Package net.sf.jasperreports.engine.fill

Class JREvaluator

java.lang.Object

net.sf.jasperreports.engine.fill.JREvaluator

All Implemented Interfaces:

DatasetExpressionEvaluator

Direct Known Subclasses:

DirectEvaluator, GroovyEvaluator, JavaScriptCompiledEvaluator, JavaScriptEvaluator

public abstract class JREvaluator
extends Object
implements DatasetExpressionEvaluator

Base class for the dynamically generated expression evaluator classes. This class also provides some built-in functions that will be described next.

Built-in Functions

Report expressions can perform method calls on various objects that are available during report filling, such as parameters, fields, or variable values, but can also call methods on a special object that is already available as the this reference. This is the calculator object. It has public utility methods that are ready to use inside report expressions.

Currently, there are only a few utility methods of the calculator object available as built-in functions inside report expressions. These are the following:

• msg - this function offers a convenient way to format messages based on the current report locale, just as you would normally do when using a java.text.MessageFormat instance. Furthermore, several signatures for this function take up to three message parameters in order to make the formatting functionality easier to use.
• str - this function is the equivalent of the $R{} syntax. It gives access to locale specific resources from the associated resource bundle.

Author:

Lucian Chirita (lucianc@users.sourceforge.net)

Field Summary

Fields

Modifier and Type	Field	Description
static final String	EXCEPTION_MESSAGE_KEY_RESOURCE_NOT_FOUND
protected boolean	ignoreNPE
static final String	PROPERTY_IGNORE_NPE	The expression evaluation engine in JasperReports has always ignored java.lang.NullPointerException exceptions raised during expression evaluation.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JREvaluator()	Default constructor.

Method Summary

Modifier and Type	Method	Description
protected abstract void	customizedInit(Map<String,JRFillParameter> parametersMap, Map<String,JRFillField> fieldsMap, Map<String,JRFillVariable> variablesMap)	Initializes the parameters, fields and variables of the evaluator.
protected abstract Object	evaluate(int id)	Evaluates an expression using current fields and variables values.
Object	evaluate(JRExpression expression)
protected abstract Object	evaluateEstimated(int id)	Evaluates an expression using estimated variables values.
Object	evaluateEstimated(JRExpression expression)
protected abstract Object	evaluateOld(int id)	Evaluates an expression using old fields and variables values.
Object	evaluateOld(JRExpression expression)
<T extends FunctionSupport> T	getFunctionSupport(Class<T> clazz)
protected Object	handleEvaluationException(JRExpression expression, Throwable e)
protected String	handleMissingResource(String key, Exception e)	Handles the case when a resource is missing.
void	init(Map<String,JRFillParameter> parametersMap, Map<String,JRFillField> fieldsMap, Map<String,JRFillVariable> variablesMap, WhenResourceMissingTypeEnum resourceMissingType, boolean ignoreNPE)	Initializes the evaluator by setting the parameter, field and variable objects.
String	msg(String pattern, Object arg0)	Constructs a message using a pattern with one parameter.
String	msg(String pattern, Object... args)	Constructs a message using a pattern with any number of parameters.
String	msg(String pattern, Object arg0, Object arg1)	Constructs a message using a pattern with two parameters.
String	msg(String pattern, Object arg0, Object arg1, Object arg2)	Constructs a message using a pattern with three parameters.
void	setDirectExpressionEvaluators(DirectExpressionEvaluators directExpressionEvaluators)
String	str(String key)	Returns a string for a given key from the resource bundle associated with the evaluator.

Methods inherited from class java.lang.Object

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

Field Details

EXCEPTION_MESSAGE_KEY_RESOURCE_NOT_FOUND

public static final String EXCEPTION_MESSAGE_KEY_RESOURCE_NOT_FOUND

See Also:

• Constant Field Values

PROPERTY_IGNORE_NPE

public static final String PROPERTY_IGNORE_NPE

The expression evaluation engine in JasperReports has always ignored java.lang.NullPointerException exceptions raised during expression evaluation. An expression raising NullPointerException is evaluated to null. However, in certain cases, users want to be able to track down the source of their NPE and this configuration property can be set to instruct the expression evaluation engine to treat NPEs just the way all other expression exceptions are treated. The default value of this configuration property is true, meaning NPEs are ignored. The property can be set globally, at report or at dataset level.

See Also:

• Constant Field Values

ignoreNPE

protected boolean ignoreNPE

Constructor Details

JREvaluator

protected JREvaluator()

Default constructor.

Method Details

setDirectExpressionEvaluators

public void setDirectExpressionEvaluators(DirectExpressionEvaluators directExpressionEvaluators)

init

public void init(Map<String,JRFillParameter> parametersMap,
 Map<String,JRFillField> fieldsMap,
 Map<String,JRFillVariable> variablesMap,
 WhenResourceMissingTypeEnum resourceMissingType,
 boolean ignoreNPE)
          throws JRException

Initializes the evaluator by setting the parameter, field and variable objects.

Specified by:

init in interface DatasetExpressionEvaluator

Parameters:

parametersMap - the parameters indexed by name

fieldsMap - the fields indexed by name

variablesMap - the variables indexed by name

resourceMissingType - the resource missing type

Throws:

JRException

getFunctionSupport

public <T extends FunctionSupport> T getFunctionSupport(Class<T> clazz)

msg

public String msg(String pattern,
 Object arg0)

Constructs a message using a pattern with one parameter.

Parameters:

pattern - the message pattern

arg0 - the message parameter

Returns:

the constructed message

See Also:

• MessageFormat.format(java.lang.Object[],java.lang.StringBuffer, java.text.FieldPosition)

msg

public String msg(String pattern,
 Object arg0,
 Object arg1)

Constructs a message using a pattern with two parameters.

Parameters:

pattern - the message pattern

arg0 - the first message parameter

arg1 - the second message parameter

Returns:

the constructed message

See Also:

• MessageFormat.format(java.lang.Object[],java.lang.StringBuffer, java.text.FieldPosition)

msg

public String msg(String pattern,
 Object arg0,
 Object arg1,
 Object arg2)

Constructs a message using a pattern with three parameters.

Parameters:

pattern - the message pattern

arg0 - the first message parameter

arg1 - the second message parameter

arg2 - the third parameter

Returns:

the constructed message

See Also:

• MessageFormat.format(java.lang.Object[],java.lang.StringBuffer, java.text.FieldPosition)

msg

public String msg(String pattern,
 Object... args)

Constructs a message using a pattern with any number of parameters.

Parameters:

pattern - the message pattern

args - the message parameters

Returns:

the constructed message

See Also:

• MessageFormat.format(java.lang.Object[],java.lang.StringBuffer, java.text.FieldPosition)

str

public String str(String key)

Returns a string for a given key from the resource bundle associated with the evaluator.

Parameters:

key - the key

Returns:

the string for the given key

See Also:

• ResourceBundle.getString(java.lang.String)

handleEvaluationException

protected Object handleEvaluationException(JRExpression expression,
 Throwable e)
                                    throws JRExpressionEvalException

Throws:

JRExpressionEvalException

evaluate

public Object evaluate(JRExpression expression)
                throws JRExpressionEvalException

Specified by:

evaluate in interface DatasetExpressionEvaluator

Throws:

JRExpressionEvalException

evaluateOld

public Object evaluateOld(JRExpression expression)
                   throws JRExpressionEvalException

Specified by:

evaluateOld in interface DatasetExpressionEvaluator

Throws:

JRExpressionEvalException

evaluateEstimated

public Object evaluateEstimated(JRExpression expression)
                         throws JRExpressionEvalException

Specified by:

evaluateEstimated in interface DatasetExpressionEvaluator

Throws:

JRExpressionEvalException

handleMissingResource

protected String handleMissingResource(String key,
 Exception e)
                                throws JRRuntimeException

Handles the case when a resource is missing.

Parameters:

key - the resource key

e - the exception

Returns:

the value to use for the resource

Throws:

JRRuntimeException - when the resource missing handling type is Error

customizedInit

protected abstract void customizedInit(Map<String,JRFillParameter> parametersMap,
 Map<String,JRFillField> fieldsMap,
 Map<String,JRFillVariable> variablesMap)
                                throws JRException

Initializes the parameters, fields and variables of the evaluator.

Parameters:

parametersMap - the parameters indexed by name

fieldsMap - the fields indexed by name

variablesMap - the variables indexed by name

Throws:

JRException

evaluate

protected abstract Object evaluate(int id)
                            throws Throwable

Evaluates an expression using current fields and variables values.

Parameters:

id - the expression id

Returns:

the result of the evaluation

Throws:

Throwable

See Also:

• JRExpression.EVALUATION_DEFAULT
• JRFillVariable.getValue()
• JRFillField.getValue()

evaluateOld

protected abstract Object evaluateOld(int id)
                               throws Throwable

Evaluates an expression using old fields and variables values.

Parameters:

id - the expression id

Returns:

the result of the evaluation

Throws:

Throwable

See Also:

• JRExpression.EVALUATION_OLD
• JRFillVariable.getOldValue()
• JRFillField.getOldValue()

evaluateEstimated

protected abstract Object evaluateEstimated(int id)
                                     throws Throwable

Evaluates an expression using estimated variables values.

Parameters:

id - the expression id

Returns:

the result of the evaluation

Throws:

Throwable

See Also:

• JRExpression.EVALUATION_ESTIMATED
• JRFillVariable.getEstimatedValue()