nextapp.echo.webcontainer.util.Resource Maven / Gradle / Ivy
/*
* This file is part of the Echo Web Application Framework (hereinafter "Echo").
* Copyright (C) 2002-2009 NextApp, Inc.
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*/
package nextapp.echo.webcontainer.util;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* Provides functionality for obtaining text and binary resource files.
*/
public class Resource {
/** Buffer size for use in streaming an InputStream to an OutputStream. */
private static final int BUFFER_SIZE = 4096;
/**
* A RuntimeException exception that will be thrown in the event that
* problems are encountered obtaining a resource.
*/
public static class ResourceException extends RuntimeException {
/** Serial Version UID. */
private static final long serialVersionUID = 20070101L;
/**
* Creates a resource exception.
*
* @param message a description of the error
* @param cause the causal exception
*/
private ResourceException(String message, Throwable cause) {
super(message, cause);
}
}
/**
* Retrieves the specified resource as a String.
*
* @param resourceName the name of the resource to be retrieved
* @return the specified resource as a String
*/
public static String getResourceAsString(String resourceName) {
return getResource(resourceName).toString();
}
/**
* Retrieves the specified resource as an array of bytes.
*
* @param resourceName the name of the resource to be retrieved
* @return the specified resource as an array of bytes
*/
public static byte[] getResourceAsByteArray(String resourceName) {
return getResource(resourceName).toByteArray();
}
/**
* An internal method used to retrieve a resource as a
* ByteArrayOutputStream.
*
* @param resourceName the name of the resource to be retrieved
* @return a ByteArrayOutputStream of the content of the
* resource
*/
private static ByteArrayOutputStream getResource(String resourceName) {
InputStream in = null;
byte[] buffer = new byte[BUFFER_SIZE];
ByteArrayOutputStream out = null;
int bytesRead = 0;
try {
in = Resource.class.getClassLoader().getResourceAsStream(resourceName);
if (in == null) {
throw new ResourceException("Resource does not exist: \"" + resourceName + "\".", null);
}
out = new ByteArrayOutputStream();
do {
bytesRead = in.read(buffer);
if (bytesRead > 0) {
out.write(buffer, 0, bytesRead);
}
} while (bytesRead > 0);
} catch (IOException ex) {
throw new ResourceException("Cannot get resource: \"" + resourceName + "\".", ex);
} finally {
if (in != null) { try { in.close(); } catch (IOException ex) { } }
}
return out;
}
/** Non-instantiable class. */
private Resource() { }
}