projs[projs.length - 1].indexOf('[')
+ 1,
    +				projs[projs.length - 1].length() - 1));
    +	}
    +
    +	/**
    +	 * Iterates through the given JSON node to the proper index and adds the field of corresponding
type
    +	 * 
    +	 * @param type
    +	 *            The {@link DataType} type
    +	 * @param node
    +	 *            The JSON array node
    +	 * @param index
    +	 *            The array index to iterate to
    +	 * @throws IOException
    +	 */
    +	private void addFieldFromJsonArray(DataType type, JsonNode node, int index) throws IOException
{
    +
    +		int count = 0;
    +		boolean added = false;
    +		for (Iterator<JsonNode> arrayNodes = node.getElements(); arrayNodes.hasNext();)
{
    +			JsonNode arrayNode = arrayNodes.next();
    +
    +			if (count == index) {
    +				added = true;
    +				addFieldFromJsonNode(type, arrayNode);
    +				break;
    +			}
    +
    +			++count;
    +		}
    +
    +		// if we reached the end of the array without adding a
    +		// field, add null
    +		if (!added) {
    +			addNullField(type);
    +		}
    +	}
    +
    +	/**
    +	 * Adds a field from a given JSON node value based on the {@link DataType} type.
    +	 * 
    +	 * @param type
    +	 *            The DataType type
    +	 * @param val
    +	 *            The JSON node to extract the value.
    +	 * @throws IOException
    +	 */
    +	private void addFieldFromJsonNode(DataType type, JsonNode val) throws IOException {
    +		OneField oneField = new OneField();
    +		oneField.type = type.getOID();
    +
    +		if (val.isNull()) {
    +			oneField.val = null;
    +		} else {
    +			switch (type) {
    +			case BIGINT:
    +				oneField.val = val.asLong();
    +				break;
    +			case BOOLEAN:
    +				oneField.val = val.asBoolean();
    +				break;
    +			case BPCHAR:
    --- End diff --
    
    BPCHAR should be treated like VARCHAR and TEXT - it's more than one character.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message