Package org.pentaho.reporting.engine.classic.core.modules.misc.bsf

Class BSFExpression

java.lang.Object

org.pentaho.reporting.engine.classic.core.function.AbstractExpression

org.pentaho.reporting.engine.classic.core.modules.misc.bsf.BSFExpression

All Implemented Interfaces:

Serializable, Cloneable, Expression

public class BSFExpression
extends AbstractExpression

An expression that uses the Bean scripting framework to perform a scripted calculation.

Author:

Thomas Morgner

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
BSFExpression()	Default constructor, create a new BeanShellExpression.

Method Summary

Modifier and Type	Method	Description
Object	clone()	Clones the expression and reinitializes the script.
protected org.apache.bsf.BSFManager	createInterpreter()	Creates a new interpreter instance.
String	getExpression()	Returns the script that gets evaluated every time the getValue() method is called.
String	getLanguage()	Returns the programming language, in which the interpreter work.
String	getScript()	Returns the script.
Object	getValue()	Evaluates the defined expression.
protected void	initializeInterpreter(org.apache.bsf.BSFManager interpreter)	Initializes the Bean-Scripting Framework manager.
protected void	invalidate()	Invalidates the interpreter-cache and forces a reinterpretation of the script.
void	setExpression(String expression)	Sets the script that should be executed.
void	setLanguage(String language)	Defines the programming language of the script and expression.
void	setScript(String script)	Defines the script.

Methods inherited from class org.pentaho.reporting.engine.classic.core.function.AbstractExpression

getDataRow, getDependencyLevel, getInstance, getName, getReportConfiguration, getResourceBundleFactory, getRuntime, isActive, isDeepTraversing, isPreserve, setActive, setDependencyLevel, setName, setPreserve, setRuntime

Methods inherited from class java.lang.Object

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

Constructor Detail

BSFExpression

public BSFExpression()

Default constructor, create a new BeanShellExpression.

Method Detail

createInterpreter

protected org.apache.bsf.BSFManager createInterpreter()

Creates a new interpreter instance.

Returns:

the interpreter or null, if there was an error.

initializeInterpreter

protected void initializeInterpreter(org.apache.bsf.BSFManager interpreter)
                              throws org.apache.bsf.BSFException

Initializes the Bean-Scripting Framework manager.

Parameters:

interpreter - the BSF-Manager that should be initialized.

Throws:

org.apache.bsf.BSFException - if an error occured.

getValue

public Object getValue()

Evaluates the defined expression. If an exception or an evaluation error occures, the evaluation returns null and the error is logged. The current datarow and a copy of the expressions properties are set to script-internal variables. Changes to the properties will not alter the expressions original properties and will be lost when the evaluation is finished.

Expressions do not maintain a state and no assumptions about the order of evaluation can be made.

Returns:

the evaluated value or null.

clone

public Object clone()
             throws CloneNotSupportedException

Clones the expression and reinitializes the script.

Specified by:

clone in interface Expression

Overrides:

clone in class AbstractExpression

Returns:

a clone of the expression.

Throws:

CloneNotSupportedException - this should never happen.

getExpression

public String getExpression()

Returns the script that gets evaluated every time the getValue() method is called.

Returns:

the script.

invalidate

protected void invalidate()

Invalidates the interpreter-cache and forces a reinterpretation of the script.

setExpression

public void setExpression(String expression)

Sets the script that should be executed. Whats in the script depends on what langage is selected.

Parameters:

expression - the script.

getLanguage

public String getLanguage()

Returns the programming language, in which the interpreter work.

Returns:

the programming language, which must be one of the supported BSF-Languages.

setLanguage

public void setLanguage(String language)

Defines the programming language of the script and expression.

Parameters:

language - the programming language of the script.

getScript

public String getScript()

Returns the script. The script is a predefined piece of code that gets executed once. It can (and should) be used to perform global initializations and to define functions.

Returns:

the script (can be null).

setScript

public void setScript(String script)

Defines the script. The script is a predefined piece of code that gets executed once. It can (and should) be used to perform global initializations and to define functions.

Parameters:

script - an initialization script.