org.springframework.remoting.httpinvoker
Class HttpInvokerServiceExporter

java.lang.Object
  org.springframework.remoting.support.RemoteExporter
      org.springframework.remoting.support.RemoteInvocationBasedExporter
          org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter

All Implemented Interfaces:

BeanClassLoaderAware, InitializingBean, HttpRequestHandler

public class HttpInvokerServiceExporter
extends RemoteInvocationBasedExporter
implements HttpRequestHandler, InitializingBean

HTTP request handler that exports the specified service bean as HTTP invoker service endpoint, accessible via an HTTP invoker proxy.

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.

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.

Since:

1.1

Author:

Juergen Hoeller

See Also:

HttpInvokerClientInterceptor, HttpInvokerProxyFactoryBean, RmiServiceExporter, HessianServiceExporter, BurlapServiceExporter

Field Summary

static String

CONTENT_TYPE_SERIALIZED_OBJECT Default content type: "application/x-java-serialized-object"

Fields inherited from class org.springframework.remoting.support.RemoteExporter

logger

Constructor Summary

HttpInvokerServiceExporter()

Method Summary

void	afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
protected ObjectInputStream	createObjectInputStream(InputStream is) Create an ObjectInputStream for the given InputStream.
protected ObjectOutputStream	createObjectOutputStream(OutputStream os) Create an ObjectOutputStream for the given OutputStream.
protected InputStream	decorateInputStream(HttpServletRequest request, InputStream is) Return the InputStream to use for reading remote invocations, potentially decorating the given original InputStream.
protected OutputStream	decorateOutputStream(HttpServletRequest request, HttpServletResponse response, OutputStream os) Return the OutputStream to use for writing remote invocation results, potentially decorating the given original OutputStream.
protected RemoteInvocation	doReadRemoteInvocation(ObjectInputStream ois) Perform the actual reading of an invocation result object from the given ObjectInputStream.
protected void	doWriteRemoteInvocationResult(RemoteInvocationResult result, ObjectOutputStream oos) Perform the actual writing of the given invocation result object to the given ObjectOutputStream.
String	getContentType() Return the content type to use for sending HTTP invoker responses.
void	handleRequest(HttpServletRequest request, HttpServletResponse response) Reads a remote invocation from the request, executes it, and writes the remote invocation result to the response.
void	prepare() Initialize this service exporter.
protected RemoteInvocation	readRemoteInvocation(HttpServletRequest request) Read a RemoteInvocation from the given HTTP request.
protected RemoteInvocation	readRemoteInvocation(HttpServletRequest request, InputStream is) Deserialize a RemoteInvocation object from the given InputStream.
void	setContentType(String contentType) Specify the content type to use for sending HTTP invoker responses.
protected void	writeRemoteInvocationResult(HttpServletRequest request, HttpServletResponse response, RemoteInvocationResult result) Write the given RemoteInvocationResult to the given HTTP response.
protected void	writeRemoteInvocationResult(HttpServletRequest request, HttpServletResponse response, RemoteInvocationResult result, OutputStream os) Serialize the given RemoteInvocation to the given OutputStream.

Methods inherited from class org.springframework.remoting.support.RemoteInvocationBasedExporter

getRemoteInvocationExecutor, invoke, invokeAndCreateResult, setRemoteInvocationExecutor

Methods inherited from class org.springframework.remoting.support.RemoteExporter

checkService, checkServiceInterface, getExporterName, getProxyForService, getService, getServiceInterface, isRegisterTraceInterceptor, setBeanClassLoader, setRegisterTraceInterceptor, setService, setServiceInterface

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONTENT_TYPE_SERIALIZED_OBJECT

public static final String CONTENT_TYPE_SERIALIZED_OBJECT

Default content type: "application/x-java-serialized-object"

See Also:

Constant Field Values

Constructor Detail

HttpInvokerServiceExporter

public HttpInvokerServiceExporter()

Method Detail

setContentType

public void setContentType(String contentType)

Specify the content type to use for sending HTTP invoker responses.

Default is "application/x-java-serialized-object".

getContentType

public String getContentType()

Return the content type to use for sending HTTP invoker responses.

afterPropertiesSet

public void afterPropertiesSet()

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

prepare

public void prepare()

Initialize this service exporter.

handleRequest

public void handleRequest(HttpServletRequest request,
                          HttpServletResponse response)
                   throws ServletException,
                          IOException

Reads a remote invocation from the request, executes it, and writes the remote invocation result to the response.

Specified by:

handleRequest in interface HttpRequestHandler

Parameters:

request - current HTTP request

response - current HTTP response

Throws:

ServletException - in case of general errors

IOException - in case of I/O errors

See Also:

readRemoteInvocation(HttpServletRequest), RemoteInvocationBasedExporter.invokeAndCreateResult(org.springframework.remoting.support.RemoteInvocation, Object), writeRemoteInvocationResult(HttpServletRequest, HttpServletResponse, RemoteInvocationResult)

readRemoteInvocation

protected RemoteInvocation readRemoteInvocation(HttpServletRequest request)
                                         throws IOException,
                                                ClassNotFoundException

Read a RemoteInvocation from the given HTTP request.

Delegates to readRemoteInvocation(javax.servlet.http.HttpServletRequest, java.io.InputStream) with the servlet request's input stream.

Parameters:

request - current HTTP request

Returns:

the RemoteInvocation object

Throws:

IOException - in case of I/O failure

ClassNotFoundException - if thrown by deserialization

readRemoteInvocation

protected RemoteInvocation readRemoteInvocation(HttpServletRequest request,
                                                InputStream is)
                                         throws IOException,
                                                ClassNotFoundException

Deserialize a RemoteInvocation object from the given InputStream.

Gives decorateInputStream(javax.servlet.http.HttpServletRequest, java.io.InputStream) a chance to decorate the stream first (for example, for custom encryption or compression). Creates a CodebaseAwareObjectInputStream and calls doReadRemoteInvocation(java.io.ObjectInputStream) to actually read the object.

Can be overridden for custom serialization of the invocation.

Parameters:

request - current HTTP request

is - the InputStream to read from

Returns:

the RemoteInvocation object

Throws:

IOException - in case of I/O failure

ClassNotFoundException - if thrown during deserialization

decorateInputStream

protected InputStream decorateInputStream(HttpServletRequest request,
                                          InputStream is)
                                   throws IOException

Return the InputStream to use for reading remote invocations, potentially decorating the given original InputStream.

The default implementation returns the given stream as-is. Can be overridden, for example, for custom encryption or compression.

Parameters:

request - current HTTP request

is - the original InputStream

Returns:

the potentially decorated InputStream

Throws:

IOException - in case of I/O failure

createObjectInputStream

protected ObjectInputStream createObjectInputStream(InputStream is)
                                             throws IOException

Create an ObjectInputStream for the given InputStream.

The default implementation creates a Spring CodebaseAwareObjectInputStream.

Spring's CodebaseAwareObjectInputStream is used to explicitly resolve primitive class names. This is done by the standard ObjectInputStream on JDK 1.4+, but needs to be done explicitly on JDK 1.3.

Parameters:

is - the InputStream to read from

Returns:

the new ObjectInputStream instance to use

Throws:

IOException - if creation of the ObjectInputStream failed

doReadRemoteInvocation

protected RemoteInvocation doReadRemoteInvocation(ObjectInputStream ois)
                                           throws IOException,
                                                  ClassNotFoundException

Perform the actual reading of an invocation result object from the given ObjectInputStream.

The default implementation simply calls ObjectInputStream.readObject(). Can be overridden for deserialization of a custom wrapper object rather than the plain invocation, for example an encryption-aware holder.

Parameters:

ois - the ObjectInputStream to read from

Returns:

the RemoteInvocationResult object

Throws:

IOException - in case of I/O failure

ClassNotFoundException - if case of a transferred class not being found in the local ClassLoader

writeRemoteInvocationResult

protected void writeRemoteInvocationResult(HttpServletRequest request,
                                           HttpServletResponse response,
                                           RemoteInvocationResult result)
                                    throws IOException

Write the given RemoteInvocationResult to the given HTTP response.

Parameters:

request - current HTTP request

response - current HTTP response

result - the RemoteInvocationResult object

Throws:

IOException - in case of I/O failure

writeRemoteInvocationResult

protected void writeRemoteInvocationResult(HttpServletRequest request,
                                           HttpServletResponse response,
                                           RemoteInvocationResult result,
                                           OutputStream os)
                                    throws IOException

Serialize the given RemoteInvocation to the given OutputStream.

The default implementation gives decorateOutputStream(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.io.OutputStream) a chance to decorate the stream first (for example, for custom encryption or compression). Creates an ObjectOutputStream for the final stream and calls doWriteRemoteInvocationResult(org.springframework.remoting.support.RemoteInvocationResult, java.io.ObjectOutputStream) to actually write the object.

Can be overridden for custom serialization of the invocation.

Parameters:

request - current HTTP request

response - current HTTP response

result - the RemoteInvocationResult object

os - the OutputStream to write to

Throws:

IOException - in case of I/O failure

See Also:

decorateOutputStream(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.io.OutputStream), doWriteRemoteInvocationResult(org.springframework.remoting.support.RemoteInvocationResult, java.io.ObjectOutputStream)

decorateOutputStream

protected OutputStream decorateOutputStream(HttpServletRequest request,
                                            HttpServletResponse response,
                                            OutputStream os)
                                     throws IOException

Return the OutputStream to use for writing remote invocation results, potentially decorating the given original OutputStream.

The default implementation returns the given stream as-is. Can be overridden, for example, for custom encryption or compression.

Parameters:

request - current HTTP request

response - current HTTP response

os - the original OutputStream

Returns:

the potentially decorated OutputStream

Throws:

IOException - in case of I/O failure

createObjectOutputStream

protected ObjectOutputStream createObjectOutputStream(OutputStream os)
                                               throws IOException

Create an ObjectOutputStream for the given OutputStream.

The default implementation creates a plain ObjectOutputStream.

Parameters:

os - the OutputStream to write to

Returns:

the new ObjectOutputStream instance to use

Throws:

IOException - if creation of the ObjectOutputStream failed

doWriteRemoteInvocationResult

protected void doWriteRemoteInvocationResult(RemoteInvocationResult result,
                                             ObjectOutputStream oos)
                                      throws IOException

Perform the actual writing of the given invocation result object to the given ObjectOutputStream.

The default implementation simply calls ObjectOutputStream.writeObject(java.lang.Object). Can be overridden for serialization of a custom wrapper object rather than the plain invocation, for example an encryption-aware holder.

Parameters:

result - the RemoteInvocationResult object

oos - the ObjectOutputStream to write to

Throws:

IOException - if thrown by I/O methods