org.sapia.resource
Class ResourceHandlerChain

java.lang.Object
  org.sapia.resource.ResourceHandlerChain

All Implemented Interfaces:

ResourceCapable

public class ResourceHandlerChain
extends java.lang.Object
implements ResourceCapable

This class implements a chain of responsibility: an instance of this class holds a list of ResourceHandler instances. The instances are traversed when client application request a specific handler, given a URI.

Author:

Yanick Duchesne

Constructor Summary

ResourceHandlerChain()

Method Summary

void	append(ResourceHandler handler) Adds a resource handler to the end of the list that this instance holds.
protected ResourceHandler	doSelect(java.lang.String uri)
void	prepend(ResourceHandler handler) Adds a resource handler to the beginning of the list that this instance holds.
Resource	resolveResource(java.lang.String uri)
ResourceHandler	select(java.lang.String uri) Selects a ResourceHandler from this instance and returns it.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceHandlerChain

public ResourceHandlerChain()

Method Detail

prepend

public void prepend(ResourceHandler handler)

Adds a resource handler to the beginning of the list that this instance holds.

Parameters:

handler - a ResourceHandler.

append

public void append(ResourceHandler handler)

Adds a resource handler to the end of the list that this instance holds.

Parameters:

handler - a ResourceHandler.

resolveResource

public Resource resolveResource(java.lang.String uri)
                         throws ResourceNotFoundException,
                                java.io.IOException

Specified by:

resolveResource in interface ResourceCapable

Throws:

ResourceNotFoundException

java.io.IOException

select

public ResourceHandler select(java.lang.String uri)

Selects a ResourceHandler from this instance and returns it. The handler is chose based on the given URI.

This instance traverses its handlers, calling the accepts() method on them (the method takes the given URI as a parameter). The first handler that "accepts" the URI (by returning true) is returned to the caller. If no handler as accepted the URI, null is returned.

Parameters:

uri - a URI.

Returns:

a ResourceHandler , or null if no handler could be found for the given URI.

doSelect

protected ResourceHandler doSelect(java.lang.String uri)