/*
 * Copyright 2002-2018 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.remoting.support;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;

import org.springframework.lang.Nullable;

Encapsulates a remote invocation result, holding a result value or an exception.
Used for HTTP-based serialization invokers.
This is an SPI class, typically not used directly by applications.
Can be subclassed for additional invocation parameters.
Both RemoteInvocation and RemoteInvocationResult are designed for use with standard Java serialization as well as JavaBean-style serialization. 
Author:
Juergen Hoeller
See Also:
RemoteInvocation
Since:
1.1/**
 * Encapsulates a remote invocation result, holding a result value or an exception.
 * Used for HTTP-based serialization invokers.
 *
 * <p>This is an SPI class, typically not used directly by applications.
 * Can be subclassed for additional invocation parameters.
 *
 * <p>Both {@link RemoteInvocation} and {@link RemoteInvocationResult} are designed
 * for use with standard Java serialization as well as JavaBean-style serialization.
 *
 * @author Juergen Hoeller
 * @since 1.1
 * @see RemoteInvocation
 */
public class RemoteInvocationResult implements Serializable {

	
Use serialVersionUID from Spring 1.1 for interoperability. /** Use serialVersionUID from Spring 1.1 for interoperability. */
	private static final long serialVersionUID = 2138555143707773549L;


	@Nullable
	private Object value;

	@Nullable
	private Throwable exception;


	
Create a new RemoteInvocationResult for the given result value.
Params:
value – the result value returned by a successful invocation
of the target method/**
	 * Create a new RemoteInvocationResult for the given result value.
	 * @param value the result value returned by a successful invocation
	 * of the target method
	 */
	public RemoteInvocationResult(@Nullable Object value) {
		this.value = value;
	}

	
Create a new RemoteInvocationResult for the given exception.
Params:
exception – the exception thrown by an unsuccessful invocation
of the target method/**
	 * Create a new RemoteInvocationResult for the given exception.
	 * @param exception the exception thrown by an unsuccessful invocation
	 * of the target method
	 */
	public RemoteInvocationResult(@Nullable Throwable exception) {
		this.exception = exception;
	}

	
Create a new RemoteInvocationResult for JavaBean-style deserialization
(e.g. with Jackson).
See Also:
setValue
setException/**
	 * Create a new RemoteInvocationResult for JavaBean-style deserialization
	 * (e.g. with Jackson).
	 * @see #setValue
	 * @see #setException
	 */
	public RemoteInvocationResult() {
	}


	
Set the result value returned by a successful invocation of the
target method, if any.
This setter is intended for JavaBean-style deserialization. Use RemoteInvocationResult(Object) otherwise. 
See Also:
RemoteInvocationResult()/**
	 * Set the result value returned by a successful invocation of the
	 * target method, if any.
	 * <p>This setter is intended for JavaBean-style deserialization.
	 * Use {@link #RemoteInvocationResult(Object)} otherwise.
	 * @see #RemoteInvocationResult()
	 */
	public void setValue(@Nullable Object value) {
		this.value = value;
	}

	
Return the result value returned by a successful invocation
of the target method, if any.
See Also:
hasException/**
	 * Return the result value returned by a successful invocation
	 * of the target method, if any.
	 * @see #hasException
	 */
	@Nullable
	public Object getValue() {
		return this.value;
	}

	
Set the exception thrown by an unsuccessful invocation of the
target method, if any.
This setter is intended for JavaBean-style deserialization. Use RemoteInvocationResult(Throwable) otherwise. 
See Also:
RemoteInvocationResult()/**
	 * Set the exception thrown by an unsuccessful invocation of the
	 * target method, if any.
	 * <p>This setter is intended for JavaBean-style deserialization.
	 * Use {@link #RemoteInvocationResult(Throwable)} otherwise.
	 * @see #RemoteInvocationResult()
	 */
	public void setException(@Nullable Throwable exception) {
		this.exception = exception;
	}

	
Return the exception thrown by an unsuccessful invocation
of the target method, if any.
See Also:
hasException/**
	 * Return the exception thrown by an unsuccessful invocation
	 * of the target method, if any.
	 * @see #hasException
	 */
	@Nullable
	public Throwable getException() {
		return this.exception;
	}

	
Return whether this invocation result holds an exception. If this returns false, the result value applies (even if it is null). 
See Also:
getValue
getException/**
	 * Return whether this invocation result holds an exception.
	 * If this returns {@code false}, the result value applies
	 * (even if it is {@code null}).
	 * @see #getValue
	 * @see #getException
	 */
	public boolean hasException() {
		return (this.exception != null);
	}

	
Return whether this invocation result holds an InvocationTargetException,
thrown by an invocation of the target method itself.
See Also:
hasException()/**
	 * Return whether this invocation result holds an InvocationTargetException,
	 * thrown by an invocation of the target method itself.
	 * @see #hasException()
	 */
	public boolean hasInvocationTargetException() {
		return (this.exception instanceof InvocationTargetException);
	}


	
Recreate the invocation result, either returning the result value
in case of a successful invocation of the target method, or
rethrowing the exception thrown by the target method.
Throws:
Throwable – the exception, if any
Returns:
the result value, if any/**
	 * Recreate the invocation result, either returning the result value
	 * in case of a successful invocation of the target method, or
	 * rethrowing the exception thrown by the target method.
	 * @return the result value, if any
	 * @throws Throwable the exception, if any
	 */
	@Nullable
	public Object recreate() throws Throwable {
		if (this.exception != null) {
			Throwable exToThrow = this.exception;
			if (this.exception instanceof InvocationTargetException) {
				exToThrow = ((InvocationTargetException) this.exception).getTargetException();
			}
			RemoteInvocationUtils.fillInClientStackTraceIfPossible(exToThrow);
			throw exToThrow;
		}
		else {
			return this.value;
		}
	}

}