lucene/core/src/java/org/apache/lucene/util/IOUtils.java - lucene-solr - Git at Google

 package org.apache.lucene.util;

 /*
  * 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.BufferedReader;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.nio.charset.CodingErrorAction;

 import org.apache.lucene.store.Directory;

 /** This class emulates the new Java 7 "Try-With-Resources" statement.
  * Remove once Lucene is on Java 7.
  * @lucene.internal */
 public final class IOUtils {

   /**
    * UTF-8 charset string
    * @see Charset#forName(String)
    */
   public static final String UTF_8 = "UTF-8";

   /**
    * UTF-8 {@link Charset} instance to prevent repeated
    * {@link Charset#forName(String)} lookups
    */
   public static final Charset CHARSET_UTF_8 = Charset.forName("UTF-8");
   private IOUtils() {} // no instance

   /**
    * <p>Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions. Some of the <tt>Closeable</tt>s
    * may be null, they are ignored. After everything is closed, method either throws <tt>priorException</tt>,
    * if one is supplied, or the first of suppressed exceptions, or completes normally.</p>
    * <p>Sample usage:<br/>
    * <pre class="prettyprint">
    * Closeable resource1 = null, resource2 = null, resource3 = null;
    * ExpectedException priorE = null;
    * try {
    *   resource1 = ...; resource2 = ...; resource3 = ...; // Acquisition may throw ExpectedException
    *   ..do..stuff.. // May throw ExpectedException
    * } catch (ExpectedException e) {
    *   priorE = e;
    * } finally {
    *   closeWhileHandlingException(priorE, resource1, resource2, resource3);
    * }
    * </pre>
    * </p>
    * @param priorException  <tt>null</tt> or an exception that will be rethrown after method completion
    * @param objects         objects to call <tt>close()</tt> on
    */
   public static <E extends Exception> void closeWhileHandlingException(E priorException, Closeable... objects) throws E, IOException {
     Throwable th = null;

     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
         addSuppressed((priorException == null) ? th : priorException, t);
         if (th == null) {
           th = t;
         }
       }
     }

     if (priorException != null) {
       throw priorException;
     } else {
       reThrow(th);
     }
   }

   /**
    * Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
    * @see #closeWhileHandlingException(Exception, Closeable...) */
   public static <E extends Exception> void closeWhileHandlingException(E priorException, Iterable<? extends Closeable> objects) throws E, IOException {
     Throwable th = null;

     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
         addSuppressed((priorException == null) ? th : priorException, t);
         if (th == null) {
           th = t;
         }
       }
     }

     if (priorException != null) {
       throw priorException;
     } else {
       reThrow(th);
     }
   }

   /**
    * Closes all given <tt>Closeable</tt>s.  Some of the
    * <tt>Closeable</tt>s may be null; they are
    * ignored.  After everything is closed, the method either
    * throws the first exception it hit while closing, or
    * completes normally if there were no exceptions.
    *
    * @param objects
    *          objects to call <tt>close()</tt> on
    */
   public static void close(Closeable... objects) throws IOException {
     Throwable th = null;

     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
         addSuppressed(th, t);
         if (th == null) {
           th = t;
         }
       }
     }

     reThrow(th);
   }

   /**
    * Closes all given <tt>Closeable</tt>s.
    * @see #close(Closeable...)
    */
   public static void close(Iterable<? extends Closeable> objects) throws IOException {
     Throwable th = null;

     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
         addSuppressed(th, t);
         if (th == null) {
           th = t;
         }
       }
     }

     reThrow(th);
   }

   /**
    * Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
    * Some of the <tt>Closeable</tt>s may be null, they are ignored.
    *
    * @param objects
    *          objects to call <tt>close()</tt> on
    */
   public static void closeWhileHandlingException(Closeable... objects) {
     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
       }
     }
   }

   /**
    * Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
    * @see #closeWhileHandlingException(Closeable...)
    */
   public static void closeWhileHandlingException(Iterable<? extends Closeable> objects) {
     for (Closeable object : objects) {
       try {
         if (object != null) {
           object.close();
         }
       } catch (Throwable t) {
       }
     }
   }

   /** adds a Throwable to the list of suppressed Exceptions of the first Throwable
    * @param exception this exception should get the suppressed one added
    * @param suppressed the suppressed exception
    */
   private static void addSuppressed(Throwable exception, Throwable suppressed) {
     if (exception != null && suppressed != null) {
       exception.addSuppressed(suppressed);
     }
   }

   /**
    * Wrapping the given {@link InputStream} in a reader using a {@link CharsetDecoder}.
    * Unlike Java's defaults this reader will throw an exception if your it detects
    * the read charset doesn't match the expected {@link Charset}.
    * <p>
    * Decoding readers are useful to load configuration files, stopword lists or synonym files
    * to detect character set problems. However, its not recommended to use as a common purpose
    * reader.
    *
    * @param stream the stream to wrap in a reader
    * @param charSet the expected charset
    * @return a wrapping reader
    */
   public static Reader getDecodingReader(InputStream stream, Charset charSet) {
     final CharsetDecoder charSetDecoder = charSet.newDecoder()
         .onMalformedInput(CodingErrorAction.REPORT)
         .onUnmappableCharacter(CodingErrorAction.REPORT);
     return new BufferedReader(new InputStreamReader(stream, charSetDecoder));
   }

   /**
    * Opens a Reader for the given {@link File} using a {@link CharsetDecoder}.
    * Unlike Java's defaults this reader will throw an exception if your it detects
    * the read charset doesn't match the expected {@link Charset}.
    * <p>
    * Decoding readers are useful to load configuration files, stopword lists or synonym files
    * to detect character set problems. However, its not recommended to use as a common purpose
    * reader.
    * @param file the file to open a reader on
    * @param charSet the expected charset
    * @return a reader to read the given file
    */
   public static Reader getDecodingReader(File file, Charset charSet) throws IOException {
     FileInputStream stream = null;
     boolean success = false;
     try {
       stream = new FileInputStream(file);
       final Reader reader = getDecodingReader(stream, charSet);
       success = true;
       return reader;

     } finally {
       if (!success) {
         IOUtils.close(stream);
       }
     }
   }

   /**
    * Opens a Reader for the given resource using a {@link CharsetDecoder}.
    * Unlike Java's defaults this reader will throw an exception if your it detects
    * the read charset doesn't match the expected {@link Charset}.
    * <p>
    * Decoding readers are useful to load configuration files, stopword lists or synonym files
    * to detect character set problems. However, its not recommended to use as a common purpose
    * reader.
    * @param clazz the class used to locate the resource
    * @param resource the resource name to load
    * @param charSet the expected charset
    * @return a reader to read the given file
    *
    */
   public static Reader getDecodingReader(Class<?> clazz, String resource, Charset charSet) throws IOException {
     InputStream stream = null;
     boolean success = false;
     try {
       stream = clazz
       .getResourceAsStream(resource);
       final Reader reader = getDecodingReader(stream, charSet);
       success = true;
       return reader;
     } finally {
       if (!success) {
         IOUtils.close(stream);
       }
     }
   }

   /**
    * Deletes all given files, suppressing all thrown IOExceptions.
    * <p>
    * Note that the files should not be null.
    */
   public static void deleteFilesIgnoringExceptions(Directory dir, String... files) {
     for (String name : files) {
       try {
         dir.deleteFile(name);
       } catch (Throwable ignored) {
         // ignore
       }
     }
   }

   /**
    * Copy one file's contents to another file. The target will be overwritten
    * if it exists. The source must exist.
    */
   public static void copy(File source, File target) throws IOException {
     FileInputStream fis = null;
     FileOutputStream fos = null;
     try {
       fis = new FileInputStream(source);
       fos = new FileOutputStream(target);

       final byte [] buffer = new byte [1024 * 8];
       int len;
       while ((len = fis.read(buffer)) > 0) {
         fos.write(buffer, 0, len);
       }
     } finally {
       close(fis, fos);
     }
   }

   /**
    * Simple utilty method that takes a previously caught
    * {@code Throwable} and rethrows either {@code
    * IOException} or an unchecked exception.  If the
    * argument is null then this method does nothing.
    */
   public static void reThrow(Throwable th) throws IOException {
     if (th != null) {
       if (th instanceof IOException) {
         throw (IOException) th;
       }
       if (th instanceof RuntimeException) {
         throw (RuntimeException) th;
       }
       if (th instanceof Error) {
         throw (Error) th;
       }
       throw new RuntimeException(th);
     }
   }
 }
	package org.apache.lucene.util;

	/*
	* 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.BufferedReader;
	import java.io.Closeable;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.Reader;
	import java.nio.charset.Charset;
	import java.nio.charset.CharsetDecoder;
	import java.nio.charset.CodingErrorAction;

	import org.apache.lucene.store.Directory;

	/** This class emulates the new Java 7 "Try-With-Resources" statement.
	* Remove once Lucene is on Java 7.
	* @lucene.internal */
	public final class IOUtils {

	/**
	* UTF-8 charset string
	* @see Charset#forName(String)
	*/
	public static final String UTF_8 = "UTF-8";

	/**
	* UTF-8 {@link Charset} instance to prevent repeated
	* {@link Charset#forName(String)} lookups
	*/
	public static final Charset CHARSET_UTF_8 = Charset.forName("UTF-8");
	private IOUtils() {} // no instance

	/**
	* <p>Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions. Some of the <tt>Closeable</tt>s
	* may be null, they are ignored. After everything is closed, method either throws <tt>priorException</tt>,
	* if one is supplied, or the first of suppressed exceptions, or completes normally.</p>
	* <p>Sample usage:<br/>
	* <pre class="prettyprint">
	* Closeable resource1 = null, resource2 = null, resource3 = null;
	* ExpectedException priorE = null;
	* try {
	* resource1 = ...; resource2 = ...; resource3 = ...; // Acquisition may throw ExpectedException
	* ..do..stuff.. // May throw ExpectedException
	* } catch (ExpectedException e) {
	* priorE = e;
	* } finally {
	* closeWhileHandlingException(priorE, resource1, resource2, resource3);
	* }
	* </pre>
	* </p>
	* @param priorException <tt>null</tt> or an exception that will be rethrown after method completion
	* @param objects objects to call <tt>close()</tt> on
	*/
	public static <E extends Exception> void closeWhileHandlingException(E priorException, Closeable... objects) throws E, IOException {
	Throwable th = null;

	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	addSuppressed((priorException == null) ? th : priorException, t);
	if (th == null) {
	th = t;
	}
	}
	}

	if (priorException != null) {
	throw priorException;
	} else {
	reThrow(th);
	}
	}

	/**
	* Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
	* @see #closeWhileHandlingException(Exception, Closeable...) */
	public static <E extends Exception> void closeWhileHandlingException(E priorException, Iterable<? extends Closeable> objects) throws E, IOException {
	Throwable th = null;

	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	addSuppressed((priorException == null) ? th : priorException, t);
	if (th == null) {
	th = t;
	}
	}
	}

	if (priorException != null) {
	throw priorException;
	} else {
	reThrow(th);
	}
	}

	/**
	* Closes all given <tt>Closeable</tt>s. Some of the
	* <tt>Closeable</tt>s may be null; they are
	* ignored. After everything is closed, the method either
	* throws the first exception it hit while closing, or
	* completes normally if there were no exceptions.
	*
	* @param objects
	* objects to call <tt>close()</tt> on
	*/
	public static void close(Closeable... objects) throws IOException {
	Throwable th = null;

	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	addSuppressed(th, t);
	if (th == null) {
	th = t;
	}
	}
	}

	reThrow(th);
	}

	/**
	* Closes all given <tt>Closeable</tt>s.
	* @see #close(Closeable...)
	*/
	public static void close(Iterable<? extends Closeable> objects) throws IOException {
	Throwable th = null;

	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	addSuppressed(th, t);
	if (th == null) {
	th = t;
	}
	}
	}

	reThrow(th);
	}

	/**
	* Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
	* Some of the <tt>Closeable</tt>s may be null, they are ignored.
	*
	* @param objects
	* objects to call <tt>close()</tt> on
	*/
	public static void closeWhileHandlingException(Closeable... objects) {
	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	}
	}
	}

	/**
	* Closes all given <tt>Closeable</tt>s, suppressing all thrown exceptions.
	* @see #closeWhileHandlingException(Closeable...)
	*/
	public static void closeWhileHandlingException(Iterable<? extends Closeable> objects) {
	for (Closeable object : objects) {
	try {
	if (object != null) {
	object.close();
	}
	} catch (Throwable t) {
	}
	}
	}

	/** adds a Throwable to the list of suppressed Exceptions of the first Throwable
	* @param exception this exception should get the suppressed one added
	* @param suppressed the suppressed exception
	*/
	private static void addSuppressed(Throwable exception, Throwable suppressed) {
	if (exception != null && suppressed != null) {
	exception.addSuppressed(suppressed);
	}
	}

	/**
	* Wrapping the given {@link InputStream} in a reader using a {@link CharsetDecoder}.
	* Unlike Java's defaults this reader will throw an exception if your it detects
	* the read charset doesn't match the expected {@link Charset}.
	* <p>
	* Decoding readers are useful to load configuration files, stopword lists or synonym files
	* to detect character set problems. However, its not recommended to use as a common purpose
	* reader.
	*
	* @param stream the stream to wrap in a reader
	* @param charSet the expected charset
	* @return a wrapping reader
	*/
	public static Reader getDecodingReader(InputStream stream, Charset charSet) {
	final CharsetDecoder charSetDecoder = charSet.newDecoder()
	.onMalformedInput(CodingErrorAction.REPORT)
	.onUnmappableCharacter(CodingErrorAction.REPORT);
	return new BufferedReader(new InputStreamReader(stream, charSetDecoder));
	}

	/**
	* Opens a Reader for the given {@link File} using a {@link CharsetDecoder}.
	* Unlike Java's defaults this reader will throw an exception if your it detects
	* the read charset doesn't match the expected {@link Charset}.
	* <p>
	* Decoding readers are useful to load configuration files, stopword lists or synonym files
	* to detect character set problems. However, its not recommended to use as a common purpose
	* reader.
	* @param file the file to open a reader on
	* @param charSet the expected charset
	* @return a reader to read the given file
	*/
	public static Reader getDecodingReader(File file, Charset charSet) throws IOException {
	FileInputStream stream = null;
	boolean success = false;
	try {
	stream = new FileInputStream(file);
	final Reader reader = getDecodingReader(stream, charSet);
	success = true;
	return reader;

	} finally {
	if (!success) {
	IOUtils.close(stream);
	}
	}
	}

	/**
	* Opens a Reader for the given resource using a {@link CharsetDecoder}.
	* Unlike Java's defaults this reader will throw an exception if your it detects
	* the read charset doesn't match the expected {@link Charset}.
	* <p>
	* Decoding readers are useful to load configuration files, stopword lists or synonym files
	* to detect character set problems. However, its not recommended to use as a common purpose
	* reader.
	* @param clazz the class used to locate the resource
	* @param resource the resource name to load
	* @param charSet the expected charset
	* @return a reader to read the given file
	*
	*/
	public static Reader getDecodingReader(Class<?> clazz, String resource, Charset charSet) throws IOException {
	InputStream stream = null;
	boolean success = false;
	try {
	stream = clazz
	.getResourceAsStream(resource);
	final Reader reader = getDecodingReader(stream, charSet);
	success = true;
	return reader;
	} finally {
	if (!success) {
	IOUtils.close(stream);
	}
	}
	}

	/**
	* Deletes all given files, suppressing all thrown IOExceptions.
	* <p>
	* Note that the files should not be null.
	*/
	public static void deleteFilesIgnoringExceptions(Directory dir, String... files) {
	for (String name : files) {
	try {
	dir.deleteFile(name);
	} catch (Throwable ignored) {
	// ignore
	}
	}
	}

	/**
	* Copy one file's contents to another file. The target will be overwritten
	* if it exists. The source must exist.
	*/
	public static void copy(File source, File target) throws IOException {
	FileInputStream fis = null;
	FileOutputStream fos = null;
	try {
	fis = new FileInputStream(source);
	fos = new FileOutputStream(target);

	final byte [] buffer = new byte [1024 * 8];
	int len;
	while ((len = fis.read(buffer)) > 0) {
	fos.write(buffer, 0, len);
	}
	} finally {
	close(fis, fos);
	}
	}

	/**
	* Simple utilty method that takes a previously caught
	* {@code Throwable} and rethrows either {@code
	* IOException} or an unchecked exception. If the
	* argument is null then this method does nothing.
	*/
	public static void reThrow(Throwable th) throws IOException {
	if (th != null) {
	if (th instanceof IOException) {
	throw (IOException) th;
	}
	if (th instanceof RuntimeException) {
	throw (RuntimeException) th;
	}
	if (th instanceof Error) {
	throw (Error) th;
	}
	throw new RuntimeException(th);
	}
	}
	}