/*
* Copyright 2007-2008 the original author or authors.
*
* 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.impalaframework.module.holder.graph;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import org.impalaframework.classloader.ClassLoaderFactory;
import org.impalaframework.classloader.ClassRetriever;
import org.impalaframework.classloader.URLClassRetriever;
import org.impalaframework.classloader.graph.DelegateClassLoader;
import org.impalaframework.classloader.graph.DependencyManager;
import org.impalaframework.classloader.graph.GraphClassLoader;
import org.impalaframework.module.ModuleDefinition;
import org.impalaframework.resolver.ModuleLocationResolver;
import org.impalaframework.util.ResourceUtils;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
/**
* {@link ClassLoaderFactory} implementation which returns a class loader representing the module
* as per the second argument to {@link #newClassLoader(ClassLoader, Object)}. Returns
* {@link GraphClassLoader} instance, that is, a class loader instance designed specifically
* to be used when modules are arranged in a graph, rather than in a hierarchy.
*/
public class GraphClassLoaderFactory implements ClassLoaderFactory {
private ModuleLocationResolver moduleLocationResolver;
private GraphClassLoaderRegistry classLoaderRegistry;
private GraphModuleStateHolder moduleStateHolder;
private boolean parentClassLoaderFirst;
public void init() {
Assert.notNull(moduleLocationResolver, "moduleLocationResolver cannot be null");
Assert.notNull(classLoaderRegistry, "classLoaderRegistry cannot be null");
Assert.notNull(moduleStateHolder, "moduleStateHolder cannot be null");
}
public ClassLoader newClassLoader(ClassLoader parent, ModuleDefinition moduleDefinition) {
if (classLoaderRegistry.getApplicationClassLoader() == null) {
classLoaderRegistry.setApplicationClassLoader(parent);
}
Assert.notNull(moduleDefinition, "moduleDefinition cannot be null");
DependencyManager newDependencyManager = moduleStateHolder.getDependencyManager();
Assert.notNull(newDependencyManager, "new dependency manager not available. Cannot create graph based class loader");
return newClassLoader(newDependencyManager, moduleDefinition);
}
public GraphClassLoader newClassLoader(DependencyManager dependencyManager, ModuleDefinition moduleDefinition) {
String moduleName = moduleDefinition.getName();
GraphClassLoader classLoader = classLoaderRegistry.getClassLoader(moduleName);
if (classLoader != null) {
return classLoader;
}
ClassRetriever resourceLoader = newResourceLoader(moduleDefinition);
List<ModuleDefinition> dependencies = dependencyManager.getOrderedModuleDependencies(moduleDefinition.getName());
List<GraphClassLoader> classLoaders = new ArrayList<GraphClassLoader>();
for (ModuleDefinition dependency : dependencies) {
if (dependency.getName().equals(moduleDefinition.getName())) continue;
classLoaders.add(newClassLoader(dependencyManager, dependency));
}
ClassLoader parentClassLoader = classLoaderRegistry.getApplicationClassLoader();
ClassLoader classLoaderToUse = parentClassLoader != null ? parentClassLoader : GraphClassLoaderFactory.class.getClassLoader();
GraphClassLoader gcl = new GraphClassLoader(classLoaderToUse , new DelegateClassLoader(classLoaders), resourceLoader, moduleDefinition, parentClassLoaderFirst);
classLoaderRegistry.addClassLoader(moduleDefinition.getName(), gcl);
return gcl;
}
ClassRetriever newResourceLoader(ModuleDefinition moduleDefinition) {
final List<Resource> classLocations = moduleLocationResolver.getApplicationModuleClassLocations(moduleDefinition.getName());
final File[] files = ResourceUtils.getFiles(classLocations);
URLClassRetriever classLoader = new URLClassRetriever(files);
return classLoader;
}
public void setModuleStateHolder(GraphModuleStateHolder graphModuleStateHolder) {
this.moduleStateHolder = graphModuleStateHolder;
}
public void setClassLoaderRegistry(GraphClassLoaderRegistry classLoaderRegistry) {
this.classLoaderRegistry = classLoaderRegistry;
}
public void setModuleLocationResolver(ModuleLocationResolver moduleLocationResolver) {
this.moduleLocationResolver = moduleLocationResolver;
}
public void setParentClassLoaderFirst(boolean parentClassLoaderFirst) {
this.parentClassLoaderFirst = parentClassLoaderFirst;
}
}