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/*
*
* 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.
*
*/
package org.apache.qpid.util;
import java.io.*;
/**
* FileUtils provides some simple helper methods for working with files. It follows the convention of wrapping all
* checked exceptions as runtimes, so code using these methods is free of try-catch blocks but does not expect to
* recover from errors.
*
* <p/><table id="crc"><caption>CRC Card</caption>
* <tr><th> Responsibilities <th> Collaborations
* <tr><td> Read a text file as a string.
* <tr><td> Open a file or default resource as an input stream.
* </table>
*/
public class FileUtils
{
/**
* Reads a text file as a string.
*
* @param filename The name of the file.
*
* @return The contents of the file.
*/
public static String readFileAsString(String filename)
{
BufferedInputStream is = null;
try
{
is = new BufferedInputStream(new FileInputStream(filename));
}
catch (FileNotFoundException e)
{
throw new RuntimeException(e);
}
return readStreamAsString(is);
}
/**
* Reads a text file as a string.
*
* @param file The file.
*
* @return The contents of the file.
*/
public static String readFileAsString(File file)
{
BufferedInputStream is = null;
try
{
is = new BufferedInputStream(new FileInputStream(file));
}
catch (FileNotFoundException e)
{
throw new RuntimeException(e);
}
return readStreamAsString(is);
}
/**
* Reads the contents of a reader, one line at a time until the end of stream is encountered, and returns all
* together as a string.
*
* @param is The reader.
*
* @return The contents of the reader.
*/
private static String readStreamAsString(BufferedInputStream is)
{
try
{
byte[] data = new byte[4096];
StringBuffer inBuffer = new StringBuffer();
String line;
int read;
while ((read = is.read(data)) != -1)
{
String s = new String(data, 0, read);
inBuffer.append(s);
}
return inBuffer.toString();
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
/**
* Either opens the specified filename as an input stream, or uses the default resource loaded using the
* specified class loader, if opening the file fails or no file name is specified.
*
* @param filename The name of the file to open.
* @param defaultResource The name of the default resource on the classpath if the file cannot be opened.
* @param cl The classloader to load the default resource with.
*
* @return An input stream for the file or resource, or null if one could not be opened.
*/
public static InputStream openFileOrDefaultResource(String filename, String defaultResource, ClassLoader cl)
{
InputStream is = null;
// Flag to indicate whether the default resource should be used. By default this is true, so that the default
// is used when opening the file fails.
boolean useDefault = true;
// Try to open the file if one was specified.
if (filename != null)
{
try
{
is = new BufferedInputStream(new FileInputStream(new File(filename)));
// Clear the default flag because the file was succesfully opened.
useDefault = false;
}
catch (FileNotFoundException e)
{
// Ignore this exception, the default will be used instead.
}
}
// Load the default resource if a file was not specified, or if opening the file failed.
if (useDefault)
{
is = cl.getResourceAsStream(defaultResource);
}
return is;
}
/**
* Copies the specified source file to the specified destintaion file. If the destinationst file does not exist,
* it is created.
*
* @param src The source file name.
* @param dst The destination file name.
*/
public static void copy(File src, File dst)
{
try
{
InputStream in = new FileInputStream(src);
if (!dst.exists())
{
dst.createNewFile();
}
OutputStream out = new FileOutputStream(dst);
// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0)
{
out.write(buf, 0, len);
}
in.close();
out.close();
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
/*
* Deletes a given file
*/
public static void deleteFile(String filePath) throws IOException
{
delete(new File(filePath), false);
}
/**
* Delete a given file, if a directory is specified and recursive set then delete the whole tree
* @param filePath the File object to start at
* @param recursive boolean to recurse if a directory is specified.
* @throws IOException
*/
public static void delete(File filePath, boolean recursive) throws IOException
{
if (filePath.isDirectory())
{
if (recursive)
{
for (File subFile : filePath.listFiles())
{
delete(subFile, true);
}
}
}
filePath.delete();
}
}
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