org.gwtwidgets.server.spring
Class GWTRPCServiceExporter

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          com.google.gwt.user.server.rpc.RemoteServiceServlet
              org.gwtwidgets.server.spring.GWTRPCServiceExporter

All Implemented Interfaces:

com.google.gwt.user.server.rpc.SerializationPolicyProvider, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig, org.springframework.beans.factory.InitializingBean, org.springframework.web.context.ServletContextAware, org.springframework.web.HttpRequestHandler

public class GWTRPCServiceExporter
extends com.google.gwt.user.server.rpc.RemoteServiceServlet
implements org.springframework.web.HttpRequestHandler, org.springframework.beans.factory.InitializingBean, org.springframework.web.context.ServletContextAware

This component publishes an object (see setService(Object)) as a service to the GWT RPC protocol. Service targets can be:

• POJOs which don't have to extend any class or implement any interface. However you should provide a service interface (see setServiceInterfaces(Class[]))
• POJOs which implement RemoteService
• You can extend the GWTRPCServiceExporter which assigns the target service to itself.

Exceptions directly thrown from the target service are propagated back to the client. For special exception handling you can override the various handle* methods which are invoked by the GWTRPCServiceExporter.

Author:

George Georgovassilis, g.georgovassilis[at]gmail.com, Max Jonas Werner

See Also:

Serialized Form

Field Summary

static int	COMPRESSION_AUTO Leave default RPC response compression behavior.
static int	COMPRESSION_DISABLED Disable RPC response compression.
static int	COMPRESSION_ENABLED Force compression of all RPC responses.
protected int	compressResponse
protected org.apache.commons.logging.Log	logger
protected java.util.Map<java.lang.reflect.Method,java.lang.reflect.Method>	methodCache
protected java.lang.Object	service
protected java.lang.Class<?>[]	serviceInterfaces
protected javax.servlet.ServletContext	servletContext

Constructor Summary

GWTRPCServiceExporter()

Method Summary

void	afterPropertiesSet()
protected java.lang.reflect.Method	getMethodToInvoke(java.lang.reflect.Method decodedMethod) Returns method to invoke on service.
static javax.servlet.http.HttpServletRequest	getRequest() Deprecated. Use ServletUtils.getRequest()
static javax.servlet.http.HttpServletResponse	getResponse() Deprecated. Use ServletUtils.getResponse()
java.lang.Object	getService() Return target service.
javax.servlet.ServletContext	getServletContext()
protected java.lang.String	handleExporterProcessingException(java.lang.Exception e) Invoked by processCall(String) for an exception if no suitable exception handler was found.
protected java.lang.String	handleIllegalAccessException(java.lang.IllegalAccessException e, java.lang.Object service, java.lang.reflect.Method targetMethod, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles an exception which is raised when a method access is attempted to a method which is not part of the RPC interface.
protected java.lang.String	handleIllegalArgumentException(java.lang.IllegalArgumentException e, java.lang.Object service, java.lang.reflect.Method targetMethod, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles an exception which is raised when a method invocation with bad arguments is attempted.
protected java.lang.String	handleIncompatibleRemoteServiceException(com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException e) Invoked by processCall(String) when RPC throws an IncompatibleRemoteServiceException.
protected java.lang.String	handleInvocationTargetException(java.lang.reflect.InvocationTargetException e, java.lang.Object service, java.lang.reflect.Method targetMethod, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles exceptions thrown by the target service, which are wrapped in InvocationTargetExceptions due to invocation by reflection.
void	handleRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
protected java.lang.String	handleServiceException(java.lang.Exception e, java.lang.Object service, java.lang.reflect.Method targetMethod, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles exceptions thrown during a service invocation that are not handled by other exception handlers.
protected java.lang.String	handleUndeclaredThrowableException(java.lang.Exception e, java.lang.Object service, java.lang.reflect.Method targetMethod, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles UndeclaredThrowableExceptions which are thrown by the target service.
protected java.lang.String	invokeMethodOnService(java.lang.Object service, java.lang.reflect.Method targetMethod, java.lang.Object[] targetParameters, com.google.gwt.user.server.rpc.RPCRequest rpcRequest) Handles method invocation on a service and is invoked by processCall(String).
protected void	onAfterResponseSerialized(java.lang.String serializedResponse)
protected void	onBeforeRequestDeserialized(java.lang.String serializedRequest)
java.lang.String	processCall(java.lang.String payload) Overridden from RemoteServiceServlet and invoked by the servlet code.
protected void	setCompressResponse(int compressResponse) Enables or disables compression of RPC output.
void	setService(java.lang.Object service) Set the service service.
void	setServiceInterfaces(java.lang.Class<?>[] serviceInterfaces) Specifies the interfaces which must be implemented by the service bean.
void	setServletContext(javax.servlet.ServletContext servletContext) Implementation of ServletContextAware, is invoked by the Spring application context.
protected boolean	shouldCompressResponse(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.String responsePayload)

Methods inherited from class com.google.gwt.user.server.rpc.RemoteServiceServlet

doGetSerializationPolicy, doPost, doUnexpectedFailure, getSerializationPolicy, getThreadLocalRequest, getThreadLocalResponse

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletInfo, getServletName, init, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

COMPRESSION_DISABLED

public static final int COMPRESSION_DISABLED

Disable RPC response compression. Value is 0.

See Also:

Constant Field Values

COMPRESSION_AUTO

public static final int COMPRESSION_AUTO

Leave default RPC response compression behavior. Value is 1.

See Also:

Constant Field Values

COMPRESSION_ENABLED

public static final int COMPRESSION_ENABLED

Force compression of all RPC responses. Value is 2.

See Also:

Constant Field Values

logger

protected org.apache.commons.logging.Log logger

serviceInterfaces

protected java.lang.Class<?>[] serviceInterfaces

service

protected java.lang.Object service

servletContext

protected javax.servlet.ServletContext servletContext

compressResponse

protected int compressResponse

methodCache

protected java.util.Map<java.lang.reflect.Method,java.lang.reflect.Method> methodCache

Constructor Detail

GWTRPCServiceExporter

public GWTRPCServiceExporter()

Method Detail

setServletContext

public void setServletContext(javax.servlet.ServletContext servletContext)

Implementation of ServletContextAware, is invoked by the Spring application context.

Specified by:

setServletContext in interface org.springframework.web.context.ServletContextAware

Parameters:

servletContext -

getServletContext

public javax.servlet.ServletContext getServletContext()

Specified by:

getServletContext in interface javax.servlet.ServletConfig

Overrides:

getServletContext in class javax.servlet.GenericServlet

getRequest

public static javax.servlet.http.HttpServletRequest getRequest()

Deprecated. Use ServletUtils.getRequest()

Return the request which invokes the service. Valid only if used in the dispatching thread.

Returns:

the servlet request

getResponse

public static javax.servlet.http.HttpServletResponse getResponse()

Deprecated. Use ServletUtils.getResponse()

Return the response which accompanies the request. Valid only if used in the dispatching thread.

Returns:

the servlet response

onAfterResponseSerialized

protected void onAfterResponseSerialized(java.lang.String serializedResponse)

Overrides:

onAfterResponseSerialized in class com.google.gwt.user.server.rpc.RemoteServiceServlet

onBeforeRequestDeserialized

protected void onBeforeRequestDeserialized(java.lang.String serializedRequest)

Overrides:

onBeforeRequestDeserialized in class com.google.gwt.user.server.rpc.RemoteServiceServlet

invokeMethodOnService

protected java.lang.String invokeMethodOnService(java.lang.Object service,
                                                 java.lang.reflect.Method targetMethod,
                                                 java.lang.Object[] targetParameters,
                                                 com.google.gwt.user.server.rpc.RPCRequest rpcRequest)
                                          throws java.lang.Exception

Handles method invocation on a service and is invoked by processCall(String).

Parameters:

service - Service to invoke method on

targetMethod - Method to invoke.

targetParameters - Parameters to pass to method. Can be null for no arguments.

rpcRequest - RPCRequest instance for this request

Returns:

Return RPC encoded result.

Throws:

java.lang.Exception

handleIllegalArgumentException

protected java.lang.String handleIllegalArgumentException(java.lang.IllegalArgumentException e,
                                                          java.lang.Object service,
                                                          java.lang.reflect.Method targetMethod,
                                                          com.google.gwt.user.server.rpc.RPCRequest rpcRequest)

Handles an exception which is raised when a method invocation with bad arguments is attempted. This implementation throws a SecurityException. For details on arguments please consult invokeMethodOnService(Object, Method, Object[], RPCRequest).

Parameters:

e - Exception thrown

service -

targetMethod -

Returns:

RPC encoded response (such as an RPC client exception)

handleIllegalAccessException

protected java.lang.String handleIllegalAccessException(java.lang.IllegalAccessException e,
                                                        java.lang.Object service,
                                                        java.lang.reflect.Method targetMethod,
                                                        com.google.gwt.user.server.rpc.RPCRequest rpcRequest)

Handles an exception which is raised when a method access is attempted to a method which is not part of the RPC interface. This method is invoked by processCall(String). This implementation throws a SecurityException. For details on arguments please consult invokeMethodOnService(Object, Method, Object[], RPCRequest).

Parameters:

e - Exception thrown

service -

targetMethod -

Returns:

RPC encoded response (such as an RPC client exception)

handleInvocationTargetException

protected java.lang.String handleInvocationTargetException(java.lang.reflect.InvocationTargetException e,
                                                           java.lang.Object service,
                                                           java.lang.reflect.Method targetMethod,
                                                           com.google.gwt.user.server.rpc.RPCRequest rpcRequest)
                                                    throws java.lang.Exception

Handles exceptions thrown by the target service, which are wrapped in InvocationTargetExceptions due to invocation by reflection. This method is invoked by processCall(String). This implementation encodes exceptions as RPC errors and returns them. For details on arguments please consult invokeMethodOnService(Object, Method, Object[], RPCRequest).

Parameters:

e - Exception thrown

service -

targetMethod -

rpcRequest -

Returns:

RPC payload

Throws:

java.lang.Exception

handleServiceException

protected java.lang.String handleServiceException(java.lang.Exception e,
                                                  java.lang.Object service,
                                                  java.lang.reflect.Method targetMethod,
                                                  com.google.gwt.user.server.rpc.RPCRequest rpcRequest)
                                           throws java.lang.Exception

Handles exceptions thrown during a service invocation that are not handled by other exception handlers. processCall(String) on exceptions which have escaped the other exception handlers such as handleIllegalAccessException(IllegalAccessException, Object, Method, RPCRequest) etc. This implementation re-casts 'e'. For details on arguments please consult invokeMethodOnService(Object, Method, Object[], RPCRequest).

Parameters:

e - Exception thrown

service -

targetMethod -

rpcRequest -

Returns:

RPC payload

Throws:

java.lang.Exception

handleUndeclaredThrowableException

protected java.lang.String handleUndeclaredThrowableException(java.lang.Exception e,
                                                              java.lang.Object service,
                                                              java.lang.reflect.Method targetMethod,
                                                              com.google.gwt.user.server.rpc.RPCRequest rpcRequest)
                                                       throws java.lang.Exception

Handles UndeclaredThrowableExceptions which are thrown by the target service. This method This method is invoked by processCall(String). This implementation re-casts 'e'. For details on arguments please consult invokeMethodOnService(Object, Method, Object[], RPCRequest).

Parameters:

e - Exception thrown

service -

targetMethod -

rpcRequest -

Returns:

RPC payload

Throws:

java.lang.Exception

getMethodToInvoke

protected java.lang.reflect.Method getMethodToInvoke(java.lang.reflect.Method decodedMethod)
                                              throws java.lang.NoSuchMethodException

Returns method to invoke on service. This implementation calls ReflectionUtils.getRPCMethod(Object, Class[], Method)

Parameters:

decodedMethod - Method as determined by RPC

Returns:

Throws:

java.lang.NoSuchMethodException

processCall

public java.lang.String processCall(java.lang.String payload)
                             throws com.google.gwt.user.client.rpc.SerializationException

Overridden from RemoteServiceServlet and invoked by the servlet code.

Overrides:

processCall in class com.google.gwt.user.server.rpc.RemoteServiceServlet

Throws:

com.google.gwt.user.client.rpc.SerializationException

handleIncompatibleRemoteServiceException

protected java.lang.String handleIncompatibleRemoteServiceException(com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException e)
                                                             throws com.google.gwt.user.client.rpc.SerializationException

Invoked by processCall(String) when RPC throws an IncompatibleRemoteServiceException. This implementation propagates the exception back to the client via RPC.

Parameters:

e - Exception thrown

Returns:

RPC encoded failure response

Throws:

com.google.gwt.user.client.rpc.SerializationException

handleExporterProcessingException

protected java.lang.String handleExporterProcessingException(java.lang.Exception e)

Invoked by processCall(String) for an exception if no suitable exception handler was found. This is the outermost exception handler, catching any exceptions not caught by other exception handlers or even thrown by those handlers. This implementation wraps 'e' in a RuntimeException which is then thrown.

Parameters:

e -

Returns:

RPC encoded failure response

setService

public void setService(java.lang.Object service)

Set the service service. RPC requests are decoded and the corresponding method of the service object is invoked.

Parameters:

service -

handleRequest

public void handleRequest(javax.servlet.http.HttpServletRequest request,
                          javax.servlet.http.HttpServletResponse response)
                   throws javax.servlet.ServletException,
                          java.io.IOException

Specified by:

handleRequest in interface org.springframework.web.HttpRequestHandler

Throws:

javax.servlet.ServletException

java.io.IOException

setServiceInterfaces

public void setServiceInterfaces(java.lang.Class<?>[] serviceInterfaces)

Specifies the interfaces which must be implemented by the service bean. If not specified then any interface extending RemoteService which is implemented by the service bean is assumed.

Parameters:

serviceInterfaces -

afterPropertiesSet

public void afterPropertiesSet()
                        throws java.lang.Exception

Specified by:

afterPropertiesSet in interface org.springframework.beans.factory.InitializingBean

Throws:

java.lang.Exception

getService

public java.lang.Object getService()

Return target service. Each GWTRPCServiceExporter has a single target service which it redirects RPC to.

Returns:

Object

shouldCompressResponse

protected boolean shouldCompressResponse(javax.servlet.http.HttpServletRequest request,
                                         javax.servlet.http.HttpServletResponse response,
                                         java.lang.String responsePayload)

Overrides:

shouldCompressResponse in class com.google.gwt.user.server.rpc.RemoteServiceServlet

setCompressResponse

protected void setCompressResponse(int compressResponse)

Enables or disables compression of RPC output. Defaults to COMPRESSION_AUTO. Allowed values are COMPRESSION_ENABLED, COMPRESSION_DISABLED and COMPRESSION_AUTO.

Parameters:

compressResponse -