org.apache.taglibs.standard.lang.support

Class ExpressionEvaluatorManager

java.lang.Object

org.apache.taglibs.standard.lang.support.ExpressionEvaluatorManager

public class ExpressionEvaluatorManager
extends Object

A conduit to the JSTL EL. Based on...

An implementation of the ExpressionEvaluatorManager called for by the JSTL rev1 draft. This class is responsible for delegating a request for expression evaluating to the particular, "active" ExpressionEvaluator for the given point in the PageContext object passed in.

Author:

Shawn Bayern

Field Summary

Fields

Modifier and Type	Field and Description
static String	EVALUATOR_CLASS

Constructor Summary

Constructors

Constructor and Description
ExpressionEvaluatorManager()

Method Summary

Modifier and Type	Method and Description
static Object	coerce(Object value, Class classe) Performs a type conversion according to the EL's rules.
static Object	evaluate(String attributeName, String expression, Class expectedType, javax.servlet.jsp.PageContext pageContext) Invokes the evaluate() method on the "active" ExpressionEvaluator for the given pageContext.
static Object	evaluate(String attributeName, String expression, Class expectedType, javax.servlet.jsp.tagext.Tag tag, javax.servlet.jsp.PageContext pageContext) Invokes the evaluate() method on the "active" ExpressionEvaluator for the given pageContext.
static ExpressionEvaluator	getEvaluatorByName(String name) Deprecated.
static String	validate(String attributeName, String expression) Validates an expression.

Methods inherited from class java.lang.Object

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

Field Detail

EVALUATOR_CLASS

public static final String EVALUATOR_CLASS

See Also:

Constant Field Values

Constructor Detail

ExpressionEvaluatorManager

public ExpressionEvaluatorManager()

Method Detail

evaluate

public static Object evaluate(String attributeName,
                              String expression,
                              Class expectedType,
                              javax.servlet.jsp.tagext.Tag tag,
                              javax.servlet.jsp.PageContext pageContext)
                       throws javax.servlet.jsp.JspException

Invokes the evaluate() method on the "active" ExpressionEvaluator for the given pageContext.

Throws:

javax.servlet.jsp.JspException

evaluate

public static Object evaluate(String attributeName,
                              String expression,
                              Class expectedType,
                              javax.servlet.jsp.PageContext pageContext)
                       throws javax.servlet.jsp.JspException

Invokes the evaluate() method on the "active" ExpressionEvaluator for the given pageContext.

Throws:

javax.servlet.jsp.JspException

getEvaluatorByName

@Deprecated
public static ExpressionEvaluator getEvaluatorByName(String name)
                                                          throws javax.servlet.jsp.JspException

Deprecated.

Gets an ExpressionEvaluator from the cache, or seeds the cache if we haven't seen a particular ExpressionEvaluator before.

Throws:

javax.servlet.jsp.JspException

coerce

public static Object coerce(Object value,
                            Class classe)
                     throws javax.servlet.jsp.JspException

Performs a type conversion according to the EL's rules.

Throws:

javax.servlet.jsp.JspException

validate

public static String validate(String attributeName,
                              String expression)

Validates an expression.

Parameters:

attributeName - the name of the attribute containing the expression

expression - the expression to validate

Returns:

null an error message or null of the expression is valid