/** * Copyright 2006 The Apache Software Foundation * * Licensed 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.mapred;import java.io.IOException;import java.io.File;import org.apache.hadoop.fs.FileSystem;/** A base class for {@link OutputFormat}. */public abstract class OutputFormatBase implements OutputFormat {  public abstract RecordWriter getRecordWriter(FileSystem fs,                                               JobConf job, String name)    throws IOException;  public void checkOutputSpecs(FileSystem fs, JobConf job) throws IOException {    // Ensure that the output directory is set and not already there    File outDir = job.getOutputDir();    if (outDir == null && job.getNumReduceTasks() != 0) {      throw new IOException("Output directory not set in JobConf.");    }    if (outDir != null && fs.exists(outDir)) {      throw new IOException("Output directory " + outDir +                             " already exists.");    }  }}