org.jboss.modules.DelegatingModuleLoader Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source.
* Copyright 2017 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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.jboss.modules;
/**
* A module loader which searches its finders first, and then delegates to another loader if the module is not found.
*/
public class DelegatingModuleLoader extends ModuleLoader {
private final ModuleLoader delegate;
/**
* Construct a new instance.
*
* @param delegate the delegate module loader, or {@code null} to skip delegation
* @param finders the module finders (must not be {@code null})
*/
public DelegatingModuleLoader(final ModuleLoader delegate, final ModuleFinder[] finders) {
super(finders);
this.delegate = delegate;
}
/**
* Construct a new instance.
*
* @param delegate the delegate module loader, or {@code null} to skip delegation
* @param finder the single module finder (must not be {@code null})
*/
public DelegatingModuleLoader(final ModuleLoader delegate, final ModuleFinder finder) {
super(finder);
this.delegate = delegate;
}
/**
* Preload the named module.
*
* @param name the module name (must not be {@code null})
* @return the loaded module, or {@code null} if it is not found in this loader or the delegate
* @throws ModuleLoadException if the module was found but failed to be loaded
*/
protected Module preloadModule(final String name) throws ModuleLoadException {
Module module = loadModuleLocal(name);
if (module == null) {
final ModuleLoader delegate = this.delegate;
if (delegate != null) {
module = preloadModule(name, delegate);
}
}
return module;
}
}