Java tutorial
/** * 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 com.sensei.indexing.hadoop.keyvalueformat; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.Writable; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.document.Document; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.IndexWriter.MaxFieldLength; import org.apache.lucene.index.KeepOnlyLastCommitDeletionPolicy; import org.apache.lucene.store.Directory; import org.apache.lucene.store.RAMDirectory; import org.apache.lucene.store.RAMDirectorySerializer; import com.sensei.indexing.hadoop.reduce.RAMDirectoryUtil; import com.sensei.indexing.hadoop.util.SenseiJobConfig; /** * An intermediate form for one or more parsed Lucene documents and/or * delete terms. It actually uses Lucene file format as the format for * the intermediate form by using RAM dir files. * * Note: If process(*) is ever called, closeWriter() should be called. * Otherwise, no need to call closeWriter(). */ public class IntermediateForm implements Writable { private Configuration conf = null; private RAMDirectory dir; private IndexWriter writer; private int numDocs; /** * Constructor * @throws IOException */ public IntermediateForm() throws IOException { dir = new RAMDirectory(); writer = null; numDocs = 0; } /** * Configure using an index update configuration. * @param iconf the index update configuration */ public void configure(Configuration iconf) { this.conf = iconf; } /** * Get the ram directory of the intermediate form. * @return the ram directory */ public Directory getDirectory() { return dir; } /** * This method is used by the index update mapper and process a document * operation into the current intermediate form. * @param doc input document operation * @param analyzer the analyzer * @throws IOException */ public void process(Document doc, Analyzer analyzer) throws IOException { if (writer == null) { // analyzer is null because we specify an analyzer with addDocument writer = createWriter(); } writer.addDocument(doc, analyzer); numDocs++; } /** * This method is used by the index update combiner and process an * intermediate form into the current intermediate form. More specifically, * the input intermediate forms are a single-document ram index and/or a * single delete term. * @param form the input intermediate form * @throws IOException */ public void process(IntermediateForm form) throws IOException { if (form.dir.sizeInBytes() > 0) { if (writer == null) { writer = createWriter(); } writer.addIndexesNoOptimize(new Directory[] { form.dir }); numDocs++; } } /** * Close the Lucene index writer associated with the intermediate form, * if created. Do not close the ram directory. In fact, there is no need * to close a ram directory. * @throws IOException */ public void closeWriter() throws IOException { if (writer != null) { writer.optimize(); writer.close(); writer = null; } } /** * The total size of files in the directory and ram used by the index writer. * It does not include memory used by the delete list. * @return the total size in bytes */ public long totalSizeInBytes() throws IOException { long size = dir.sizeInBytes(); if (writer != null) { size += writer.ramSizeInBytes(); } return size; } /* (non-Javadoc) * @see java.lang.Object#toString() */ public String toString() { StringBuilder buffer = new StringBuilder(); buffer.append(this.getClass().getSimpleName()); buffer.append("[numDocs="); buffer.append(numDocs); buffer.append(", numDeletes="); buffer.append("]"); return buffer.toString(); } private IndexWriter createWriter() throws IOException { IndexWriter writer = // new IndexWriter(dir, false, null, new KeepOnlyLastCommitDeletionPolicy()); new IndexWriter(dir, null, new KeepOnlyLastCommitDeletionPolicy(), MaxFieldLength.UNLIMITED); writer.setUseCompoundFile(true); //use compound file fortmat to speed up; if (conf != null) { int maxFieldLength = conf.getInt(SenseiJobConfig.MAX_FIELD_LENGTH, -1); if (maxFieldLength > 0) { writer.setMaxFieldLength(maxFieldLength); } } return writer; } private void resetForm() throws IOException { if (dir.sizeInBytes() > 0) { // it's ok if we don't close a ram directory dir.close(); // an alternative is to delete all the files and reuse the ram directory dir = new RAMDirectory(); } assert (writer == null); numDocs = 0; } // /////////////////////////////////// // Writable // /////////////////////////////////// /* (non-Javadoc) * @see org.apache.hadoop.io.Writable#write(java.io.DataOutput) */ public void write(DataOutput out) throws IOException { String[] files = dir.listAll(); RAMDirectoryUtil.writeRAMFiles(out, dir, files); // RAMDirectorySerializer.toDataOutput(out, dir); } /* (non-Javadoc) * @see org.apache.hadoop.io.Writable#readFields(java.io.DataInput) */ public void readFields(DataInput in) throws IOException { resetForm(); RAMDirectoryUtil.readRAMFiles(in, dir); // numDocs = 0; // dir = RAMDirectorySerializer.fromDataInput(in); } }