javax.el

Class ResourceBundleELResolver

java.lang.Object

javax.el.ELResolver

javax.el.ResourceBundleELResolver

public class ResourceBundleELResolver
extends ELResolver

Defines property resolution behavior on instances of java.util.ResourceBundle. This resolver handles base objects of type java.util.ResourceBundle. It accepts any object as a property and coerces it to a java.lang.String for invoking java.util.ResourceBundle.getObject(String). This resolver is read only and will throw a PropertyNotWritableException if setValue is called. ELResolvers are combined together using CompositeELResolvers, to define rich semantics for evaluating an expression. See the javadocs for ELResolver for details.

Field Summary

Fields inherited from class javax.el.ELResolver

RESOLVABLE_AT_DESIGN_TIME, TYPE

Constructor Summary

Constructors

Constructor and Description
ResourceBundleELResolver()

Method Summary

Methods

Modifier and Type	Method and Description
Class<?>	getCommonPropertyType(ELContext context, Object base) If the base object is a ResourceBundle, returns the most general type that this resolver accepts for the property argument.
Iterator<FeatureDescriptor>	getFeatureDescriptors(ELContext context, Object base) If the base object is a ResourceBundle, returns an Iterator containing the set of keys available in the ResourceBundle.
Class<?>	getType(ELContext context, Object base, Object property) If the base object is an instance of ResourceBundle, return null, since the resolver is read only.
Object	getValue(ELContext context, Object base, Object property) If the base object is an instance of ResourceBundle, the provided property will first be coerced to a String.
boolean	isReadOnly(ELContext context, Object base, Object property) If the base object is not null and an instanceof java.util.ResourceBundle, return true.
void	setValue(ELContext context, Object base, Object property, Object value) If the base object is a ResourceBundle, throw a PropertyNotWritableException.

Methods inherited from class javax.el.ELResolver

invoke

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceBundleELResolver

public ResourceBundleELResolver()

Method Detail

getCommonPropertyType

public Class<?> getCommonPropertyType(ELContext context,
                             Object base)

If the base object is a ResourceBundle, returns the most general type that this resolver accepts for the property argument. Otherwise, returns null. Assuming the base is a ResourceBundle, this method will always return String.class.

Specified by:

getCommonPropertyType in class ELResolver

Parameters:

context - The context of this evaluation.

base - The bundle to analyze. Only bases of type ResourceBundle are handled by this resolver.

Returns:

null if base is not a ResourceBundle; otherwise String.class.

getFeatureDescriptors

public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context,
                                                Object base)

If the base object is a ResourceBundle, returns an Iterator containing the set of keys available in the ResourceBundle. Otherwise, returns null. The Iterator returned must contain zero or more instances of java.beans.FeatureDescriptor. Each info object contains information about a key in the ResourceBundle, and is initialized as follows:

• displayName - The String key name
• name - Same as displayName property
• shortDescription - Empty string
• expert - false
• hidden - false
• preferred - true

In addition, the following named attributes must be set in the returned FeatureDescriptors:

• ELResolver.TYPE - String.class.
• ELResolver.RESOLVABLE_AT_DESIGN_TIME - true

Specified by:

getFeatureDescriptors in class ELResolver

Parameters:

context - The context of this evaluation.

base - The bundle to analyze. Only bases of type ResourceBundle are handled by this resolver.

Returns:

An Iterator containing zero or more (possibly infinitely more) FeatureDescriptor objects, each representing a key in this bundle, or null if the base object is not a ResourceBundle.

getType

public Class<?> getType(ELContext context,
               Object base,
               Object property)

If the base object is an instance of ResourceBundle, return null, since the resolver is read only. If the base is ResourceBundle, the propertyResolved property of the ELContext object must be set to true by this resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value.

Specified by:

getType in class ELResolver

Parameters:

context - The context of this evaluation.

base - The bundle to analyze. Only bases of type ResourceBundle are handled by this resolver.

property - The name of the property to analyze.

Returns:

If the propertyResolved property of ELContext was set to true, then null; otherwise undefined.

Throws:

NullPointerException - if context is null

getValue

public Object getValue(ELContext context,
              Object base,
              Object property)

If the base object is an instance of ResourceBundle, the provided property will first be coerced to a String. The Object returned by getObject on the base ResourceBundle will be returned. If the base is ResourceBundle, the propertyResolved property of the ELContext object must be set to true by this resolver, before returning. If this property is not true after this method is called, the caller should ignore the return value.

Specified by:

getValue in class ELResolver

Parameters:

context - The context of this evaluation.

base - The bundle to analyze. Only bases of type ResourceBundle are handled by this resolver.

property - The name of the property to analyze. Will be coerced to a String.

Returns:

If the propertyResolved property of ELContext was set to true, then null if property is null; otherwise the Object for the given key (property coerced to String) from the ResourceBundle. If no object for the given key can be found, then the String "???" + key + "???".

Throws:

NullPointerException - if context is null.

ELException - if an exception was thrown while performing the property or variable resolution. The thrown exception must be included as the cause property of this exception, if available.

isReadOnly

public boolean isReadOnly(ELContext context,
                 Object base,
                 Object property)

If the base object is not null and an instanceof java.util.ResourceBundle, return true.

Specified by:

isReadOnly in class ELResolver

Parameters:

context - The context of this evaluation.

base - The base object whose property value is to be analyzed, or null to analyze a top-level variable.

property - The property or variable to return the read-only status for.

Returns:

If the propertyResolved property of ELContext was set to true, then true; otherwise undefined.

Throws:

NullPointerException - if context is null.

setValue

public void setValue(ELContext context,
            Object base,
            Object property,
            Object value)

If the base object is a ResourceBundle, throw a PropertyNotWritableException.

Specified by:

setValue in class ELResolver

Parameters:

context - The context of this evaluation.

base - The bundle to analyze. Only bases of type ResourceBundle are handled by this resolver.

property - The name of the property to analyze. Will be coerced to a String.

value - The value to be set.

Throws:

NullPointerException - if context is null.

PropertyNotWritableException - Always thrown if base is an instance of ResourceBundle.