org.springframework.expression.common

Class LiteralExpression

java.lang.Object

org.springframework.expression.common.LiteralExpression

All Implemented Interfaces:

Expression

public class LiteralExpression
extends Object
implements Expression

A very simple hardcoded implementation of the Expression interface that represents a string literal. It is used with CompositeStringExpression when representing a template expression which is made up of pieces - some being real expressions to be handled by an EL implementation like Spel, and some being just textual elements.

Since:

3.0

Author:

Andy Clement

Constructor Summary

Constructors

Constructor and Description
LiteralExpression(String literalValue)

Method Summary

Methods

Modifier and Type	Method and Description
String	getExpressionString() Returns the original string used to create this expression, unmodified.
String	getValue() Evaluate this expression in the default standard context.
<T> T	getValue(Class<T> expectedResultType) Evaluate the expression in the default context.
String	getValue(EvaluationContext context) Evaluate this expression in the provided context and return the result of evaluation.
<T> T	getValue(EvaluationContext context, Class<T> expectedResultType) Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc - the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type.
String	getValue(EvaluationContext context, Object rootObject) Evaluate this expression in the provided context and return the result of evaluation, but use the supplied root context as an override for any default root object specified in the context.
<T> T	getValue(EvaluationContext context, Object rootObject, Class<T> desiredResultType) Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc - the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type.
String	getValue(Object rootObject) Evaluate this expression against the specified root object
<T> T	getValue(Object rootObject, Class<T> desiredResultType) Evaluate the expression in the default context against the specified root object.
Class	getValueType() Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.
Class	getValueType(EvaluationContext context) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
Class	getValueType(EvaluationContext context, Object rootObject) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
Class	getValueType(Object rootObject) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.
TypeDescriptor	getValueTypeDescriptor() Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.
TypeDescriptor	getValueTypeDescriptor(EvaluationContext context) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
TypeDescriptor	getValueTypeDescriptor(EvaluationContext context, Object rootObject) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
TypeDescriptor	getValueTypeDescriptor(Object rootObject) Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.
boolean	isWritable(EvaluationContext context) Determine if an expression can be written to, i.e.
boolean	isWritable(EvaluationContext context, Object rootObject) Determine if an expression can be written to, i.e.
boolean	isWritable(Object rootObject) Determine if an expression can be written to, i.e.
void	setValue(EvaluationContext context, Object value) Set this expression in the provided context to the value provided.
void	setValue(EvaluationContext context, Object rootObject, Object value) Set this expression in the provided context to the value provided.
void	setValue(Object rootObject, Object value) Set this expression in the provided context to the value provided.

Methods inherited from class java.lang.Object

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

Constructor Detail

LiteralExpression

public LiteralExpression(String literalValue)

Method Detail

getExpressionString

public final String getExpressionString()

Description copied from interface: Expression

Returns the original string used to create this expression, unmodified.

Specified by:

getExpressionString in interface Expression

Returns:

the original expression string

getValue

public String getValue()

Description copied from interface: Expression

Evaluate this expression in the default standard context.

Specified by:

getValue in interface Expression

Returns:

the evaluation result

getValue

public String getValue(EvaluationContext context)

Description copied from interface: Expression

Evaluate this expression in the provided context and return the result of evaluation.

Specified by:

getValue in interface Expression

Parameters:

context - the context in which to evaluate the expression

Returns:

the evaluation result

getValue

public String getValue(Object rootObject)

Description copied from interface: Expression

Evaluate this expression against the specified root object

Specified by:

getValue in interface Expression

Parameters:

rootObject - the root object against which properties/etc will be resolved

Returns:

the evaluation result

getValueType

public Class getValueType(EvaluationContext context)

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.

Specified by:

getValueType in interface Expression

Parameters:

context - the context in which to evaluate the expression

Returns:

the most general type of value that can be set on this context

getValueTypeDescriptor

public TypeDescriptor getValueTypeDescriptor(EvaluationContext context)

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.

Specified by:

getValueTypeDescriptor in interface Expression

Parameters:

context - the context in which to evaluate the expression

Returns:

a type descriptor for the most general type of value that can be set on this context

getValueTypeDescriptor

public TypeDescriptor getValueTypeDescriptor()

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.

Specified by:

getValueTypeDescriptor in interface Expression

Returns:

a type descriptor for the most general type of value that can be set on this context

setValue

public void setValue(EvaluationContext context,
            Object value)
              throws EvaluationException

Description copied from interface: Expression

Set this expression in the provided context to the value provided.

Specified by:

setValue in interface Expression

Parameters:

context - the context in which to set the value of the expression

value - the new value

Throws:

EvaluationException - if there is a problem during evaluation

getValue

public <T> T getValue(EvaluationContext context,
             Class<T> expectedResultType)
           throws EvaluationException

Description copied from interface: Expression

Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc - the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type.

Specified by:

getValue in interface Expression

Parameters:

context - the context in which to evaluate the expression

expectedResultType - the class the caller would like the result to be

Returns:

the evaluation result

Throws:

EvaluationException - if there is a problem during evaluation

getValue

public <T> T getValue(Class<T> expectedResultType)
           throws EvaluationException

Description copied from interface: Expression

Evaluate the expression in the default context. If the result of the evaluation does not match (and cannot be converted to) the expected result type then an exception will be returned.

Specified by:

getValue in interface Expression

Parameters:

expectedResultType - the class the caller would like the result to be

Returns:

the evaluation result

Throws:

EvaluationException - if there is a problem during evaluation

isWritable

public boolean isWritable(EvaluationContext context)

Description copied from interface: Expression

Determine if an expression can be written to, i.e. setValue() can be called.

Specified by:

isWritable in interface Expression

Parameters:

context - the context in which the expression should be checked

Returns:

true if the expression is writable

getValueType

public Class getValueType()

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.

Specified by:

getValueType in interface Expression

Returns:

the most general type of value that can be set on this context

getValue

public <T> T getValue(Object rootObject,
             Class<T> desiredResultType)
           throws EvaluationException

Description copied from interface: Expression

Evaluate the expression in the default context against the specified root object. If the result of the evaluation does not match (and cannot be converted to) the expected result type then an exception will be returned.

Specified by:

getValue in interface Expression

Parameters:

rootObject - the root object against which properties/etc will be resolved

desiredResultType - the class the caller would like the result to be

Returns:

the evaluation result

Throws:

EvaluationException - if there is a problem during evaluation

getValue

public String getValue(EvaluationContext context,
              Object rootObject)
                throws EvaluationException

Description copied from interface: Expression

Evaluate this expression in the provided context and return the result of evaluation, but use the supplied root context as an override for any default root object specified in the context.

Specified by:

getValue in interface Expression

Parameters:

context - the context in which to evaluate the expression

rootObject - the root object against which properties/etc will be resolved

Returns:

the evaluation result

Throws:

EvaluationException - if there is a problem during evaluation

getValue

public <T> T getValue(EvaluationContext context,
             Object rootObject,
             Class<T> desiredResultType)
           throws EvaluationException

Description copied from interface: Expression

Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc - the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type. The supplied root object overrides any default specified on the supplied context.

Specified by:

getValue in interface Expression

Parameters:

context - the context in which to evaluate the expression

rootObject - the root object against which properties/etc will be resolved

desiredResultType - the class the caller would like the result to be

Returns:

the evaluation result

Throws:

EvaluationException - if there is a problem during evaluation

getValueType

public Class getValueType(Object rootObject)
                   throws EvaluationException

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.

Specified by:

getValueType in interface Expression

Parameters:

rootObject - the root object against which to evaluate the expression

Returns:

the most general type of value that can be set on this context

Throws:

EvaluationException - if there is a problem determining the type

getValueType

public Class getValueType(EvaluationContext context,
                 Object rootObject)
                   throws EvaluationException

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context. The supplied root object overrides any specified in the context.

Specified by:

getValueType in interface Expression

Parameters:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

Returns:

the most general type of value that can be set on this context

Throws:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

public TypeDescriptor getValueTypeDescriptor(Object rootObject)
                                      throws EvaluationException

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method using the default context.

Specified by:

getValueTypeDescriptor in interface Expression

Parameters:

rootObject - the root object against which to evaluate the expression

Returns:

a type descriptor for the most general type of value that can be set on this context

Throws:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

public TypeDescriptor getValueTypeDescriptor(EvaluationContext context,
                                    Object rootObject)
                                      throws EvaluationException

Description copied from interface: Expression

Returns the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context. The supplied root object overrides any specified in the context.

Specified by:

getValueTypeDescriptor in interface Expression

Parameters:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

Returns:

a type descriptor for the most general type of value that can be set on this context

Throws:

EvaluationException - if there is a problem determining the type

isWritable

public boolean isWritable(EvaluationContext context,
                 Object rootObject)
                   throws EvaluationException

Description copied from interface: Expression

Determine if an expression can be written to, i.e. setValue() can be called. The supplied root object overrides any specified in the context.

Specified by:

isWritable in interface Expression

Parameters:

context - the context in which the expression should be checked

rootObject - the root object against which to evaluate the expression

Returns:

true if the expression is writable

Throws:

EvaluationException - if there is a problem determining if it is writable

setValue

public void setValue(EvaluationContext context,
            Object rootObject,
            Object value)
              throws EvaluationException

Description copied from interface: Expression

Set this expression in the provided context to the value provided. The supplied root object overrides any specified in the context.

Specified by:

setValue in interface Expression

Parameters:

context - the context in which to set the value of the expression

rootObject - the root object against which to evaluate the expression

value - the new value

Throws:

EvaluationException - if there is a problem during evaluation

isWritable

public boolean isWritable(Object rootObject)
                   throws EvaluationException

Description copied from interface: Expression

Determine if an expression can be written to, i.e. setValue() can be called.

Specified by:

isWritable in interface Expression

Parameters:

rootObject - the root object against which to evaluate the expression

Returns:

true if the expression is writable

Throws:

EvaluationException - if there is a problem determining if it is writable

setValue

public void setValue(Object rootObject,
            Object value)
              throws EvaluationException

Description copied from interface: Expression

Set this expression in the provided context to the value provided.

Specified by:

setValue in interface Expression

Parameters:

rootObject - the root object against which to evaluate the expression

value - the new value

Throws:

EvaluationException - if there is a problem during evaluation