/**
* 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.generic;
import java.util.LinkedHashMap;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.serde2.objectinspector.ListObjectInspector;
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.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.VoidObjectInspector;
/**
* GenericUDFMap.
*
*/
@Description(name = "map", value = "_FUNC_(key0, value0, key1, value1...) - "
+ "Creates a map with the given key/value pairs ")
public class GenericUDFMap extends GenericUDF {
private transient Converter[] converters;
// Must be deterministic order map for consistent q-test output across Java versions - see HIVE-9161
LinkedHashMap<Object, Object> ret = new LinkedHashMap<Object, Object>();
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
if (arguments.length % 2 != 0) {
throw new UDFArgumentLengthException(
"Arguments must be in key/value pairs");
}
GenericUDFUtils.ReturnObjectInspectorResolver keyOIResolver =
new GenericUDFUtils.ReturnObjectInspectorResolver(true);
GenericUDFUtils.ReturnObjectInspectorResolver valueOIResolver =
new GenericUDFUtils.ReturnObjectInspectorResolver(true);
for (int i = 0; i < arguments.length; i++) {
if (i % 2 == 0) {
// Keys
if (!(arguments[i] instanceof PrimitiveObjectInspector)) {
throw new UDFArgumentTypeException(1,
"Primitive Type is expected but " + arguments[i].getTypeName()
+ "\" is found");
}
if (!keyOIResolver.update(arguments[i])) {
throw new UDFArgumentTypeException(i, "Key type \""
+ arguments[i].getTypeName()
+ "\" is different from preceding key types. "
+ "Previous key type was \"" + arguments[i - 2].getTypeName()
+ "\"");
}
} else {
// Values
if (!valueOIResolver.update(arguments[i]) && !compatibleTypes(arguments[i], arguments[i-2])) {
throw new UDFArgumentTypeException(i, "Value type \""
+ arguments[i].getTypeName()
+ "\" is different from preceding value types. "
+ "Previous value type was \"" + arguments[i - 2].getTypeName()
+ "\"");
}
}
}
ObjectInspector keyOI =
keyOIResolver.get(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
ObjectInspector valueOI =
valueOIResolver.get(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
converters = new Converter[arguments.length];
for (int i = 0; i < arguments.length; i++) {
converters[i] = ObjectInspectorConverters.getConverter(arguments[i],
i % 2 == 0 ? keyOI : valueOI);
}
return ObjectInspectorFactory.getStandardMapObjectInspector(keyOI, valueOI);
}
private boolean compatibleTypes(ObjectInspector current, ObjectInspector prev) {
if (current instanceof VoidObjectInspector || prev instanceof VoidObjectInspector) {
// we allow null values for map.
return true;
}
if (current instanceof ListObjectInspector && prev instanceof ListObjectInspector && (
((ListObjectInspector)current).getListElementObjectInspector() instanceof VoidObjectInspector ||
((ListObjectInspector)prev).getListElementObjectInspector() instanceof VoidObjectInspector)) {
// array<null> is compatible with any other array<type>
return true;
}
return false;
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
ret.clear();
for (int i = 0; i < arguments.length; i += 2) {
ret.put(converters[i].convert(arguments[i].get()), converters[i + 1]
.convert(arguments[i + 1].get()));
}
return ret;
}
@Override
public String getDisplayString(String[] children) {
StringBuilder sb = new StringBuilder();
sb.append("map(");
assert (children.length % 2 == 0);
for (int i = 0; i < children.length; i += 2) {
sb.append(children[i]);
sb.append(":");
sb.append(children[i + 1]);
if (i + 2 != children.length) {
sb.append(",");
}
}
sb.append(")");
return sb.toString();
}
}