com.gwtplatform.dispatch.rpc.client.interceptor.caching

Class AbstractCachingRpcInterceptor<A,R>

java.lang.Object

com.gwtplatform.dispatch.client.interceptor.AbstractInterceptor<A,R>

com.gwtplatform.dispatch.rpc.client.interceptor.AbstractRpcInterceptor<A,R>

com.gwtplatform.dispatch.rpc.client.interceptor.caching.AbstractCachingRpcInterceptor<A,R>

Type Parameters:

A - The type of the action.

R - The type of the result.

All Implemented Interfaces:

Interceptor<A,R>, RpcInterceptor<A,R>

Direct Known Subclasses:

CachingInterceptor

public abstract class AbstractCachingRpcInterceptor<A,R>
extends AbstractRpcInterceptor<A,R>

Abstract base class for client-side interceptors with caching support.

Supported features include:

1. prefetch(A)/postfetch(A, R) perform the cache lookup and the cache store. You can use this to customize the caching logic.
2. Automatic action queuing so that calls in quick succession result in a single trip to the server.
3. Flexibility of cache implementation to support custom caching

Constructor Summary

Constructors

Constructor and Description
AbstractCachingRpcInterceptor(Class<A> actionType, Cache cache)

Method Summary

Modifier and Type	Method and Description
boolean	canExecute(com.gwtplatform.dispatch.shared.TypedAction<?> action)
com.gwtplatform.dispatch.shared.DispatchRequest	execute(A action, com.google.gwt.user.client.rpc.AsyncCallback<R> resultCallback, ExecuteCommand<A,R> executeCommand)
protected Cache	getCache()
protected abstract void	postfetch(A action, R result) Override this method to perform an action after the call to the server returns successfully or not.
protected abstract R	prefetch(A action) Override this method to perform an action before the call is sent to the server.
com.gwtplatform.dispatch.shared.DispatchRequest	undo(A action, R result, com.google.gwt.user.client.rpc.AsyncCallback<Void> callback, UndoCommand<A,R> undoCommand) Undoes the specified action if supported.

Methods inherited from class com.gwtplatform.dispatch.client.interceptor.AbstractInterceptor

getActionType

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.gwtplatform.dispatch.client.interceptor.Interceptor

getActionType

Constructor Detail

AbstractCachingRpcInterceptor

public AbstractCachingRpcInterceptor(Class<A> actionType,
                                     Cache cache)

Method Detail

execute

public com.gwtplatform.dispatch.shared.DispatchRequest execute(A action,
                                                               com.google.gwt.user.client.rpc.AsyncCallback<R> resultCallback,
                                                               ExecuteCommand<A,R> executeCommand)

undo

public com.gwtplatform.dispatch.shared.DispatchRequest undo(A action,
                                                            R result,
                                                            com.google.gwt.user.client.rpc.AsyncCallback<Void> callback,
                                                            UndoCommand<A,R> undoCommand)

Description copied from interface: RpcInterceptor

Undoes the specified action if supported.

If the interceptor makes asynchronous calls, it is recommended that you confirm that this request has not been cancelled after returning by calling DelegatingDispatchRequest.isPending() against the request parameter.

Parameters:

action - The action to undo.

result - The result to undo.

callback - The callback to use to indicate when the action has been undone. Unless the request is cancelled, you must invoke AsyncCallback.onSuccess(T) on this callback when you have successfully undone the action. If any failure occurs call AsyncCallback.onFailure(java.lang.Throwable).

undoCommand - Call UndoCommand.undo(Object, Object, com.google.gwt.user.client.rpc.AsyncCallback) on this object to send the action over to the server via gwt-rpc. As a parameter you can pass callback or your custom AsyncCallback if you want to perform any processing following the undo.

Returns:

A DispatchRequest object. Never return null, instead return a new CompletedDispatchRequest if you executed, cancelled or ignored the action.

prefetch

protected abstract R prefetch(A action)

Override this method to perform an action before the call is sent to the server. If the call returns a non-null result then the action is never executed on the server and the returned value is used. If the call returns null then the action is executed on the server.

You can use this method to fetch the action from the cache.

Parameters:

action - The action to be prefetched

Returns:

The prefetched result. If not found, return null.

postfetch

protected abstract void postfetch(A action,
                                  R result)

Override this method to perform an action after the call to the server returns successfully or not. If the call succeeded, the result will be passed, if it failed null will be passed in the result parameter.

You can use this method to add the result to cache, if it is null you should remove the action from the cache.

Parameters:

action - The action that just finished execution on the server.

result - The result after the server call, or null if the server call failed.

getCache

protected Cache getCache()

Returns:

the cache

canExecute

public boolean canExecute(com.gwtplatform.dispatch.shared.TypedAction<?> action)

Specified by:

canExecute in interface Interceptor<A,R>

Overrides:

canExecute in class AbstractRpcInterceptor<A,R>