net.xoetrope.optional.scripts
Class ScriptAttributeEvaluator

java.lang.Object
  net.xoetrope.optional.scripts.ScriptAttributeEvaluator

All Implemented Interfaces:

XAttributeEvaluator

public class ScriptAttributeEvaluator
extends java.lang.Object
implements XAttributeEvaluator

Evaluates a script attribute by passing the scripts following the prefix 'script:' to the ScriptEngine. The scripts can be an a function that was predifined in the page Scripts tag or a script that is just being defined. eg. script:myFunction(); given that myFunction was define in the page Scripts tag. eg. script:out.println('Hello World'); the script is just being defined.

Copyright (c) Xoetrope Ltd., 2002-2007

License: see license.txt

Field Summary

protected java.util.Hashtable	classInstances The collection of class instances that are known to implement the methods of evaluated attributes
protected XProject	currentProject
protected XExceptionHandler	exceptionHandler
protected java.lang.Object	instance
protected java.lang.Object	result
protected ScriptEngine	scriptEngine

Constructor Summary

ScriptAttributeEvaluator()
Create a new instance of the evaluator

Method Summary

java.lang.Object	evaluateAttribute(java.lang.Object instance, java.lang.String attributeValue) Get the value of an attribute.
XMethodReference	getMethodReference(java.lang.Object instance, java.lang.String attributeValue) Get the value of an attribute by evaluating a method reference
XMethodReference	getMethodReference(java.lang.String attributeValue) Get the value of an attribute by evaluating a method reference
java.lang.Object	getObject() Get the current page.
java.lang.Object	getResult() Explicitly get the result of an evaluation.
void	setCurrentProject(XProject project) Set the current project and complete any initialization that depends on the project reference/instance.
void	setExceptionHandler(XExceptionHandler eh) Set an exception handler for processing exceptions
void	setResult(java.lang.Object value) Explicitly set the result of an evaluation.

Methods inherited from class java.lang.Object

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

Field Detail

classInstances

protected java.util.Hashtable classInstances

The collection of class instances that are known to implement the methods of evaluated attributes

instance

protected java.lang.Object instance

exceptionHandler

protected XExceptionHandler exceptionHandler

result

protected java.lang.Object result

currentProject

protected XProject currentProject

scriptEngine

protected ScriptEngine scriptEngine

Constructor Detail

ScriptAttributeEvaluator

public ScriptAttributeEvaluator()

Create a new instance of the evaluator

Method Detail

setCurrentProject

public void setCurrentProject(XProject project)

Set the current project and complete any initialization that depends on the project reference/instance.

Specified by:

setCurrentProject in interface XAttributeEvaluator

Parameters:

project - the current or owning project

evaluateAttribute

public java.lang.Object evaluateAttribute(java.lang.Object instance,
                                          java.lang.String attributeValue)

Get the value of an attribute.

Specified by:

evaluateAttribute in interface XAttributeEvaluator

Parameters:

page - the page being loaded

attributeValue - the raw value of the attribute

Returns:

the evaluated value of the attribute

getMethodReference

public XMethodReference getMethodReference(java.lang.String attributeValue)

Get the value of an attribute by evaluating a method reference

Specified by:

getMethodReference in interface XAttributeEvaluator

Parameters:

attributeValue - the method name

Returns:

the method reference or null if the referenced/named method cannot be found

getMethodReference

public XMethodReference getMethodReference(java.lang.Object instance,
                                           java.lang.String attributeValue)

Get the value of an attribute by evaluating a method reference

Specified by:

getMethodReference in interface XAttributeEvaluator

Parameters:

instance - the current page or object that provides the methods or fields used in the evaluation

attributeValue - the method name

Returns:

the method reference or null if the referenced/named method cannot be found

getObject

public java.lang.Object getObject()

Get the current page. In most cases this should correspond to the active page at the time the evaluator was last used, but no guarantees can be provided that multiple threads are not updating the value. The value should be retrieved and cached as soon as the evaluated method is entered as other method calls could have the side effect of reseting the value.

Returns:

the current page object

setExceptionHandler

public void setExceptionHandler(XExceptionHandler eh)

Set an exception handler for processing exceptions

Specified by:

setExceptionHandler in interface XAttributeEvaluator

Parameters:

eh - the exception handler

setResult

public void setResult(java.lang.Object value)

Explicitly set the result of an evaluation. This method may be used by an exception handler to override the result and set a sensible value in case of an exception

Specified by:

setResult in interface XAttributeEvaluator

Parameters:

the - new result value

getResult

public java.lang.Object getResult()

Explicitly get the result of an evaluation. This method may be used by an exception handler to determine the result and set a sensible value in case of an exception

Specified by:

getResult in interface XAttributeEvaluator

Returns:

the current/intermediate result value