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org.jfree.report.modules.misc.bsf
Class BSFExpression

java.lang.Object
  |
  +--org.jfree.report.function.AbstractExpression
        |
        +--org.jfree.report.modules.misc.bsf.BSFExpression
public class BSFExpression
extends AbstractExpression
implements java.io.Serializable

An expression that uses the BeanShell scripting framework to perform a scripted calculation. The expression itself is contained in a function called

Object getValue()

and this function is defined in the expression property. You have to overwrite the function getValue() to begin and to end your expression, but you are free to add your own functions to the script.

By default, base Java core and extension packages are imported for you. They are:

An example in the XML format: (from report1.xml) 


 
 
 // you may import packages and classes or use the fully qualified name of the class
 import org.jfree.report.*;
 

 String userdefinedFunction (String parameter, Date date)
 {
 return parameter + " - the current date is " + date);
 }
 

 // use simple java code to perform the expression. You may use all classes
 // available in your classpath as if you write "real" java code in your favourite
 // IDE.
 // See the www.beanshell.org site for more information ...
 //
 // A return value of type "Object" is alway implied ...
 getValue ()
 {
 return userdefinedFunction ("Hello World :) ", new Date());
 }

Author:
Thomas Morgner
See Also:
Serialized Form

Constructor Summary
BSFExpression()
          default constructor, create a new BeanShellExpression.
 
Method Summary
 java.lang.Object clone()
          Clones the expression and reinitializes the script.
protected  org.apache.bsf.BSFManager createInterpreter()
           
 java.lang.String getExpression()
           
 java.lang.String getLanguage()
           
 java.lang.String getScript()
           
 java.lang.Object getValue()
          Evaluates the defined expression.
protected  void initializeInterpreter(org.apache.bsf.BSFManager interpreter)
           
protected  void invalidate()
           
 void setExpression(java.lang.String expression)
           
 void setLanguage(java.lang.String language)
           
 void setScript(java.lang.String script)
           
 
Methods inherited from class org.jfree.report.function.AbstractExpression
getDataRow, getDependencyLevel, getInstance, getName, getReportConfiguration, getResourceBundleFactory, getRuntime, isActive, setActive, setDependencyLevel, setName, 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()

initializeInterpreter

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

getValue

public java.lang.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 java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException
Clones the expression and reinitializes the script.
Overrides:
clone in class AbstractExpression
Returns:
a clone of the expression.
Throws:
java.lang.CloneNotSupportedException - this should never happen.

getExpression

public java.lang.String getExpression()

invalidate

protected void invalidate()

setExpression

public void setExpression(java.lang.String expression)

getLanguage

public java.lang.String getLanguage()

setLanguage

public void setLanguage(java.lang.String language)

getScript

public java.lang.String getScript()

setScript

public void setScript(java.lang.String script)
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