nextapp.echoservlet.util
Class PeerFactory

java.lang.Object
  nextapp.echoservlet.util.PeerFactory

All Implemented Interfaces:

java.io.Serializable

public class PeerFactory

extends java.lang.Object

implements java.io.Serializable

Generates "peer" objects for objects based on associations. Associations are stored in a properties files, where the keys are the fully qualified class names of objects and the values are the fully qualified class names of their peers. When an object is passed to the createPeer() method its peer will be returned based on the bindings in the properties file. An objects superclass(es) will also be tested for available peers if none is available for the derived class. If no peer is found, a PeerFactoryException is thrown.

See Also:

Serialized Form

Nested Class Summary

class

PeerFactory.PeerFactoryException An exception used to describe a problem that was encountered loading a peer object.

Constructor Summary

PeerFactory()
Creates a new PeerFactory.

PeerFactory(java.lang.String propertiesFile)
Creates a new PeerFactory with initial associations.

Method Summary

void	addAssociation(java.lang.String className, java.lang.String peerClassName) Adds a single peer binding.
void	addAssociations(java.lang.String propertiesFile) Loads peer bindings.
java.lang.Object	createPeer(java.lang.Object object) Instantiates a new peer for the specified object by invoking its default constructor.
java.lang.Class	getPeerClass(java.lang.Class objectClass) Returns the peer class associated for the given object class.

Methods inherited from class java.lang.Object

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

Constructor Detail

PeerFactory

public PeerFactory()

Creates a new PeerFactory.

PeerFactory

public PeerFactory(java.lang.String propertiesFile)
            throws PeerFactory.PeerFactoryException

Creates a new PeerFactory with initial associations.

Parameters:

propertiesFile - The name for the properties file containing the initial peer bindings.

Method Detail

addAssociation

public void addAssociation(java.lang.String className,
                           java.lang.String peerClassName)

Adds a single peer binding.

Parameters:

className - The fully qualified name of the class.

peerClassName - The fully qualified name of the peer class.

addAssociations

public void addAssociations(java.lang.String propertiesFile)
                     throws PeerFactory.PeerFactoryException

Loads peer bindings. Invoking this method will result in the new associations supplementing existing associations. Existing associations will not be removed. If two associations have the same key, the most recently added one will be used.

Parameters:

propertiesFile - The name of a properties file containing the peer bindings to be loaded.

Throws:

PeerFactory.PeerFactoryException

createPeer

public java.lang.Object createPeer(java.lang.Object object)
                            throws PeerFactory.PeerFactoryException

Instantiates a new peer for the specified object by invoking its default constructor.

Parameters:

object - The object for which to create an peer instance.

Returns:

A new instance of the peer object for object.

Throws:

PeerFactory.PeerFactoryException - if the peer cannot be instantiated.

getPeerClass

public java.lang.Class getPeerClass(java.lang.Class objectClass)
                             throws PeerFactory.PeerFactoryException

Returns the peer class associated for the given object class.

Parameters:

objectClass - The Class of the object whose peer Class is to be determined.

Returns:

The Class of the corresponding peer.

Throws:

PeerFactory.PeerFactoryException - if the peer class cannot be determined.