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Lucene example source code file (MockIndexOutputWrapper.java)

This example Lucene source code file (MockIndexOutputWrapper.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

indexoutput, indexoutput, io, ioexception, ioexception, mockdirectorywrapper, mockindexoutputwrapper, mockramdirectory, override, override, string, string

The Lucene MockIndexOutputWrapper.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 org.apache.lucene.util.LuceneTestCase;

/**
 * Used by MockRAMDirectory to create an output stream that
 * will throw an IOException on fake disk full, track max
 * disk space actually used, and maybe throw random
 * IOExceptions.
 */

public class MockIndexOutputWrapper extends IndexOutput {
  private MockDirectoryWrapper dir;
  private final IndexOutput delegate;
  private boolean first=true;
  final String name;
  
  byte[] singleByte = new byte[1];

  /** Construct an empty output buffer. */
  public MockIndexOutputWrapper(MockDirectoryWrapper dir, IndexOutput delegate, String name) {
    this.dir = dir;
    this.name = name;
    this.delegate = delegate;
  }

  @Override
  public void close() throws IOException {
    try {
      dir.maybeThrowDeterministicException();
    } finally {
      delegate.close();
      if (dir.trackDiskUsage) {
        // Now compute actual disk usage & track the maxUsedSize
        // in the MockDirectoryWrapper:
        long size = dir.getRecomputedActualSizeInBytes();
        if (size > dir.maxUsedSize) {
          dir.maxUsedSize = size;
        }
      }
      dir.removeIndexOutput(this, name);
    }
  }

  @Override
  public void flush() throws IOException {
    dir.maybeThrowDeterministicException();
    delegate.flush();
  }

  @Override
  public void writeByte(byte b) throws IOException {
    singleByte[0] = b;
    writeBytes(singleByte, 0, 1);
  }
  
  @Override
  public void writeBytes(byte[] b, int offset, int len) throws IOException {
    long freeSpace = dir.maxSize == 0 ? 0 : dir.maxSize - dir.sizeInBytes();
    long realUsage = 0;

    // If MockRAMDir crashed since we were opened, then
    // don't write anything:
    if (dir.crashed)
      throw new IOException("MockRAMDirectory was crashed; cannot write to " + name);

    // Enforce disk full:
    if (dir.maxSize != 0 && freeSpace <= len) {
      // Compute the real disk free.  This will greatly slow
      // down our test but makes it more accurate:
      realUsage = dir.getRecomputedActualSizeInBytes();
      freeSpace = dir.maxSize - realUsage;
    }

    if (dir.maxSize != 0 && freeSpace <= len) {
      if (freeSpace > 0) {
        realUsage += freeSpace;
        delegate.writeBytes(b, offset, (int) freeSpace);
      }
      if (realUsage > dir.maxUsedSize) {
        dir.maxUsedSize = realUsage;
      }
      String message = "fake disk full at " + dir.getRecomputedActualSizeInBytes() + " bytes when writing " + name + " (file length=" + delegate.length();
      if (freeSpace > 0) {
        message += "; wrote " + freeSpace + " of " + len + " bytes";
      }
      message += ")";
      if (LuceneTestCase.VERBOSE) {
        System.out.println(Thread.currentThread().getName() + ": MDW: now throw fake disk full");
        new Throwable().printStackTrace(System.out);
      }
      throw new IOException(message);
    } else {
      if (dir.randomState.nextInt(200) == 0) {
        final int half = len/2;
        delegate.writeBytes(b, offset, half);
        Thread.yield();
        delegate.writeBytes(b, offset+half, len-half);
      } else {
        delegate.writeBytes(b, offset, len);
      }
    }

    dir.maybeThrowDeterministicException();

    if (first) {
      // Maybe throw random exception; only do this on first
      // write to a new file:
      first = false;
      dir.maybeThrowIOException();
    }
  }

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

  @Override
  public void seek(long pos) throws IOException {
    delegate.seek(pos);
  }

  @Override
  public long length() throws IOException {
    return delegate.length();
  }

  @Override
  public void setLength(long length) throws IOException {
    delegate.setLength(length);
  }

  @Override
  public void copyBytes(DataInput input, long numBytes) throws IOException {
    delegate.copyBytes(input, numBytes);
    // TODO: we may need to check disk full here as well
    dir.maybeThrowDeterministicException();
  }
}

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