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/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * glassfish/bootstrap/legal/CDDLv1.0.txt or
 * https://glassfish.dev.java.net/public/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * glassfish/bootstrap/legal/CDDLv1.0.txt.  If applicable,
 * add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your
 * own identifying information: Portions Copyright [yyyy]
 * [name of copyright owner]
 *
 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
 */
package javax.el;

import java.beans.FeatureDescriptor;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

/**
 * Defines property resolution behavior on instances of
 * {@link 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 * {@link java.util.ResourceBundle#getObject(java.lang.String)}. *

* *

* This resolver is read only and will throw a * {@link PropertyNotWritableException} if setValue is called. *

* *

* ELResolvers are combined together using * {@link CompositeELResolver}s, to define rich semantics for evaluating an * expression. See the javadocs for {@link ELResolver} for details. *

* * @see CompositeELResolver * @see ELResolver * @see java.util.ResourceBundle * @since JSP 2.1 */ public class ResourceBundleELResolver extends ELResolver { /** * 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. *

* @param context * The context of this evaluation. * @param base * The ResourceBundle to analyze. * @param property * The name of the property to analyze. Will be coerced to a * String. * @return 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 * @throws 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. */ public Object getValue(ELContext context, Object base, Object property) { if (context == null) { throw new NullPointerException(); } if (base instanceof ResourceBundle) { context.setPropertyResolved(true); if (property != null) { try { return ((ResourceBundle) base).getObject(property .toString()); } catch (MissingResourceException e) { return "???" + property + "???"; } } } return null; } /** * 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. *

* * @param context * The context of this evaluation. * @param base * The ResourceBundle to analyze. * @param property * The name of the property to analyze. * @return If the propertyResolved property of * ELContext was set to true, then * null; otherwise undefined. * @throws NullPointerException * if context is null */ public Class getType(ELContext context, Object base, Object property) { if (context == null) { throw new NullPointerException(); } if (base instanceof ResourceBundle) { context.setPropertyResolved(true); } return null; } /** * If the base object is a ResourceBundle, throw a * {@link PropertyNotWritableException}. * * @param context * The context of this evaluation. * @param base * The ResourceBundle to be modified. Only bases that are of type * ResourceBundle are handled. * @param property * The String property to use. * @param value * The value to be set. * @throws NullPointerException * if context is null. * @throws PropertyNotWritableException * Always thrown if base is an instance of ReasourceBundle. */ public void setValue(ELContext context, Object base, Object property, Object value) { if (context == null) { throw new NullPointerException(); } if (base instanceof ResourceBundle) { context.setPropertyResolved(true); throw new PropertyNotWritableException( "ResourceBundles are immutable"); } } /** * If the base object is not null and an instanceof {@link ResourceBundle}, * return true. * * @param context * The context of this evaluation. * @param base * The ResourceBundle to be modified. Only bases that are of type * ResourceBundle are handled. * @param property * The String property to use. * @return If the propertyResolved property of * ELContext was set to true, then * true; otherwise undefined. * @throws NullPointerException * if context is null */ public boolean isReadOnly(ELContext context, Object base, Object property) { if (context == null) { throw new NullPointerException(); } if (base instanceof ResourceBundle) { context.setPropertyResolved(true); return true; } return false; } /** * 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 {@link java.beans.FeatureDescriptor}. Each info object contains * information about a key in the ResourceBundle, and is initialized as * follows: *

*
  • displayName - The String key *
  • 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: *
    *
  • {@link ELResolver#TYPE} - String.class
  • *
  • {@link ELResolver#RESOLVABLE_AT_DESIGN_TIME} - true
  • *
    *

    * * @param context * The context of this evaluation. * @param base * The bundle whose keys are to be iterated over. Only bases of * type ResourceBundle are handled by this * resolver. * @return 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. */ public Iterator getFeatureDescriptors(ELContext context, Object base) { if (base instanceof ResourceBundle) { ResourceBundle bundle = (ResourceBundle) base; List features = new ArrayList(); String key = null; FeatureDescriptor desc = null; for (Enumeration e = bundle.getKeys(); e.hasMoreElements();) { key = (String) e.nextElement(); desc = new FeatureDescriptor(); desc.setDisplayName(key); desc.setExpert(false); desc.setHidden(false); desc.setName(key); desc.setPreferred(true); desc.setValue(TYPE, String.class); desc.setValue(RESOLVABLE_AT_DESIGN_TIME, Boolean.TRUE); features.add(desc); } return features.iterator(); } return null; } /** * 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. * * @param context * The context of this evaluation. * @param base * The bundle to analyze. Only bases of type * ResourceBundle are handled by this resolver. * @return null if base is not a ResourceBundle; * otherwise String.class. */ public Class getCommonPropertyType(ELContext context, Object base) { if (base instanceof ResourceBundle) { return String.class; } return null; } }





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