| /* |
| * 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.pig; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.mapreduce.InputFormat; |
| import org.apache.hadoop.mapreduce.Job; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigSplit; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.util.Utils; |
| |
| /** |
| * Convenience class to extend when decorating a LoadFunc. Subclasses must call the setLoadFunc |
| * with an instance of LoadFunc before other methods can be called. Not doing so will |
| * result in an IllegalArgumentException when the method is called. |
| */ |
| public class LoadFuncWrapper extends LoadFunc { |
| |
| private LoadFunc loadFunc; |
| |
| protected LoadFuncWrapper() {} |
| |
| /** |
| * The wrapped LoadFunc object must be set before method calls are made on this object. |
| * Typically, this is done with via constructor, but often times the wrapped object can |
| * not be properly initialized until later in the lifecycle of the wrapper object. |
| * @param loadFunc |
| */ |
| protected void setLoadFunc(LoadFunc loadFunc) { |
| this.loadFunc = loadFunc; |
| } |
| |
| @Override |
| public String relativeToAbsolutePath(String location, Path curDir) throws IOException { |
| return loadFunc().relativeToAbsolutePath(location, curDir); |
| } |
| |
| @Override |
| public void setLocation(String location, Job job) throws IOException { |
| loadFunc().setLocation(location, job); |
| } |
| |
| @Override |
| public InputFormat getInputFormat() throws IOException { |
| return loadFunc().getInputFormat(); |
| } |
| |
| @Override |
| public LoadCaster getLoadCaster() throws IOException { |
| return loadFunc().getLoadCaster(); |
| } |
| |
| @Override |
| public void prepareToRead(RecordReader reader, PigSplit split) throws IOException { |
| loadFunc().prepareToRead(reader, split); |
| } |
| |
| @Override |
| public Tuple getNext() throws IOException { |
| return loadFunc().getNext(); |
| } |
| |
| @Override |
| public void setUDFContextSignature(String signature) { |
| loadFunc().setUDFContextSignature(signature); |
| } |
| |
| protected LoadFunc loadFunc() { |
| if (this.loadFunc == null) { |
| // Pig does not re-throw the exception with a stack trace in the parse phase. |
| throw new IllegalArgumentException("Method calls can not be made on the " + |
| "LoadFuncWrapper object before the wrapped LoadFunc object has been " |
| + "set. Failed on method call " + getMethodName(1)); |
| } |
| return loadFunc; |
| } |
| |
| /** |
| * Returns a method in the call stack at the given depth. Depth 0 will return the method that |
| * called this getMethodName, depth 1 the method that called it, etc... |
| * @param depth |
| * @return method name as String |
| */ |
| protected String getMethodName(final int depth) { |
| final StackTraceElement[] ste = Thread.currentThread().getStackTrace(); |
| int index; |
| if (Utils.isVendorIBM()) { |
| index = 3 + depth; |
| } else { |
| index = 2 + depth; |
| } |
| return ste[index].getMethodName(); |
| } |
| |
| } |