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package org.hsqldb.resources;

import java.lang.reflect.Method;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import org.hsqldb.lib.HashMap;
import org.hsqldb.lib.HsqlArrayList;

A ResourceBundle helper class. 

Allows clients to get/set locale and get at localized resource bundle
content in a resource path independent manner, without having to worry
about handling exception states or deal directly with ResourceBundle
object instances. Instead, clients receive numeric handles to the
underlying objects.  Rather than causing exception states, missing or
inaccessible resources and underlying MissingResource and NullPointer
exceptions result in null return values when attempting to retrieve a
resource. 

Author:
Campbell Burnet (campbell-burnet@users dot sourceforge.net)
Version:
1.7.2
Since:
1.7.2/**
 * A ResourceBundle helper class. <p>
 *
 * Allows clients to get/set locale and get at localized resource bundle
 * content in a resource path independent manner, without having to worry
 * about handling exception states or deal directly with ResourceBundle
 * object instances. Instead, clients receive numeric handles to the
 * underlying objects.  Rather than causing exception states, missing or
 * inaccessible resources and underlying MissingResource and NullPointer
 * exceptions result in null return values when attempting to retrieve a
 * resource. <p>
 *
 * @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
 * @version 1.7.2
 * @since 1.7.2
 */
public final class ResourceBundleHandler {

    
Used to synchronize access /** Used to synchronize access */
    private static final Object mutex = new Object();

    
The Locale used internally to fetch resource bundles. /** The Locale used internally to fetch resource bundles. */
    private static Locale locale = Locale.getDefault();

    
Map:  Integer object handle => ResourceBundle object. /** Map:  Integer object handle => <code>ResourceBundle</code> object. */
    private static HashMap bundleHandleMap = new HashMap();

    
List whose elements are ResourceBundle objects /** List whose elements are <code>ResourceBundle</code> objects */
    private static HsqlArrayList bundleList = new HsqlArrayList();

    
The resource path prefix of the ResourceBundle objects
handled by this class.
/**
     * The resource path prefix of the <code>ResourceBundle</code> objects
     * handled by this class.
     */
    private static final String prefix = "org.hsqldb.resources.";

    
JDK 1.1 compliance /** JDK 1.1 compliance */
    private static final Method newGetBundleMethod = getNewGetBundleMethod();

    
Pure utility class: external construction disabled. /** Pure utility class: external construction disabled. */
    private ResourceBundleHandler() {}

    
Getter for property locale. 

Returns:
Value of property locale./**
     * Getter for property locale. <p>
     *
     * @return Value of property locale.
     */
    public static Locale getLocale() {

        synchronized (mutex) {
            return locale;
        }
    }

    
Setter for property locale. 

Params:
l – the new locale
Throws:
IllegalArgumentException – when the new locale is null/**
     * Setter for property locale. <p>
     *
     * @param l the new locale
     * @throws IllegalArgumentException when the new locale is null
     */
    public static void setLocale(Locale l) throws IllegalArgumentException {

        synchronized (mutex) {
            if (l == null) {
                throw new IllegalArgumentException("null locale");
            }

            locale = l;
        }
    }

    
Retrieves an int handle to the ResourceBundle
object corresponding to the specified name and current
Locale, using the specified ClassLoader. 

Params:
cl – The ClassLoader to use in the search
name – of the desired bundle
Returns:
int handle to the ResourceBundle
       object corresponding to the specified name and
       current Locale, or -1 if no such bundle
       can be found/**
     * Retrieves an <code>int</code> handle to the <code>ResourceBundle</code>
     * object corresponding to the specified name and current
     * <code>Locale</code>, using the specified <code>ClassLoader</code>. <p>
     *
     * @return <code>int</code> handle to the <code>ResourceBundle</code>
     *        object corresponding to the specified name and
     *        current <code>Locale</code>, or -1 if no such bundle
     *        can be found
     * @param cl The ClassLoader to use in the search
     * @param name of the desired bundle
     */
    public static int getBundleHandle(String name, ClassLoader cl) {

        Integer        bundleHandle;
        ResourceBundle bundle;
        String         bundleName;
        String         bundleKey;

        bundleName = prefix + name;

        synchronized (mutex) {
            bundleKey    = locale.toString() + bundleName;
            bundleHandle = (Integer) bundleHandleMap.get(bundleKey);

            if (bundleHandle == null) {
                bundle = getBundle(bundleName, locale, cl);

                bundleList.add(bundle);

                bundleHandle = Integer.valueOf(bundleList.size() - 1);

                bundleHandleMap.put(bundleKey, bundleHandle);
            }
        }

        return bundleHandle.intValue();
    }

    
Retrieves, from the ResourceBundle object corresponding
to the specified handle, the String value corresponding
to the specified key.  null is retrieved if either there
 is no ResourceBundle object for the handle or there is no
String value for the specified key. 

Params:
handle – an int handle to a
     ResourceBundle object
key – A String key to a String value
Returns:
The String value corresponding to the specified handle and key./**
     * Retrieves, from the <code>ResourceBundle</code> object corresponding
     * to the specified handle, the <code>String</code> value corresponding
     * to the specified key.  <code>null</code> is retrieved if either there
     *  is no <code>ResourceBundle</code> object for the handle or there is no
     * <code>String</code> value for the specified key. <p>
     *
     * @param handle an <code>int</code> handle to a
     *      <code>ResourceBundle</code> object
     * @param key A <code>String</code> key to a <code>String</code> value
     * @return The String value corresponding to the specified handle and key.
     */
    public static String getString(int handle, String key) {

        ResourceBundle bundle;
        String         s;

        synchronized (mutex) {
            if (handle < 0 || handle >= bundleList.size() || key == null) {
                bundle = null;
            } else {
                bundle = (ResourceBundle) bundleList.get(handle);
            }
        }

        if (bundle == null) {
            s = null;
        } else {
            try {
                s = bundle.getString(key);
            } catch (Exception e) {
                s = null;
            }
        }

        return s;
    }

    
One-shot initialization of JDK 1.2+ ResourceBundle.getBundle() method
having ClassLoader in the signature.
/**
     * One-shot initialization of JDK 1.2+ ResourceBundle.getBundle() method
     * having ClassLoader in the signature.
     */
    private static Method getNewGetBundleMethod() {

        Class   clazz;
        Class[] args;

        clazz = ResourceBundle.class;
        args  = new Class[] {
            String.class, Locale.class, ClassLoader.class
        };

        try {
            return clazz.getMethod("getBundle", args);
        } catch (Exception e) {
            return null;
        }
    }

    
Retrieves a resource bundle using the specified base name, locale, and
class loader. This is a JDK 1.1 compliant substitution for the
ResourceBundle method with the same name and signature. If there
is a problem using the JDK 1.2 functionality (the class loader is
specified non-null and the underlying method is not available or there
is a security exception, etc.), then the behaviour reverts to that
of JDK 1.1.
Params:
name – the base name of the resource bundle, a fully
     qualified class name
locale – the locale for which a resource bundle is desired
cl – the class loader from which to load the resource bundle/**
     * Retrieves a resource bundle using the specified base name, locale, and
     * class loader. This is a JDK 1.1 compliant substitution for the
     * ResourceBundle method with the same name and signature. If there
     * is a problem using the JDK 1.2 functionality (the class loader is
     * specified non-null and the underlying method is not available or there
     * is a security exception, etc.), then the behaviour reverts to that
     * of JDK 1.1.
     *
     * @param name the base name of the resource bundle, a fully
     *      qualified class name
     * @param locale the locale for which a resource bundle is desired
     * @param cl the class loader from which to load the resource bundle
     */
    public static ResourceBundle getBundle(String name, Locale locale,
                                           ClassLoader cl)
                                           throws NullPointerException,
                                               MissingResourceException {

        if (cl == null) {
            return ResourceBundle.getBundle(name, locale);
        } else if (newGetBundleMethod == null) {
            return ResourceBundle.getBundle(name, locale);
        } else {
            try {
                return (ResourceBundle) newGetBundleMethod.invoke(null,
                        new Object[] {
                    name, locale, cl
                });
            } catch (Exception e) {
                return ResourceBundle.getBundle(name, locale);
            }
        }
    }
}