Lucene example source code file (StoredFieldsWriter.java)

This example Lucene source code file (StoredFieldsWriter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

documentswriter, fieldinfos, fieldinfos, fieldswriter, io, ioexception, ioexception, override, override, perdoc, perdoc, ramoutputstream, storedfieldswriter, storedfieldswriterperthread, string

The Lucene StoredFieldsWriter.java source code

package org.apache.lucene.index;

/**
 * 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.
 */

import java.io.IOException;
import org.apache.lucene.store.RAMOutputStream;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.RamUsageEstimator;

/** This is a DocFieldConsumer that writes stored fields. */
final class StoredFieldsWriter {

  FieldsWriter fieldsWriter;
  final DocumentsWriter docWriter;
  final FieldInfos fieldInfos;
  int lastDocID;

  PerDoc[] docFreeList = new PerDoc[1];
  int freeCount;

  public StoredFieldsWriter(DocumentsWriter docWriter, FieldInfos fieldInfos) {
    this.docWriter = docWriter;
    this.fieldInfos = fieldInfos;
  }

  public StoredFieldsWriterPerThread addThread(DocumentsWriter.DocState docState) throws IOException {
    return new StoredFieldsWriterPerThread(docState, this);
  }

  synchronized public void flush(SegmentWriteState state) throws IOException {
    if (state.numDocs > lastDocID) {
      initFieldsWriter();
      fill(state.numDocs);
    }

    if (fieldsWriter != null) {
      fieldsWriter.close();
      fieldsWriter = null;
      lastDocID = 0;

      String fieldsIdxName = IndexFileNames.segmentFileName(state.segmentName, IndexFileNames.FIELDS_INDEX_EXTENSION);
      if (4 + ((long) state.numDocs) * 8 != state.directory.fileLength(fieldsIdxName)) {
        throw new RuntimeException("after flush: fdx size mismatch: " + state.numDocs + " docs vs " + state.directory.fileLength(fieldsIdxName) + " length in bytes of " + fieldsIdxName + " file exists?=" + state.directory.fileExists(fieldsIdxName));
      }
    }
  }

  private synchronized void initFieldsWriter() throws IOException {
    if (fieldsWriter == null) {
      fieldsWriter = new FieldsWriter(docWriter.directory, docWriter.getSegment(), fieldInfos);
      lastDocID = 0;
    }
  }

  int allocCount;

  synchronized PerDoc getPerDoc() {
    if (freeCount == 0) {
      allocCount++;
      if (allocCount > docFreeList.length) {
        // Grow our free list up front to make sure we have
        // enough space to recycle all outstanding PerDoc
        // instances
        assert allocCount == 1+docFreeList.length;
        docFreeList = new PerDoc[ArrayUtil.oversize(allocCount, RamUsageEstimator.NUM_BYTES_OBJECT_REF)];
      }
      return new PerDoc();
    } else {
      return docFreeList[--freeCount];
    }
  }

  synchronized void abort() {
    if (fieldsWriter != null) {
      fieldsWriter.abort();
      fieldsWriter = null;
      lastDocID = 0;
    }
  }

  /** Fills in any hole in the docIDs */
  void fill(int docID) throws IOException {
    // We must "catch up" for all docs before us
    // that had no stored fields:
    while(lastDocID < docID) {
      fieldsWriter.skipDocument();
      lastDocID++;
    }
  }

  synchronized void finishDocument(PerDoc perDoc) throws IOException {
    assert docWriter.writer.testPoint("StoredFieldsWriter.finishDocument start");
    initFieldsWriter();

    fill(perDoc.docID);

    // Append stored fields to the real FieldsWriter:
    fieldsWriter.flushDocument(perDoc.numStoredFields, perDoc.fdt);
    lastDocID++;
    perDoc.reset();
    free(perDoc);
    assert docWriter.writer.testPoint("StoredFieldsWriter.finishDocument end");
  }

  synchronized void free(PerDoc perDoc) {
    assert freeCount < docFreeList.length;
    assert 0 == perDoc.numStoredFields;
    assert 0 == perDoc.fdt.length();
    assert 0 == perDoc.fdt.getFilePointer();
    docFreeList[freeCount++] = perDoc;
  }

  class PerDoc extends DocumentsWriter.DocWriter {
    final DocumentsWriter.PerDocBuffer buffer = docWriter.newPerDocBuffer();
    RAMOutputStream fdt = new RAMOutputStream(buffer);
    int numStoredFields;

    void reset() {
      fdt.reset();
      buffer.recycle();
      numStoredFields = 0;
    }

    @Override
    void abort() {
      reset();
      free(this);
    }

    @Override
    public long sizeInBytes() {
      return buffer.getSizeInBytes();
    }

    @Override
    public void finish() throws IOException {
      finishDocument(this);
    }
  }
}