javax.servlet.jsp.jstl.core
Class IndexedValueExpression

java.lang.Object
  javax.el.Expression
      javax.el.ValueExpression
          javax.servlet.jsp.jstl.core.IndexedValueExpression

All Implemented Interfaces:

Serializable

public final class IndexedValueExpression
extends ValueExpression

Version:

$Id: IndexedValueExpression.java,v 1.2 2005/12/08 01:20:43 kchung Exp $

Author:

Jacob Hookom

See Also:

Serialized Form

Field Summary

protected Integer	i
protected ValueExpression	orig

Constructor Summary

IndexedValueExpression(ValueExpression orig, int i)

Method Summary

boolean	equals(Object obj) Determines whether the specified object is equal to this Expression.
Class	getExpectedType() Returns the type the result of the expression will be coerced to after evaluation.
String	getExpressionString() Returns the original String used to create this Expression, unmodified.
Class	getType(ELContext context) Evaluates the expression relative to the provided context, and returns the most general type that is acceptable for an object to be passed as the value parameter in a future call to the ValueExpression.setValue(javax.el.ELContext, java.lang.Object) method.
Object	getValue(ELContext context) Evaluates the expression relative to the provided context, and returns the resulting value.
int	hashCode() Returns the hash code for this Expression.
boolean	isLiteralText() Returns whether this expression was created from only literal text.
boolean	isReadOnly(ELContext context) Evaluates the expression relative to the provided context, and returns true if a call to ValueExpression.setValue(javax.el.ELContext, java.lang.Object) will always fail.
void	setValue(ELContext context, Object value) Evaluates the expression relative to the provided context, and sets the result to the provided value.

Methods inherited from class java.lang.Object

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

Field Detail

i

protected final Integer i

orig

protected final ValueExpression orig

Constructor Detail

IndexedValueExpression

public IndexedValueExpression(ValueExpression orig,
                              int i)

Method Detail

getValue

public Object getValue(ELContext context)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and returns the resulting value.

The resulting value is automatically coerced to the type returned by getExpectedType(), which was provided to the ExpressionFactory when this expression was created.

Specified by:

getValue in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

The result of the expression evaluation.

setValue

public void setValue(ELContext context,
                     Object value)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and sets the result to the provided value.

Specified by:

setValue in class ValueExpression

Parameters:

context - The context of this evaluation.

value - The new value to be set.

isReadOnly

public boolean isReadOnly(ELContext context)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and returns true if a call to ValueExpression.setValue(javax.el.ELContext, java.lang.Object) will always fail.

Specified by:

isReadOnly in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

true if the expression is read-only or false if not.

getType

public Class getType(ELContext context)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and returns the most general type that is acceptable for an object to be passed as the value parameter in a future call to the ValueExpression.setValue(javax.el.ELContext, java.lang.Object) method.

This is not always the same as getValue().getClass(). For example, in the case of an expression that references an array element, the getType method will return the element type of the array, which might be a superclass of the type of the actual element that is currently in the specified array element.

Specified by:

getType in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

the most general acceptable type; otherwise undefined.

getExpectedType

public Class getExpectedType()

Description copied from class: ValueExpression

Returns the type the result of the expression will be coerced to after evaluation.

Specified by:

getExpectedType in class ValueExpression

Returns:

the expectedType passed to the ExpressionFactory.createValueExpression method that created this ValueExpression.

getExpressionString

public String getExpressionString()

Description copied from class: Expression

Returns the original String used to create this Expression, unmodified.

This is used for debugging purposes but also for the purposes of comparison (e.g. to ensure the expression in a configuration file has not changed).

This method does not provide sufficient information to re-create an expression. Two different expressions can have exactly the same expression string but different function mappings. Serialization should be used to save and restore the state of an Expression.

Specified by:

getExpressionString in class Expression

Returns:

The original expression String.

equals

public boolean equals(Object obj)

Description copied from class: Expression

Determines whether the specified object is equal to this Expression.

The result is true if and only if the argument is not null, is an Expression object that is the of the same type (ValueExpression or MethodExpression), and has an identical parsed representation.

Note that two expressions can be equal if their expression Strings are different. For example, ${fn1:foo()} and ${fn2:foo()} are equal if their corresponding FunctionMappers mapped fn1:foo and fn2:foo to the same method.

Specified by:

equals in class Expression

Parameters:

obj - the Object to test for equality.

Returns:

true if obj equals this Expression; false otherwise.

See Also:

Hashtable, Object.equals(java.lang.Object)

hashCode

public int hashCode()

Description copied from class: Expression

Returns the hash code for this Expression.

See the note in the Expression.equals(java.lang.Object) method on how two expressions can be equal if their expression Strings are different. Recall that if two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. Implementations must take special note and implement hashCode correctly.

Specified by:

hashCode in class Expression

Returns:

The hash code for this Expression.

See Also:

Expression.equals(java.lang.Object), Hashtable, Object.hashCode()

isLiteralText

public boolean isLiteralText()

Description copied from class: Expression

Returns whether this expression was created from only literal text.

This method must return true if and only if the expression string this expression was created from contained no unescaped EL delimeters (${...} or #{...}).

Specified by:

isLiteralText in class Expression

Returns:

true if this expression was created from only literal text; false otherwise.