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/*
* 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
*
* 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.apache.dubbo.rpc;
import org.apache.dubbo.common.Experimental;
import java.io.Serializable;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.function.BiConsumer;
import java.util.function.Function;
/**
* (API, Prototype, NonThreadSafe)
*
* An RPC {@link Result}.
*
* Known implementations are:
* 1. {@link AsyncRpcResult}, it's a {@link CompletionStage} whose underlying value signifies the return value of an RPC call.
* 2. {@link AppResponse}, it inevitably inherits {@link CompletionStage} and {@link Future}, but you should never treat AppResponse as a type of Future,
* instead, it is a normal concrete type.
*
* @serial Don't change the class name and package name.
* @see org.apache.dubbo.rpc.Invoker#invoke(Invocation)
* @see AppResponse
*/
public interface Result extends Serializable {
/**
* Get invoke result.
*
* @return result. if no result return null.
*/
Object getValue();
void setValue(Object value);
/**
* Get exception.
*
* @return exception. if no exception return null.
*/
Throwable getException();
void setException(Throwable t);
/**
* Has exception.
*
* @return has exception.
*/
boolean hasException();
/**
* Recreate.
*
*
* if (hasException()) {
* throw getException();
* } else {
* return getValue();
* }
*
*
* @return result.
* @throws if has exception throw it.
*/
Object recreate() throws Throwable;
/**
* get attachments.
*
* @return attachments.
*/
Map getAttachments();
/**
* get attachments.
*
* @return attachments.
*/
@Experimental("Experiment api for supporting Object transmission")
Map getObjectAttachments();
/**
* Add the specified map to existing attachments in this instance.
*
* @param map
*/
void addAttachments(Map map);
/**
* Add the specified map to existing attachments in this instance.
*
* @param map
*/
@Experimental("Experiment api for supporting Object transmission")
void addObjectAttachments(Map map);
/**
* Replace the existing attachments with the specified param.
*
* @param map
*/
void setAttachments(Map map);
/**
* Replace the existing attachments with the specified param.
*
* @param map
*/
@Experimental("Experiment api for supporting Object transmission")
void setObjectAttachments(Map map);
/**
* get attachment by key.
*
* @return attachment value.
*/
String getAttachment(String key);
/**
* get attachment by key.
*
* @return attachment value.
*/
@Experimental("Experiment api for supporting Object transmission")
Object getObjectAttachment(String key);
/**
* get attachment by key with default value.
*
* @return attachment value.
*/
String getAttachment(String key, String defaultValue);
/**
* get attachment by key with default value.
*
* @return attachment value.
*/
@Experimental("Experiment api for supporting Object transmission")
Object getObjectAttachment(String key, Object defaultValue);
void setAttachment(String key, String value);
@Experimental("Experiment api for supporting Object transmission")
void setAttachment(String key, Object value);
@Experimental("Experiment api for supporting Object transmission")
void setObjectAttachment(String key, Object value);
/**
* Add a callback which can be triggered when the RPC call finishes.
*
* Just as the method name implies, this method will guarantee the callback being triggered under the same context as when the call was started,
* see implementation in {@link Result#whenCompleteWithContext(BiConsumer)}
*
* @param fn
* @return
*/
Result whenCompleteWithContext(BiConsumer fn);
CompletableFuture thenApply(Function fn);
Result get() throws InterruptedException, ExecutionException;
Result get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException;
}