hadoop ProxyCombiner 源码

  • 2022-10-20
  • 浏览 (344)

haddop ProxyCombiner 代码

文件路径:/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProxyCombiner.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.apache.hadoop.ipc;

import org.apache.hadoop.thirdparty.com.google.common.base.Joiner;
import java.io.Closeable;
import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.apache.hadoop.io.MultipleIOException;
import org.apache.hadoop.ipc.Client.ConnectionId;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * A utility class used to combine two protocol proxies.
 * See {@link #combine(Class, Object...)}.
 */
public final class ProxyCombiner {

  private static final Logger LOG =
      LoggerFactory.getLogger(ProxyCombiner.class);

  private ProxyCombiner() { }

  /**
   * Combine two or more proxies which together comprise a single proxy
   * interface. This can be used for a protocol interface which {@code extends}
   * multiple other protocol interfaces. The returned proxy will implement
   * all of the methods of the combined proxy interface, delegating calls
   * to which proxy implements that method. If multiple proxies implement the
   * same method, the first in the list will be used for delegation.
   * <p>
   * This will check that every method on the combined interface is
   * implemented by at least one of the supplied proxy objects.
   *
   * @param combinedProxyInterface The interface of the combined proxy.
   * @param proxies The proxies which should be used as delegates.
   * @param <T> The type of the proxy that will be returned.
   * @return The combined proxy.
   */
  @SuppressWarnings("unchecked")
  public static <T> T combine(Class<T> combinedProxyInterface,
      Object... proxies) {
    methodLoop:
    for (Method m : combinedProxyInterface.getMethods()) {
      for (Object proxy : proxies) {
        try {
          proxy.getClass().getMethod(m.getName(), m.getParameterTypes());
          continue methodLoop; // go to the next method
        } catch (NoSuchMethodException nsme) {
          // Continue to try the next proxy
        }
      }
      throw new IllegalStateException("The proxies specified for "
          + combinedProxyInterface + " do not cover method " + m);
    }

    InvocationHandler handler =
        new CombinedProxyInvocationHandler(combinedProxyInterface, proxies);
    return (T) Proxy.newProxyInstance(combinedProxyInterface.getClassLoader(),
        new Class[] {combinedProxyInterface}, handler);
  }

  private static final class CombinedProxyInvocationHandler
      implements RpcInvocationHandler {

    private final Class<?> proxyInterface;
    private final Object[] proxies;

    private CombinedProxyInvocationHandler(Class<?> proxyInterface,
        Object[] proxies) {
      this.proxyInterface = proxyInterface;
      this.proxies = proxies;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args)
        throws Throwable {
      Exception lastException = null;
      for (Object underlyingProxy : proxies) {
        try {
          return method.invoke(underlyingProxy, args);
        } catch (IllegalAccessException|IllegalArgumentException e) {
          lastException = e;
        } catch (InvocationTargetException ite) {
          throw ite.getCause();
        }
      }
      // This shouldn't happen since the method coverage was verified in build()
      LOG.error("BUG: Method {} was unable to be found on any of the "
          + "underlying proxies for {}", method, proxy.getClass());
      throw new IllegalArgumentException("Method " + method + " not supported",
          lastException);
    }

    /**
     * Since this is incapable of returning multiple connection IDs, simply
     * return the first one. In most cases, the connection ID should be the same
     * for all proxies.
     */
    @Override
    public ConnectionId getConnectionId() {
      return RPC.getConnectionIdForProxy(proxies[0]);
    }

    @Override
    public String toString() {
      return "CombinedProxy[" + proxyInterface.getSimpleName() + "]["
          + Joiner.on(",").join(proxies) + "]";
    }

    @Override
    public void close() throws IOException {
      MultipleIOException.Builder exceptionBuilder =
          new MultipleIOException.Builder();
      for (Object proxy : proxies) {
        if (proxy instanceof Closeable) {
          try {
            ((Closeable) proxy).close();
          } catch (IOException ioe) {
            exceptionBuilder.add(ioe);
          }
        }
      }
      if (!exceptionBuilder.isEmpty()) {
        throw exceptionBuilder.build();
      }
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop AlignmentContext 源码

hadoop AsyncCallLimitExceededException 源码

hadoop CallQueueManager 源码

hadoop CallerContext 源码

hadoop Client 源码

hadoop ClientCache 源码

hadoop ClientId 源码

hadoop CostProvider 源码

hadoop DecayRpcScheduler 源码

hadoop DecayRpcSchedulerMXBean 源码

0  赞