com.izforge.izpack.installer.unpacker.AbstractPackResources Maven / Gradle / Ivy
/*
* IzPack - Copyright 2001-2012 Julien Ponge, All Rights Reserved.
*
* http://izpack.org/
* http://izpack.codehaus.org/
*
* Copyright 2012 Tim Anderson
*
* Licensed 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 com.izforge.izpack.installer.unpacker;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import com.izforge.izpack.api.data.InstallData;
import com.izforge.izpack.api.exception.ResourceException;
import com.izforge.izpack.api.exception.ResourceInterruptedException;
import com.izforge.izpack.api.exception.ResourceNotFoundException;
import com.izforge.izpack.api.resource.Resources;
/**
* Abstract implementation of the {@link PackResources} interface.
*
* @author Tim Anderson
*/
public abstract class AbstractPackResources implements PackResources
{
/**
* The resources.
*/
private final Resources resources;
/**
* The installation data.
*/
private final InstallData installData;
/**
* Constructs an {@code AbstractPackResources}.
*
* @param resources the resources
* @param installData the installation data
*/
public AbstractPackResources(Resources resources, InstallData installData)
{
this.installData = installData;
this.resources = resources;
}
/**
* Returns the stream to a resource.
*
* @param name the resource name
* @return a stream to the resource
* @throws ResourceNotFoundException if the resource cannot be found
* @throws ResourceInterruptedException if resource retrieval is interrupted
* @throws ResourceException for any other resource error
*/
@Override
public InputStream getPackStream(String name)
{
InputStream result;
String webDirURL = installData.getInfo().getWebDirURL();
if (webDirURL == null)
{
result = getLocalPackStream(name);
}
else
{
result = getWebPackStream(name, webDirURL);
}
String className = installData.getInfo().getPackDecoderClassName();
if (className != null)
{
result = getDecodingInputStream(result, className);
}
return result;
}
/**
* Returns the stream to a resource.
*
* @param name the resource name
* @return a stream to the resource
* @throws ResourceNotFoundException if the resource cannot be found
* @throws ResourceException for any other resource error
*/
@Override
public InputStream getInputStream(String name)
{
// TODO - this is invoked to get multi-volume info, so should check on web dir.
return resources.getInputStream(name);
}
/**
* Returns a stream that decodes the supplied stream.
*
* @param in the stream to decode
* @param className the decoding input stream class name.
* @return the decoding stream
* @throws ResourceException for any error
*/
protected InputStream getDecodingInputStream(InputStream in, String className)
{
Object result;
try
{
Class decoder = Class.forName(className);
Class[] paramsClasses = {java.io.InputStream.class};
Constructor constructor = decoder.getDeclaredConstructor(paramsClasses);
// Our first used decoder input stream (bzip2) reads byte for byte from
// the source. Therefore we put a buffering stream between it and the source.
InputStream buffer = new BufferedInputStream(in);
Object[] params = {buffer};
result = constructor.newInstance(params);
}
catch (Exception exception)
{
throw new ResourceException("Failed to create stream to decode resource", exception);
}
if (!InputStream.class.isInstance(result))
{
throw new ResourceException("Cannot decode resource: '" + className + "' must be derived from "
+ InputStream.class.getName());
}
return (InputStream) result;
}
/**
* Returns a stream to a local pack.
*
* @param name the pack name
* @return the pack stream
*/
protected InputStream getLocalPackStream(String name)
{
return resources.getInputStream("packs/pack-" + name);
}
/**
* Returns the stream to a web-based pack resource.
*
* @param name the resource name
* @param webDirURL the web URL to load the resource from
* @return a stream to the resource
* @throws ResourceNotFoundException if the resource cannot be found
* @throws ResourceInterruptedException if resource retrieval is interrupted
*/
protected abstract InputStream getWebPackStream(String name, String webDirURL);
/**
* Returns the installation data.
*
* @return the installation data
*/
protected InstallData getInstallData()
{
return installData;
}
}