/**
* 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.
*/
package org.apache.hadoop.hive.ql.udf.xml;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters.Converter;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.Text;
import org.w3c.dom.NodeList;
@Description(
name = "xpath",
value = "_FUNC_(xml, xpath) - Returns a string array of values within xml nodes that match the xpath expression",
extended = "Example:\n"
+ " > SELECT _FUNC_('<a><b>b1</b><b>b2</b><b>b3</b><c>c1</c><c>c2</c></a>', 'a/text()') FROM src LIMIT 1\n"
+ " []\n"
+ " > SELECT _FUNC_('<a><b>b1</b><b>b2</b><b>b3</b><c>c1</c><c>c2</c></a>', 'a/b/text()') FROM src LIMIT 1\n"
+ " [\"b1\",\"b2\",\"b3\"]\n"
+ " > SELECT _FUNC_('<a><b>b1</b><b>b2</b><b>b3</b><c>c1</c><c>c2</c></a>', 'a/c/text()') FROM src LIMIT 1\n"
+ " [\"c1\",\"c2\"]"
)
public class GenericUDFXPath extends GenericUDF {
private static final List<Text> emptyResult = Collections.<Text>emptyList();
private transient final UDFXPathUtil xpath = new UDFXPathUtil();
private final List<Text> result = new ArrayList<Text>(10);
private transient Converter converterArg0;
private transient Converter converterArg1;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments)
throws UDFArgumentException {
if (arguments.length != 2) {
throw new UDFArgumentException("Invalid number of arguments.");
}
converterArg0 = ObjectInspectorConverters.getConverter(arguments[0],
PrimitiveObjectInspectorFactory.writableStringObjectInspector);
converterArg1 = ObjectInspectorConverters.getConverter(arguments[1],
PrimitiveObjectInspectorFactory.writableStringObjectInspector);
return ObjectInspectorFactory
.getStandardListObjectInspector(PrimitiveObjectInspectorFactory.writableStringObjectInspector);
}
private List<Text> eval(String xml, String path) {
NodeList nodeList = xpath.evalNodeList(xml, path);
if (nodeList == null) {
return emptyResult;
}
result.clear();
for (int i = 0; i < nodeList.getLength(); i++) {
String value = nodeList.item(i).getNodeValue();
if (value != null) {
result.add(new Text(value));
}
}
return result;
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
assert (arguments.length == 2);
String xml = converterArg0.convert(arguments[0].get()).toString();
String path = converterArg1.convert(arguments[1].get()).toString();
return eval(xml, path);
}
@Override
public String getDisplayString(String[] children) {
StringBuilder builder = new StringBuilder();
builder.append("array (");
if (children.length > 0) {
builder.append("'");
builder.append(StringUtils.join(children, "','"));
builder.append("'");
}
builder.append(")");
return builder.toString();
}
}