// Copyright (C) 2009 The Android Open Source Project
//
// 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 com.google.gerrit.sshd;
import com.google.common.collect.Maps;
import com.google.gerrit.extensions.registration.RegistrationHandle;
import com.google.inject.Binding;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import org.apache.sshd.server.Command;
import java.lang.annotation.Annotation;
import java.util.List;
import java.util.concurrent.ConcurrentMap;
/**
* Creates DispatchCommand using commands registered by {@link CommandModule}.
*/
public class DispatchCommandProvider implements Provider<DispatchCommand> {
@Inject
private Injector injector;
@Inject
private DispatchCommand.Factory factory;
private final CommandName parent;
private volatile ConcurrentMap<String, Provider<Command>> map;
public DispatchCommandProvider(final CommandName cn) {
this.parent = cn;
}
@Override
public DispatchCommand get() {
return factory.create(getMap());
}
public RegistrationHandle register(final CommandName name,
final Provider<Command> cmd) {
final ConcurrentMap<String, Provider<Command>> m = getMap();
if (m.putIfAbsent(name.value(), cmd) != null) {
throw new IllegalArgumentException(name.value() + " exists");
}
return new RegistrationHandle() {
@Override
public void remove() {
m.remove(name.value(), cmd);
}
};
}
public RegistrationHandle replace(final CommandName name,
final Provider<Command> cmd) {
final ConcurrentMap<String, Provider<Command>> m = getMap();
m.put(name.value(), cmd);
return new RegistrationHandle() {
@Override
public void remove() {
m.remove(name.value(), cmd);
}
};
}
ConcurrentMap<String, Provider<Command>> getMap() {
if (map == null) {
synchronized (this) {
if (map == null) {
map = createMap();
}
}
}
return map;
}
@SuppressWarnings("unchecked")
private ConcurrentMap<String, Provider<Command>> createMap() {
ConcurrentMap<String, Provider<Command>> m = Maps.newConcurrentMap();
for (final Binding<?> b : allCommands()) {
final Annotation annotation = b.getKey().getAnnotation();
if (annotation instanceof CommandName) {
final CommandName n = (CommandName) annotation;
if (!Commands.CMD_ROOT.equals(n) && Commands.isChild(parent, n)) {
m.put(n.value(), (Provider<Command>) b.getProvider());
}
}
}
return m;
}
private static final TypeLiteral<Command> type =
new TypeLiteral<Command>() {};
private List<Binding<Command>> allCommands() {
return injector.findBindingsByType(type);
}
}