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 Tue, 02 Feb 2016 00:19:25 GMT
Github user hornn commented on a diff in the pull request:

    https://github.com/apache/incubator-hawq/pull/302#discussion_r51503825
  
    --- Diff: pxf/pxf-json/src/main/java/org/apache/hawq/pxf/plugins/json/JsonResolver.java
---
    @@ -0,0 +1,281 @@
    +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 java.util.regex.Matcher;
    +import java.util.regex.Pattern;
    +
    +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 static Pattern ARRAY_PROJECTION_PATTERN = Pattern.compile("(.*)\\[([0-9]+)\\]");
    +
    +	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 = JsonUtil.decodeLineToJsonNode(row.getData().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
    +	 */
    --- End diff --
    
    /Users/nhorn/dev/hawq/apache-hawq/pxf/pxf-json/src/main/java/org/apache/hawq/pxf/plugins/json/JsonResolver.java:122:
warning - @return tag has no arguments.
    1 warning


---
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