/*
* Copyright 2013 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.springframework.xd.dirt.module;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.springframework.xd.module.ModuleDefinition;
import org.springframework.xd.module.ModuleType;
/**
* A {@link ModuleRegistry} that delegates to several ModuleRegistries, in order.
*
* @author Eric Bottard
* @author Glenn Renfro
* @author David Turanski
*/
public class DelegatingModuleRegistry implements WriteableModuleRegistry {
private final List<ModuleRegistry> delegates = new ArrayList<ModuleRegistry>();
public DelegatingModuleRegistry(ModuleRegistry... delegates) {
for (ModuleRegistry delegate : delegates) {
this.delegates.add(delegate);
}
}
@Override
public ModuleDefinition findDefinition(String name, ModuleType moduleType) {
for (ModuleRegistry delegate : delegates) {
ModuleDefinition result = delegate.findDefinition(name, moduleType);
if (result != null) {
return result;
}
}
return null;
}
@Override
public List<ModuleDefinition> findDefinitions(String name) {
Set<String> alreadySeen = new HashSet<String>();
List<ModuleDefinition> result = new ArrayList<ModuleDefinition>();
for (ModuleRegistry delegate : delegates) {
List<ModuleDefinition> sub = delegate.findDefinitions(name);
for (ModuleDefinition definition : sub) {
// First registry's module shadows subsequent
if (alreadySeen.add(makeKeyFor(definition))) {
result.add(definition);
}
}
}
return result;
}
public void addDelegate(ModuleRegistry delegate) {
delegates.add(delegate);
}
private String makeKeyFor(ModuleDefinition definition) {
return definition.getType() + "|" + definition.getName();
}
@Override
public List<ModuleDefinition> findDefinitions(ModuleType type) {
ArrayList<ModuleDefinition> definitions = new ArrayList<ModuleDefinition>();
Set<String> alreadySeen = new HashSet<String>();
for (ModuleRegistry delegate : delegates) {
for (ModuleDefinition def : delegate.findDefinitions(type)) {
if (alreadySeen.add(makeKeyFor(def))) {
definitions.add(def);
}
}
}
return definitions;
}
@Override
public List<ModuleDefinition> findDefinitions() {
ArrayList<ModuleDefinition> definitions = new ArrayList<ModuleDefinition>();
Set<String> alreadySeen = new HashSet<String>();
for (ModuleRegistry delegate : delegates) {
for (ModuleDefinition def : delegate.findDefinitions()) {
if (alreadySeen.add(makeKeyFor(def))) {
definitions.add(def);
}
}
}
return definitions;
}
@Override
public boolean delete(ModuleDefinition definition) {
for (ModuleRegistry delegate : delegates) {
if (delegate instanceof WriteableModuleRegistry) {
WriteableModuleRegistry writeableModuleRegistry = (WriteableModuleRegistry) delegate;
if (writeableModuleRegistry.delete(definition)) {
return true;
}
}
}
return false;
}
@Override
public boolean registerNew(ModuleDefinition definition) {
for (ModuleRegistry delegate : delegates) {
if (delegate instanceof WriteableModuleRegistry) {
WriteableModuleRegistry writeableModuleRegistry = (WriteableModuleRegistry) delegate;
if (writeableModuleRegistry.registerNew(definition)) {
return true;
}
}
}
return false;
}
}