Lucene example source code file (ChecksumIndexInput.java)

This example Lucene source code file (ChecksumIndexInput.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

checksum, checksumindexinput, checksumindexinput, crc32, indexinput, indexinput, io, ioexception, ioexception, override, override, runtimeexception, zip

The Lucene ChecksumIndexInput.java source code

package org.apache.lucene.store;

/**
 * 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.zip.CRC32;
import java.util.zip.Checksum;

/** Writes bytes through to a primary IndexOutput, computing
 *  checksum as it goes. Note that you cannot use seek().
 *
 * @lucene.internal
 */
public class ChecksumIndexInput extends IndexInput {
  IndexInput main;
  Checksum digest;

  public ChecksumIndexInput(IndexInput main) {
    this.main = main;
    digest = new CRC32();
  }

  @Override
  public byte readByte() throws IOException {
    final byte b = main.readByte();
    digest.update(b);
    return b;
  }

  @Override
  public void readBytes(byte[] b, int offset, int len)
    throws IOException {
    main.readBytes(b, offset, len);
    digest.update(b, offset, len);
  }

  
  public long getChecksum() {
    return digest.getValue();
  }

  @Override
  public void close() throws IOException {
    main.close();
  }

  @Override
  public long getFilePointer() {
    return main.getFilePointer();
  }

  @Override
  public void seek(long pos) {
    throw new RuntimeException("not allowed");
  }

  @Override
  public long length() {
    return main.length();
  }
}