/*
* Copyright 2000-2004 The Apache Software Foundation
*
* 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 org.apache.bcel.util;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.Map;
import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.JavaClass;
/**
* This repository is used in situations where a Class is created
* outside the realm of a ClassLoader. Classes are loaded from
* the file systems using the paths specified in the given
* class path. By default, this is the value returned by
* ClassPath.getClassPath().
* <br>
* It is designed to be used as a singleton, however it
* can also be used with custom classpaths.
*
/**
* Abstract definition of a class repository. Instances may be used
* to load classes from different sources and may be used in the
* Repository.setRepository method.
*
* @see org.apache.bcel.Repository
*
* @version $Id: SyntheticRepository.java 386056 2006-03-15 11:31:56Z tcurdt $
* @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
* @author David Dixon-Peugh
*/
public class SyntheticRepository implements Repository {
private static final String DEFAULT_PATH = ClassPath.getClassPath();
private static Map _instances = new HashMap(); // CLASSPATH X REPOSITORY
private ClassPath _path = null;
private Map _loadedClasses = new HashMap(); // CLASSNAME X JAVACLASS
private SyntheticRepository(ClassPath path) {
_path = path;
}
public static SyntheticRepository getInstance() {
return getInstance(ClassPath.SYSTEM_CLASS_PATH);
}
public static SyntheticRepository getInstance( ClassPath classPath ) {
SyntheticRepository rep = (SyntheticRepository) _instances.get(classPath);
if (rep == null) {
rep = new SyntheticRepository(classPath);
_instances.put(classPath, rep);
}
return rep;
}
/**
* Store a new JavaClass instance into this Repository.
*/
public void storeClass( JavaClass clazz ) {
_loadedClasses.put(clazz.getClassName(), new SoftReference(clazz));
clazz.setRepository(this);
}
/**
* Remove class from repository
*/
public void removeClass( JavaClass clazz ) {
_loadedClasses.remove(clazz.getClassName());
}
/**
* Find an already defined (cached) JavaClass object by name.
*/
public JavaClass findClass( String className ) {
SoftReference ref = (SoftReference) _loadedClasses.get(className);
if (ref == null) {
return null;
}
return (JavaClass) ref.get();
}
/**
* Find a JavaClass object by name.
* If it is already in this Repository, the Repository version
* is returned. Otherwise, the Repository's classpath is searched for
* the class (and it is added to the Repository if found).
*
* @param className the name of the class
* @return the JavaClass object
* @throws ClassNotFoundException if the class is not in the
* Repository, and could not be found on the classpath
*/
public JavaClass loadClass( String className ) throws ClassNotFoundException {
if (className == null || className.equals("")) {
throw new IllegalArgumentException("Invalid class name " + className);
}
className = className.replace('/', '.'); // Just in case, canonical form
JavaClass clazz = findClass(className);
if (clazz != null) {
return clazz;
}
try {
return loadClass(_path.getInputStream(className), className);
} catch (IOException e) {
throw new ClassNotFoundException("Exception while looking for class " + className
+ ": " + e.toString());
}
}
/**
* Find the JavaClass object for a runtime Class object.
* If a class with the same name is already in this Repository,
* the Repository version is returned. Otherwise, getResourceAsStream()
* is called on the Class object to find the class's representation.
* If the representation is found, it is added to the Repository.
*
* @see Class
* @param clazz the runtime Class object
* @return JavaClass object for given runtime class
* @throws ClassNotFoundException if the class is not in the
* Repository, and its representation could not be found
*/
public JavaClass loadClass( Class clazz ) throws ClassNotFoundException {
String className = clazz.getName();
JavaClass repositoryClass = findClass(className);
if (repositoryClass != null) {
return repositoryClass;
}
String name = className;
int i = name.lastIndexOf('.');
if (i > 0) {
name = name.substring(i + 1);
}
return loadClass(clazz.getResourceAsStream(name + ".class"), className);
}
private JavaClass loadClass( InputStream is, String className ) throws ClassNotFoundException {
try {
if (is != null) {
ClassParser parser = new ClassParser(is, className);
JavaClass clazz = parser.parse();
storeClass(clazz);
return clazz;
}
} catch (IOException e) {
throw new ClassNotFoundException("Exception while looking for class " + className
+ ": " + e.toString());
}
throw new ClassNotFoundException("SyntheticRepository could not load " + className);
}
/** ClassPath associated with the Repository.
*/
public ClassPath getClassPath() {
return _path;
}
/** Clear all entries from cache.
*/
public void clear() {
_loadedClasses.clear();
}
}