segmentreader.java

lucene-2.4.0 是一个全文收索的工具包

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 java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.search.DefaultSimilarity;
import org.apache.lucene.store.BufferedIndexInput;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.util.BitVector;
import org.apache.lucene.util.CloseableThreadLocal;

/**
 * @version $Id: SegmentReader.java 695184 2008-09-14 10:32:59Z mikemccand $
 */
class SegmentReader extends DirectoryIndexReader {
  private String segment;
  private SegmentInfo si;
  private int readBufferSize;

  FieldInfos fieldInfos;
  private FieldsReader fieldsReader;

  TermInfosReader tis;
  TermVectorsReader termVectorsReaderOrig = null;
  CloseableThreadLocal termVectorsLocal = new CloseableThreadLocal();

  BitVector deletedDocs = null;
  private boolean deletedDocsDirty = false;
  private boolean normsDirty = false;
  private boolean undeleteAll = false;
  private int pendingDeleteCount;

  private boolean rollbackDeletedDocsDirty = false;
  private boolean rollbackNormsDirty = false;
  private boolean rollbackUndeleteAll = false;
  private int rollbackPendingDeleteCount;
  private boolean readOnly;

  IndexInput freqStream;
  IndexInput proxStream;

  // optionally used for the .nrm file shared by multiple norms
  private IndexInput singleNormStream;

  // Compound File Reader when based on a compound file segment
  CompoundFileReader cfsReader = null;
  CompoundFileReader storeCFSReader = null;
  
  // indicates the SegmentReader with which the resources are being shared,
  // in case this is a re-opened reader
  private SegmentReader referencedSegmentReader = null;
  
  private class Norm {
    volatile int refCount;
    boolean useSingleNormStream;
    
    public synchronized void incRef() {
      assert refCount > 0;
      refCount++;
    }

    public synchronized void decRef() throws IOException {
      assert refCount > 0;
      if (refCount == 1) {
        close();
      }
      refCount--;

    }
    
    public Norm(IndexInput in, boolean useSingleNormStream, int number, long normSeek)
    {
      refCount = 1;
      this.in = in;
      this.number = number;
      this.normSeek = normSeek;
      this.useSingleNormStream = useSingleNormStream;
    }

    private IndexInput in;
    private byte[] bytes;
    private boolean dirty;
    private int number;
    private long normSeek;
    private boolean rollbackDirty;

    private void reWrite(SegmentInfo si) throws IOException {
      // NOTE: norms are re-written in regular directory, not cfs
      si.advanceNormGen(this.number);
      IndexOutput out = directory().createOutput(si.getNormFileName(this.number));
      try {
        out.writeBytes(bytes, maxDoc());
      } finally {
        out.close();
      }
      this.dirty = false;
    }
    
    /** Closes the underlying IndexInput for this norm.
     * It is still valid to access all other norm properties after close is called.
     * @throws IOException
     */
    private synchronized void close() throws IOException {
      if (in != null && !useSingleNormStream) {
        in.close();
      }
      in = null;
    }
  }
  
  /**
   * Increments the RC of this reader, as well as
   * of all norms this reader is using
   */
  public synchronized void incRef() {
    super.incRef();
    Iterator it = norms.values().iterator();
    while (it.hasNext()) {
      Norm norm = (Norm) it.next();
      norm.incRef();
    }
  }
  
  /**
   * only increments the RC of this reader, not tof 
   * he norms. This is important whenever a reopen()
   * creates a new SegmentReader that doesn't share
   * the norms with this one 
   */
  private synchronized void incRefReaderNotNorms() {
    super.incRef();
  }

  public synchronized void decRef() throws IOException {
    super.decRef();
    Iterator it = norms.values().iterator();
    while (it.hasNext()) {
      Norm norm = (Norm) it.next();
      norm.decRef();
    }
  }
  
  private synchronized void decRefReaderNotNorms() throws IOException {
    super.decRef();
  }
  
  Map norms = new HashMap();
  
  /** The class which implements SegmentReader. */
  private static Class IMPL;
  static {
    try {
      String name =
        System.getProperty("org.apache.lucene.SegmentReader.class",
                           SegmentReader.class.getName());
      IMPL = Class.forName(name);
    } catch (ClassNotFoundException e) {
      throw new RuntimeException("cannot load SegmentReader class: " + e, e);
    } catch (SecurityException se) {
      try {
        IMPL = Class.forName(SegmentReader.class.getName());
      } catch (ClassNotFoundException e) {
        throw new RuntimeException("cannot load default SegmentReader class: " + e, e);
      }
    }
  }

  private static Class READONLY_IMPL;
  static {
    try {
      String name =
        System.getProperty("org.apache.lucene.ReadOnlySegmentReader.class",
                           ReadOnlySegmentReader.class.getName());
      READONLY_IMPL = Class.forName(name);
    } catch (ClassNotFoundException e) {
      throw new RuntimeException("cannot load ReadOnlySegmentReader class: " + e, e);
    } catch (SecurityException se) {
      try {
        READONLY_IMPL = Class.forName(ReadOnlySegmentReader.class.getName());
      } catch (ClassNotFoundException e) {
        throw new RuntimeException("cannot load default ReadOnlySegmentReader class: " + e, e);
      }
    }
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(SegmentInfo si) throws CorruptIndexException, IOException {
    return get(READ_ONLY_DEFAULT, si.dir, si, null, false, false, BufferedIndexInput.BUFFER_SIZE, true);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(boolean readOnly, SegmentInfo si) throws CorruptIndexException, IOException {
    return get(readOnly, si.dir, si, null, false, false, BufferedIndexInput.BUFFER_SIZE, true);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  static SegmentReader get(SegmentInfo si, boolean doOpenStores) throws CorruptIndexException, IOException {
    return get(READ_ONLY_DEFAULT, si.dir, si, null, false, false, BufferedIndexInput.BUFFER_SIZE, doOpenStores);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(SegmentInfo si, int readBufferSize) throws CorruptIndexException, IOException {
    return get(READ_ONLY_DEFAULT, si.dir, si, null, false, false, readBufferSize, true);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  static SegmentReader get(SegmentInfo si, int readBufferSize, boolean doOpenStores) throws CorruptIndexException, IOException {
    return get(READ_ONLY_DEFAULT, si.dir, si, null, false, false, readBufferSize, doOpenStores);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  static SegmentReader get(boolean readOnly, SegmentInfo si, int readBufferSize, boolean doOpenStores) throws CorruptIndexException, IOException {
    return get(readOnly, si.dir, si, null, false, false, readBufferSize, doOpenStores);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(boolean readOnly, SegmentInfos sis, SegmentInfo si,
                                  boolean closeDir) throws CorruptIndexException, IOException {
    return get(readOnly, si.dir, si, sis, closeDir, true, BufferedIndexInput.BUFFER_SIZE, true);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(Directory dir, SegmentInfo si,
                                  SegmentInfos sis,
                                  boolean closeDir, boolean ownDir,
                                  int readBufferSize)
    throws CorruptIndexException, IOException {
    return get(READ_ONLY_DEFAULT, dir, si, sis, closeDir, ownDir, readBufferSize, true);
  }

  /**
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public static SegmentReader get(boolean readOnly,
                                  Directory dir,
                                  SegmentInfo si,
                                  SegmentInfos sis,
                                  boolean closeDir, boolean ownDir,
                                  int readBufferSize,
                                  boolean doOpenStores)
    throws CorruptIndexException, IOException {
    SegmentReader instance;
    try {
      if (readOnly)
        instance = (SegmentReader)READONLY_IMPL.newInstance();
      else
        instance = (SegmentReader)IMPL.newInstance();
    } catch (Exception e) {
      throw new RuntimeException("cannot load SegmentReader class: " + e, e);
    }
    instance.init(dir, sis, closeDir, readOnly);
    instance.initialize(si, readBufferSize, doOpenStores);
    return instance;
  }

  private void initialize(SegmentInfo si, int readBufferSize, boolean doOpenStores) throws CorruptIndexException, IOException {
    segment = si.name;
    this.si = si;
    this.readBufferSize = readBufferSize;

    boolean success = false;

    try {
      // Use compound file directory for some files, if it exists
      Directory cfsDir = directory();
      if (si.getUseCompoundFile()) {
        cfsReader = new CompoundFileReader(directory(), segment + "." + IndexFileNames.COMPOUND_FILE_EXTENSION, readBufferSize);
        cfsDir = cfsReader;
      }

      final Directory storeDir;

      if (doOpenStores) {
        if (si.getDocStoreOffset() != -1) {
          if (si.getDocStoreIsCompoundFile()) {
            storeCFSReader = new CompoundFileReader(directory(), si.getDocStoreSegment() + "." + IndexFileNames.COMPOUND_FILE_STORE_EXTENSION, readBufferSize);
            storeDir = storeCFSReader;
          } else {
            storeDir = directory();
          }
        } else {
          storeDir = cfsDir;
        }
      } else
        storeDir = null;

      fieldInfos = new FieldInfos(cfsDir, segment + ".fnm");

      boolean anyProx = false;
      final int numFields = fieldInfos.size();
      for(int i=0;!anyProx && i<numFields;i++)
        if (!fieldInfos.fieldInfo(i).omitTf)
          anyProx = true;

      final String fieldsSegment;

      if (si.getDocStoreOffset() != -1)
        fieldsSegment = si.getDocStoreSegment();
      else
        fieldsSegment = segment;

      if (doOpenStores) {
        fieldsReader = new FieldsReader(storeDir, fieldsSegment, fieldInfos, readBufferSize,
                                        si.getDocStoreOffset(), si.docCount);

        // Verify two sources of "maxDoc" agree:
        if (si.getDocStoreOffset() == -1 && fieldsReader.size() != si.docCount) {
          throw new CorruptIndexException("doc counts differ for segment " + si.name + ": fieldsReader shows " + fieldsReader.size() + " but segmentInfo shows " + si.docCount);
        }
      }

      tis = new TermInfosReader(cfsDir, segment, fieldInfos, readBufferSize);
      
      loadDeletedDocs();

      // make sure that all index files have been read or are kept open
      // so that if an index update removes them we'll still have them