/**
* 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.io.Serializable;
import java.lang.reflect.Method;
import java.util.ArrayList;
import org.apache.hadoop.hive.common.JavaUtils;
import org.apache.hadoop.hive.common.type.HiveDecimal;
import org.apache.hadoop.hive.ql.exec.FunctionRegistry;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDFUtils.ConversionHelper;
import org.apache.hadoop.hive.serde2.io.HiveDecimalWritable;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory.ObjectInspectorOptions;
import org.apache.hadoop.hive.serde2.typeinfo.HiveDecimalUtils;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
/**
* GenericUDFBridge encapsulates UDF to provide the same interface as
* GenericUDF.
*
* Note that GenericUDFBridge implements Serializable because the name of the
* UDF class needs to be serialized with the plan.
*
*/
public class GenericUDFBridge extends GenericUDF implements Serializable {
private static final long serialVersionUID = 4994861742809511113L;
/**
* The name of the UDF.
*/
private String udfName;
/**
* Whether the UDF is an operator or not. This controls how the display string
* is generated.
*/
private boolean isOperator;
/**
* The underlying UDF class Name.
*/
private String udfClassName;
/**
* The underlying method of the UDF class.
*/
private transient Method udfMethod;
/**
* Helper to convert the parameters before passing to udfMethod.
*/
private transient ConversionHelper conversionHelper;
/**
* The actual udf object.
*/
private transient UDF udf;
/**
* The non-deferred real arguments for method invocation.
*/
private transient Object[] realArguments;
/**
* Create a new GenericUDFBridge object.
*
* @param udfName
* The name of the corresponding udf.
* @param isOperator true for operators
* @param udfClassName java class name of UDF
*/
public GenericUDFBridge(String udfName, boolean isOperator,
String udfClassName) {
this.udfName = udfName;
this.isOperator = isOperator;
this.udfClassName = udfClassName;
}
// For Java serialization only
public GenericUDFBridge() {
}
public void setUdfName(String udfName) {
this.udfName = udfName;
}
@Override
public String getUdfName() {
return udfName;
}
public String getUdfClassName() {
return udfClassName;
}
public void setUdfClassName(String udfClassName) {
this.udfClassName = udfClassName;
}
public boolean isOperator() {
return isOperator;
}
public void setOperator(boolean isOperator) {
this.isOperator = isOperator;
}
public Class<? extends UDF> getUdfClass() {
try {
return (Class<? extends UDF>) Class.forName(udfClassName, true, JavaUtils.getClassLoader());
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
try {
udf = (UDF) Class.forName(udfClassName, true, JavaUtils.getClassLoader()).newInstance();
} catch (Exception e) {
throw new UDFArgumentException(
"The UDF implementation class '" + udfClassName
+ "' is not present in the class path");
}
// Resolve for the method based on argument types
ArrayList<TypeInfo> argumentTypeInfos = new ArrayList<TypeInfo>(
arguments.length);
for (ObjectInspector argument : arguments) {
argumentTypeInfos.add(TypeInfoUtils
.getTypeInfoFromObjectInspector(argument));
}
udfMethod = udf.getResolver().getEvalMethod(argumentTypeInfos);
udfMethod.setAccessible(true);
// Create parameter converters
conversionHelper = new ConversionHelper(udfMethod, arguments);
// Create the non-deferred realArgument
realArguments = new Object[arguments.length];
// Get the return ObjectInspector.
ObjectInspector returnOI = ObjectInspectorFactory
.getReflectionObjectInspector(udfMethod.getGenericReturnType(),
ObjectInspectorOptions.JAVA);
return returnOI;
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
assert (arguments.length == realArguments.length);
// Calculate all the arguments
for (int i = 0; i < realArguments.length; i++) {
realArguments[i] = arguments[i].get();
}
// Call the function
Object result = FunctionRegistry.invoke(udfMethod, udf, conversionHelper
.convertIfNecessary(realArguments));
// For non-generic UDF, type info isn't available. This poses a problem for Hive Decimal.
// If the returned value is HiveDecimal, we assume maximum precision/scale.
if (result != null && result instanceof HiveDecimalWritable) {
result = HiveDecimalUtils.enforcePrecisionScale((HiveDecimalWritable) result,
HiveDecimal.SYSTEM_DEFAULT_PRECISION, HiveDecimal.SYSTEM_DEFAULT_SCALE);
}
return result;
}
@Override
public String getDisplayString(String[] children) {
if (isOperator) {
if (children.length == 1) {
// Prefix operator
return "(" + udfName + " " + children[0] + ")";
} else {
// Infix operator
assert children.length == 2;
return "(" + children[0] + " " + udfName + " " + children[1] + ")";
}
} else {
StringBuilder sb = new StringBuilder();
sb.append(udfName);
sb.append("(");
for (int i = 0; i < children.length; i++) {
sb.append(children[i]);
if (i + 1 < children.length) {
sb.append(", ");
}
}
sb.append(")");
return sb.toString();
}
}
@Override
public String[] getRequiredJars() {
return udf.getRequiredJars();
}
@Override
public String[] getRequiredFiles() {
return udf.getRequiredFiles();
}
}