org.springframework.binding.expression.support

Class NullParserContext

java.lang.Object

org.springframework.binding.expression.support.NullParserContext

All Implemented Interfaces:

ParserContext

public final class NullParserContext
extends java.lang.Object
implements ParserContext

A null object implementation of ParserContext. Mainly used internally by expression parser implementations when null is passed in as a parser context value.

Author:

Keith Donad

Field Summary

Fields

Modifier and Type	Field and Description
static ParserContext	INSTANCE The null parser context object instance; a singleton.

Method Summary

Modifier and Type	Method and Description
java.lang.Class<?>	getEvaluationContextType() Returns the type of context object the parsed expression will evaluate in.
java.lang.Class<?>	getExpectedEvaluationResultType() Returns the expected type of object returned from evaluating the parsed expression.
ExpressionVariable[]	getExpressionVariables() Returns additional expression variables or aliases that can be referenced during expression evaluation.
boolean	isTemplate() Whether or not the expression being parsed is a template.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final ParserContext INSTANCE

The null parser context object instance; a singleton.

Method Detail

getEvaluationContextType

public java.lang.Class<?> getEvaluationContextType()

Description copied from interface: ParserContext

Returns the type of context object the parsed expression will evaluate in. An expression parser may use this value to install custom variable resolves for that particular type of context.

Specified by:

getEvaluationContextType in interface ParserContext

Returns:

the evaluation context type

getExpectedEvaluationResultType

public java.lang.Class<?> getExpectedEvaluationResultType()

Description copied from interface: ParserContext

Returns the expected type of object returned from evaluating the parsed expression. An expression parser may use this value to coerce an raw evaluation result before it is returned.

Specified by:

getExpectedEvaluationResultType in interface ParserContext

Returns:

the expected evaluation result type

getExpressionVariables

public ExpressionVariable[] getExpressionVariables()

Description copied from interface: ParserContext

Returns additional expression variables or aliases that can be referenced during expression evaluation. An expression parser will register these variables for reference during evaluation.

Specified by:

getExpressionVariables in interface ParserContext

isTemplate

public boolean isTemplate()

Description copied from interface: ParserContext

Whether or not the expression being parsed is a template. A template expression consists of literal text that can be mixed with evaluatable blocks. Some examples:

           Some literal text
     Hello #{name.firstName}!
     #{3 + 4}
 

Specified by:

isTemplate in interface ParserContext

Returns:

true if the expression is a template, false otherwise