Spring Framework example source code file (SimpleHttpInvokerServiceExporter.java)

This example Spring Framework source code file (SimpleHttpInvokerServiceExporter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

classnotfoundexception, content-type, inputstream, inputstream, io, ioexception, ioexception, objectoutputstream, outputstream, outputstream, remoteinvocation, remoteinvocationresult, remoteinvocationresult, remoteinvocationserializingexporter, simplehttpinvokerserviceexporter

The Spring Framework SimpleHttpInvokerServiceExporter.java source code

/*
 * Copyright 2002-2007 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.httpinvoker;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

import org.springframework.remoting.rmi.RemoteInvocationSerializingExporter;
import org.springframework.remoting.support.RemoteInvocation;
import org.springframework.remoting.support.RemoteInvocationResult;

/**
 * HTTP request handler that exports the specified service bean as
 * HTTP invoker service endpoint, accessible via an HTTP invoker proxy.
 * Designed for Sun's JRE 1.6 HTTP server, implementing the
 * {@link com.sun.net.httpserver.HttpHandler} interface.
 *
 * <p>Deserializes remote invocation objects and serializes remote invocation
 * result objects. Uses Java serialization just like RMI, but provides the
 * same ease of setup as Caucho's HTTP-based Hessian and Burlap protocols.
 *
 * <p>HTTP invoker is the recommended protocol for Java-to-Java remoting.
 * It is more powerful and more extensible than Hessian and Burlap, at the
 * expense of being tied to Java. Nevertheless, it is as easy to set up as
 * Hessian and Burlap, which is its main advantage compared to RMI.
 *
 * @author Juergen Hoeller
 * @since 2.5.1
 * @see org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor
 * @see org.springframework.remoting.httpinvoker.HttpInvokerProxyFactoryBean
 * @see org.springframework.remoting.caucho.SimpleHessianServiceExporter
 * @see org.springframework.remoting.caucho.SimpleBurlapServiceExporter
 */
public class SimpleHttpInvokerServiceExporter extends RemoteInvocationSerializingExporter
		implements HttpHandler {

	/**
	 * Reads a remote invocation from the request, executes it,
	 * and writes the remote invocation result to the response.
	 * @see #readRemoteInvocation(com.sun.net.httpserver.HttpExchange)
	 * @see #invokeAndCreateResult(org.springframework.remoting.support.RemoteInvocation, Object)
	 * @see #writeRemoteInvocationResult(com.sun.net.httpserver.HttpExchange, org.springframework.remoting.support.RemoteInvocationResult)
	 */
	public void handle(HttpExchange exchange) throws IOException {
		try {
			RemoteInvocation invocation = readRemoteInvocation(exchange);
			RemoteInvocationResult result = invokeAndCreateResult(invocation, getProxy());
			writeRemoteInvocationResult(exchange, result);
			exchange.close();
		}
		catch (ClassNotFoundException ex) {
			throw new IOException("Class not found during deserialization", ex);
		}
	}

	/**
	 * Read a RemoteInvocation from the given HTTP request.
	 * <p>Delegates to
	 * {@link #readRemoteInvocation(com.sun.net.httpserver.HttpExchange, java.io.InputStream)}
	 * with the
	 * {@link com.sun.net.httpserver.HttpExchange#getRequestBody()} request's input stream}.
	 * @param exchange current HTTP request/response
	 * @return the RemoteInvocation object
	 * @throws java.io.IOException in case of I/O failure
	 * @throws ClassNotFoundException if thrown by deserialization
	 */
	protected RemoteInvocation readRemoteInvocation(HttpExchange exchange)
			throws IOException, ClassNotFoundException {

		return readRemoteInvocation(exchange, exchange.getRequestBody());
	}

	/**
	 * Deserialize a RemoteInvocation object from the given InputStream.
	 * <p>Gives {@link #decorateInputStream} a chance to decorate the stream
	 * first (for example, for custom encryption or compression). Creates a
	 * {@link org.springframework.remoting.rmi.CodebaseAwareObjectInputStream}
	 * and calls {@link #doReadRemoteInvocation} to actually read the object.
	 * <p>Can be overridden for custom serialization of the invocation.
	 * @param exchange current HTTP request/response
	 * @param is the InputStream to read from
	 * @return the RemoteInvocation object
	 * @throws java.io.IOException in case of I/O failure
	 * @throws ClassNotFoundException if thrown during deserialization
	 */
	protected RemoteInvocation readRemoteInvocation(HttpExchange exchange, InputStream is)
			throws IOException, ClassNotFoundException {

		ObjectInputStream ois = createObjectInputStream(decorateInputStream(exchange, is));
		return doReadRemoteInvocation(ois);
	}

	/**
	 * Return the InputStream to use for reading remote invocations,
	 * potentially decorating the given original InputStream.
	 * <p>The default implementation returns the given stream as-is.
	 * Can be overridden, for example, for custom encryption or compression.
	 * @param exchange current HTTP request/response
	 * @param is the original InputStream
	 * @return the potentially decorated InputStream
	 * @throws java.io.IOException in case of I/O failure
	 */
	protected InputStream decorateInputStream(HttpExchange exchange, InputStream is) throws IOException {
		return is;
	}

	/**
	 * Write the given RemoteInvocationResult to the given HTTP response.
	 * @param exchange current HTTP request/response
	 * @param result the RemoteInvocationResult object
	 * @throws java.io.IOException in case of I/O failure
	 */
	protected void writeRemoteInvocationResult(HttpExchange exchange, RemoteInvocationResult result)
			throws IOException {

		exchange.getResponseHeaders().set("Content-Type", getContentType());
		exchange.sendResponseHeaders(200, 0);
		writeRemoteInvocationResult(exchange, result, exchange.getResponseBody());
	}

	/**
	 * Serialize the given RemoteInvocation to the given OutputStream.
	 * <p>The default implementation gives {@link #decorateOutputStream} a chance
	 * to decorate the stream first (for example, for custom encryption or compression).
	 * Creates an {@link java.io.ObjectOutputStream} for the final stream and calls
	 * {@link #doWriteRemoteInvocationResult} to actually write the object.
	 * <p>Can be overridden for custom serialization of the invocation.
	 * @param exchange current HTTP request/response
	 * @param result the RemoteInvocationResult object
	 * @param os the OutputStream to write to
	 * @throws java.io.IOException in case of I/O failure
	 * @see #decorateOutputStream
	 * @see #doWriteRemoteInvocationResult
	 */
	protected void writeRemoteInvocationResult(
			HttpExchange exchange, RemoteInvocationResult result, OutputStream os) throws IOException {

		ObjectOutputStream oos = createObjectOutputStream(decorateOutputStream(exchange, os));
		doWriteRemoteInvocationResult(result, oos);
		oos.flush();
	}

	/**
	 * Return the OutputStream to use for writing remote invocation results,
	 * potentially decorating the given original OutputStream.
	 * <p>The default implementation returns the given stream as-is.
	 * Can be overridden, for example, for custom encryption or compression.
	 * @param exchange current HTTP request/response
	 * @param os the original OutputStream
	 * @return the potentially decorated OutputStream
	 * @throws java.io.IOException in case of I/O failure
	 */
	protected OutputStream decorateOutputStream(HttpExchange exchange, OutputStream os) throws IOException {
		return os;
	}

}