/*
* Copyright 1999-2011 Alibaba Group.
*
* 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.alibaba.dubbo.rpc.cluster.support;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.extension.ExtensionLoader;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.ConfigUtils;
import com.alibaba.dubbo.common.utils.NamedThreadFactory;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Result;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.RpcInvocation;
import com.alibaba.dubbo.rpc.RpcResult;
import com.alibaba.dubbo.rpc.cluster.Directory;
import com.alibaba.dubbo.rpc.cluster.Merger;
import com.alibaba.dubbo.rpc.cluster.merger.MergerFactory;
/**
* @author <a href="mailto:gang.lvg@alibaba-inc.com">kimi</a>
*/
@SuppressWarnings( "unchecked" )
public class MergeableClusterInvoker<T> implements Invoker<T> {
private static final Logger log = LoggerFactory.getLogger(MergeableClusterInvoker.class);
private ExecutorService executor = Executors.newCachedThreadPool(new NamedThreadFactory("mergeable-cluster-executor", true));
private final Directory<T> directory;
public MergeableClusterInvoker(Directory<T> directory) {
this.directory = directory;
}
@SuppressWarnings("rawtypes")
public Result invoke(final Invocation invocation) throws RpcException {
List<Invoker<T>> invokers = directory.list(invocation);
String merger = getUrl().getMethodParameter( invocation.getMethodName(), Constants.MERGER_KEY );
if ( ConfigUtils.isEmpty(merger) ) { // 如果方法不需要Merge，退化为只调一个Group
for(final Invoker<T> invoker : invokers ) {
if (invoker.isAvailable()) {
return invoker.invoke(invocation);
}
}
return invokers.iterator().next().invoke(invocation);
}
Class<?> returnType;
try {
returnType = getInterface().getMethod(
invocation.getMethodName(), invocation.getParameterTypes() ).getReturnType();
} catch ( NoSuchMethodException e ) {
returnType = null;
}
Map<String, Future<Result>> results = new HashMap<String, Future<Result>>();
for( final Invoker<T> invoker : invokers ) {
Future<Result> future = executor.submit( new Callable<Result>() {
public Result call() throws Exception {
return invoker.invoke(new RpcInvocation(invocation, invoker));
}
} );
results.put( invoker.getUrl().getServiceKey(), future );
}
Object result = null;
List<Result> resultList = new ArrayList<Result>( results.size() );
int timeout = getUrl().getMethodParameter( invocation.getMethodName(), Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT );
for ( Map.Entry<String, Future<Result>> entry : results.entrySet() ) {
Future<Result> future = entry.getValue();
try {
Result r = future.get(timeout, TimeUnit.MILLISECONDS);
if (r.hasException()) {
log.error(new StringBuilder(32).append("Invoke ")
.append(getGroupDescFromServiceKey(entry.getKey()))
.append(" failed: ")
.append(r.getException().getMessage()).toString(),
r.getException());
} else {
resultList.add(r);
}
} catch ( Exception e ) {
throw new RpcException( new StringBuilder( 32 )
.append( "Failed to invoke service " )
.append( entry.getKey() )
.append( ": " )
.append( e.getMessage() ).toString(),
e );
}
}
if (resultList.size() == 0) {
return new RpcResult((Object)null);
} else if (resultList.size() == 1) {
return resultList.iterator().next();
}
if (returnType == void.class) {
return new RpcResult((Object)null);
}
if ( merger.startsWith(".") ) {
merger = merger.substring(1);
Method method;
try {
method = returnType.getMethod( merger, returnType );
} catch ( NoSuchMethodException e ) {
throw new RpcException( new StringBuilder( 32 )
.append( "Can not merge result because missing method [ " )
.append( merger )
.append( " ] in class [ " )
.append( returnType.getClass().getName() )
.append( " ]" )
.toString() );
}
if ( method != null ) {
if ( !Modifier.isPublic( method.getModifiers() ) ) {
method.setAccessible( true );
}
result = resultList.remove( 0 ).getValue();
try {
if ( method.getReturnType() != void.class
&& method.getReturnType().isAssignableFrom( result.getClass() ) ) {
for ( Result r : resultList ) {
result = method.invoke( result, r.getValue() );
}
} else {
for ( Result r : resultList ) {
method.invoke( result, r.getValue() );
}
}
} catch ( Exception e ) {
throw new RpcException(
new StringBuilder( 32 )
.append( "Can not merge result: " )
.append( e.getMessage() ).toString(),
e );
}
} else {
throw new RpcException(
new StringBuilder( 32 )
.append( "Can not merge result because missing method [ " )
.append( merger )
.append( " ] in class [ " )
.append( returnType.getClass().getName() )
.append( " ]" )
.toString() );
}
} else {
Merger resultMerger;
if (ConfigUtils.isDefault(merger)) {
resultMerger = MergerFactory.getMerger(returnType);
} else {
resultMerger = ExtensionLoader.getExtensionLoader(Merger.class).getExtension(merger);
}
if (resultMerger != null) {
List<Object> rets = new ArrayList<Object>(resultList.size());
for(Result r : resultList) {
rets.add(r.getValue());
}
result = resultMerger.merge(
rets.toArray((Object[])Array.newInstance(returnType, 0)));
} else {
throw new RpcException( "There is no merger to merge result." );
}
}
return new RpcResult( result );
}
public Class<T> getInterface() {
return directory.getInterface();
}
public URL getUrl() {
return directory.getUrl();
}
public boolean isAvailable() {
return directory.isAvailable();
}
public void destroy() {
directory.destroy();
}
private String getGroupDescFromServiceKey(String key) {
int index = key.indexOf("/");
if (index > 0) {
return new StringBuilder(32).append("group [ ")
.append(key.substring(0, index)).append(" ]").toString();
}
return key;
}
}