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Lucene example source code file (StreamUtils.java)

This example Lucene source code file (StreamUtils.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

buffer_size, compressorexception, fileoutputstream, inputstream, inputstream, io, ioexception, ioexception, outputstream, override, override, plain, string, type, type, util

The Lucene StreamUtils.java source code

package org.apache.lucene.benchmark.byTask.utils;

/**
 * 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.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import org.apache.commons.compress.compressors.CompressorException;
import org.apache.commons.compress.compressors.CompressorStreamFactory;

/**
 * Stream utilities.
 */
public class StreamUtils {

	/** Buffer size used across the benchmark package */
	public static final int BUFFER_SIZE = 1 << 16; // 64K
	
	/** File format type */
	public enum Type {
		/** BZIP2 is automatically used for <b>.bz2 and .bzip2 extensions. */
		BZIP2(CompressorStreamFactory.BZIP2),
		/** GZIP is automatically used for <b>.gz and .gzip extensions. */
		GZIP(CompressorStreamFactory.GZIP),
		/** Plain text is used for anything which is not GZIP or BZIP. */
		PLAIN(null);
		private final String csfType;
		Type(String csfType) {
			this.csfType = csfType;
		}
		private InputStream inputStream(InputStream in) throws IOException {
			try {
				return csfType==null ? in : closableCompressorInputStream(this, in);
			} catch (CompressorException e) {
    		IOException ioe = new IOException(e.getMessage());
    		ioe.initCause(e);
    		throw ioe;			}  
		}
		private OutputStream outputStream(OutputStream os) throws IOException {
			try {
				return csfType==null ? os : new CompressorStreamFactory().createCompressorOutputStream(csfType, os);
			} catch (CompressorException e) {
				IOException ioe = new IOException(e.getMessage());
				ioe.initCause(e);
				throw ioe;  
			}  
		}
	}
	
  private static final Map<String,Type> extensionToType = new HashMap();
  static {
  	// these in are lower case, we will lower case at the test as well
    extensionToType.put(".bz2", Type.BZIP2);
    extensionToType.put(".bzip", Type.BZIP2);
    extensionToType.put(".gz", Type.GZIP);
    extensionToType.put(".gzip", Type.GZIP);
  }
  
  
  /**
   * Returns an {@link InputStream} over the requested file. This method
   * attempts to identify the appropriate {@link InputStream} instance to return
   * based on the file name (e.g., if it ends with .bz2 or .bzip, return a
   * 'bzip' {@link InputStream}).
   */
  public static InputStream inputStream(File file) throws IOException {
    // First, create a FileInputStream, as this will be required by all types.
    // Wrap with BufferedInputStream for better performance
    InputStream in = new BufferedInputStream(new FileInputStream(file), BUFFER_SIZE);
    return fileType(file).inputStream(in);
  }

  /** Return the type of the file, or null if unknown */
  private static Type fileType(File file) {
  	Type type = null;
    String fileName = file.getName();
    int idx = fileName.lastIndexOf('.');
    if (idx != -1) {
      type = extensionToType.get(fileName.substring(idx).toLowerCase(Locale.ENGLISH));
    }
    return type==null ? Type.PLAIN : type;
	}
  
  /**
   * Wrap the compressor input stream so that calling close will also close
   * the underlying stream - workaround for CommonsCompress bug (COMPRESS-127). 
   */
  private static InputStream closableCompressorInputStream(Type type, final InputStream is) throws CompressorException {
    final InputStream delegee = new CompressorStreamFactory().createCompressorInputStream(type.csfType, is);
    if (!Type.GZIP.equals(type)) {
      return delegee; //compressor bug affects only gzip
    }
    return new InputStream() {
			@Override	public int read() throws IOException { return delegee.read();	}
			@Override	public int read(byte[] b) throws IOException { return delegee.read(b);	}
			@Override	public int available() throws IOException {	return delegee.available();	}
			@Override	public synchronized void mark(int readlimit) { delegee.mark(readlimit);	}
			@Override	public boolean markSupported() { return delegee.markSupported(); }
			@Override	public int read(byte[] b, int off, int len) throws IOException { return delegee.read(b, off, len); }
			@Override	public synchronized void reset() throws IOException {	delegee.reset(); }
			@Override	public long skip(long n) throws IOException {	return delegee.skip(n);	}
			@Override	
			public void close() throws IOException { 
				delegee.close();
				is.close();
			}
    };
	}

  /**
   * Returns an {@link OutputStream} over the requested file, identifying
   * the appropriate {@link OutputStream} instance similar to {@link #inputStream(File)}.
   */
  public static OutputStream outputStream(File file) throws IOException {
    // First, create a FileInputStream, as this will be required by all types.
    // Wrap with BufferedInputStream for better performance
    OutputStream os = new BufferedOutputStream(new FileOutputStream(file), BUFFER_SIZE);
    return fileType(file).outputStream(os);
  }
}

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