segmentinfos.java

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package org.apache.lucene.index;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Lucene" must not be used to endorse or promote products
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 * 5. Products derived from this software may not be called "Apache",
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
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import java.util.Vector;
import java.io.IOException;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.InputStream;
import org.apache.lucene.store.OutputStream;

final class SegmentInfos extends Vector {
  public int counter = 0;			  // used to name new segments
  
  public final SegmentInfo info(int i) {
    return (SegmentInfo)elementAt(i);
  }

  public final void read(Directory directory) throws IOException {
    InputStream input = directory.openFile("segments");
    try {
      counter = input.readInt();		  // read counter
      for (int i = input.readInt(); i > 0; i--) { // read segmentInfos
	SegmentInfo si = new SegmentInfo(input.readString(), input.readInt(),
					 directory);
	addElement(si);
      }
    } finally {
      input.close();
    }
  }

  public final void write(Directory directory) throws IOException {
    OutputStream output = directory.createFile("segments.new");
    try {
      output.writeInt(counter);			  // write counter
      output.writeInt(size());			  // write infos
      for (int i = 0; i < size(); i++) {
	SegmentInfo si = info(i);
	output.writeString(si.name);
	output.writeInt(si.docCount);
      }
    } finally {
      output.close();
    }

    // install new segment info
    directory.renameFile("segments.new", "segments");
  }
}