donaldp 2002/10/06 22:25:54
Added: loader/src/java/org/apache/excalibur/loader/builder
LoaderBuilder.java LoaderResolver.java
Log:
Add in the start of the ClassLoader building code
Revision Changes Path
1.1
jakarta-avalon-excalibur/loader/src/java/org/apache/excalibur/loader/builder/LoaderBuilder.java
Index: LoaderBuilder.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
package org.apache.excalibur.loader.builder;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import org.apache.avalon.excalibur.extension.Extension;
import org.apache.excalibur.loader.metadata.ClassLoaderMetaData;
import org.apache.excalibur.loader.metadata.ClassLoaderSetMetaData;
import org.apache.excalibur.loader.metadata.FileSetMetaData;
import org.apache.excalibur.loader.metadata.JoinMetaData;
/**
* This class is responsible for building the set of
* actual {@link java.lang.ClassLoader}s out of the
* {@link ClassLoaderSetMetaData} objects.
*
* @author <a href="mailto:peter at apache.org">Peter Donald</a>
* @version $Revision: 1.1 $ $Date: 2002/10/07 05:25:54 $
*/
public class LoaderBuilder
{
public Map buildClassLoaders( final ClassLoaderSetMetaData set,
final LoaderResolver policy,
final Map predefined )
throws Exception
{
final HashMap classLoaders = new HashMap();
addPredefined( set.getPredefined(), predefined, classLoaders );
addAllClassLoaders( set, policy, classLoaders );
return classLoaders;
}
private void addAllClassLoaders( final ClassLoaderSetMetaData set,
final LoaderResolver policy,
final Map classLoaders )
throws Exception
{
final ClassLoaderMetaData[] classLoaderDefs = set.getClassLoaders();
for( int i = 0; i < classLoaderDefs.length; i++ )
{
final String name = classLoaderDefs[ i ].getName();
processClassLoader( name, set, policy, classLoaders );
final ClassLoader classLoader =
buildRegularClassLoader( classLoaderDefs[ i ], policy, classLoaders
);
classLoaders.put( name, classLoader );
}
}
private void processClassLoader( final String name,
final ClassLoaderSetMetaData set,
final LoaderResolver policy,
final Map classLoaders )
throws Exception
{
if( classLoaders.containsKey( name ) )
{
return;
}
final ClassLoaderMetaData regular = set.getClassLoader( name );
if( null != regular )
{
//Make sure parent classloader is built
processClassLoader( regular.getParent(),
set,
policy,
classLoaders );
final ClassLoader classLoader =
buildRegularClassLoader( regular, policy, classLoaders );
classLoaders.put( name, classLoader );
}
else
{
final JoinMetaData join = set.getJoin( name );
//Make sure all our dependencies are processed
final String[] names = join.getClassloaders();
for( int i = 0; i < names.length; i++ )
{
processClassLoader( names[ i ], set, policy, classLoaders );
}
final ClassLoader classLoader =
buildJoinClassLoader( join, policy, classLoaders );
classLoaders.put( name, classLoader );
}
}
/**
* Create a Join ClassLoader.
*
* @param join the metadata
* @param policy the policy to use to resolve URLs etc
* @param classLoaders the already created ClassLoaders
* @return the created JoinClassLoader
*/
private ClassLoader buildJoinClassLoader( final JoinMetaData join,
final LoaderResolver policy,
final Map classLoaders )
throws Exception
{
final ArrayList list = new ArrayList();
final String[] names = join.getClassloaders();
for( int i = 0; i < names.length; i++ )
{
list.add( classLoaders.get( names[ i ] ) );
}
final ClassLoader[] elements =
(ClassLoader[])list.toArray( new ClassLoader[ list.size() ] );
return policy.createJoinClassLoader( elements );
}
/**
* Build a regular classloader with entries, extensions
* and filesets fully resolved.
*
* @param metaData the classloader definition
* @param policy the policy to use when creating URLs/Extensions etc
* @param classLoaders the already created ClassLoaders
* @return the created ClassLoader
* @throws Exception if unable to create ClassLoader
*/
private ClassLoader buildRegularClassLoader( final ClassLoaderMetaData metaData,
final LoaderResolver policy,
final Map classLoaders )
throws Exception
{
final ClassLoader parent =
getParentClassLoader( metaData.getName(),
metaData.getParent(),
classLoaders );
final ArrayList urlSet = new ArrayList();
final String[] entrys = metaData.getEntrys();
for( int i = 0; i < entrys.length; i++ )
{
final URL url = policy.resolveURL( entrys[ i ] );
urlSet.add( url );
}
//Add all filesets defined for classloader
final FileSetMetaData[] filesets = metaData.getFilesets();
for( int i = 0; i < filesets.length; i++ )
{
final FileSetMetaData fileset = filesets[ i ];
final String baseDirectory = fileset.getBaseDirectory();
final String[] includes = fileset.getIncludes();
final String[] excludes = fileset.getExcludes();
final URL[] urls =
policy.resolveFileSet( baseDirectory,
includes,
excludes );
for( int j = 0; j < urls.length; j++ )
{
urlSet.add( urls[ j ] );
}
}
final Extension[] extensions = metaData.getExtensions();
for( int i = 0; i < extensions.length; i++ )
{
final URL url = policy.resolveExtension( extensions[ i ] );
urlSet.add( url );
}
final URL[] urls = (URL[])urlSet.toArray( new URL[ urlSet.size() ] );
return policy.createClassLoader( parent, urls );
}
/**
* Return the parent classloader for a particular classloader.
*
* @param name the name of classloader that has the parent
* @param parentName the parent classloaders name
* @param classLoaders the set of defined classloaders
* @return the parent classloader (if any)
*/
private ClassLoader getParentClassLoader( final String name,
final String parentName,
final Map classLoaders )
{
final ClassLoader parent =
(ClassLoader)classLoaders.get( parentName );
if( null == parent )
{
final String message =
"Missing " + name + "'s parent ClassLoader " + parentName;
throw new IllegalArgumentException( message );
}
return parent;
}
/**
* Add all the predefined classloaders to the set of available
* ClassLoaders.
*
* @param entrys the names of predefined classloaders
* @param predefined the map containg predefined classloaders
* @param classLoaders the destination map of classloaders
*/
private void addPredefined( final String[] entrys,
final Map predefined,
final HashMap classLoaders )
{
for( int i = 0; i < entrys.length; i++ )
{
final String name = entrys[ i ];
final ClassLoader classLoader =
(ClassLoader)predefined.get( name );
if( null == classLoader )
{
final String message =
"Missing predefined ClassLoader " + name;
throw new IllegalArgumentException( message );
}
classLoaders.put( name, classLoader );
}
}
}
1.1
jakarta-avalon-excalibur/loader/src/java/org/apache/excalibur/loader/builder/LoaderResolver.java
Index: LoaderResolver.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
package org.apache.excalibur.loader.builder;
import java.net.URL;
import org.apache.avalon.excalibur.extension.Extension;
/**
* This is the class that clients provide to implement
* a specific policy with respect to how ClassLoader
* hierarchy is constructed.
*
* @author <a href="mailto:peter at apache.org">Peter Donald</a>
* @version $Revision: 1.1 $ $Date: 2002/10/07 05:25:54 $
*/
public interface LoaderResolver
{
/**
* Resolve an Extension to a URL.
* The URL that locates the "Optional Package" that
* provides specified Extension.
*
* @param extension the extension
* @return the URL that locates the "Optional Package" that
* provides specified Extension.
* @throws Exception if unable to locate Extension
*/
URL resolveExtension( Extension extension )
throws Exception;
/**
* Resolve a string into a URL.
* This allows resolvers to anchor URLs using relative URL
* or by handling non-standard URL protocols
* (such as "sar:/SAR-INF/lib/cornerstone.jar").
*
* @param location the location to transform into a URL
* @return the URL
* @throws Exception if unable to resolve URL
*/
URL resolveURL( String location )
throws Exception;
/**
* Resolve a fileset to a set of URLs.
*
* @param baseDirectory the Base directory of fileset
* @return the set of URLs making up fileset
* @throws Exception if unable to resolve fileset
*/
URL[] resolveFileSet( String baseDirectory,
String[] includes,
String[] excludes )
throws Exception;
/**
* Create a Join ClassLoader for specified ClassLoaders.
*
* @param classLoaders the ClassLoaders to "join"
* @return the joined ClassLoader
* @throws Exception if unable to create classloader
*/
ClassLoader createJoinClassLoader( ClassLoader[] classLoaders )
throws Exception;
/**
* Create a ClassLoader with specified parent and
* containing specified URLs.
*
* @param parent the parent classloader
* @param urls the URLs that the ClassLoader should contain
* @return the newly created ClassLoader
* @throws Exception if unable to create classloader
*/
ClassLoader createClassLoader( ClassLoader parent, URL[] urls )
throws Exception;
}
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