com.sun.grizzly.http.jk.util.res.StringManager Maven / Gradle / Ivy
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 * Copyright 2004 The Apache Software Foundation
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 * you may not use this file except in compliance with the License.
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package com.sun.grizzly.http.jk.util.res;
import java.text.MessageFormat;
import java.util.*;
/**
 * An internationalization / localization helper class which reduces
 * the bother of handling ResourceBundles and takes care of the
 * common cases of message formating which otherwise require the
 * creation of Object arrays and such.
 * 
 * The StringManager operates on a package basis. One StringManager
 * per package can be created and accessed via the getManager method
 * call.
 * 
 * The StringManager will look for a ResourceBundle named by
 * the package name given plus the suffix of "LocalStrings". In
 * practice, this means that the localized information will be contained
 * in a LocalStrings.properties file located in the package
 * directory of the classpath.
 * 
 * Please see the documentation for java.util.ResourceBundle for
 * more information.
 *
 * @author James Duncan Davidson [[email protected]]
 * @author James Todd [[email protected]]
 * @author Mel Martinez [[email protected]]
 * @version $Revision: 1.3 $ $Date: 2007/05/05 05:33:17 $
 * @see java.util.ResourceBundle
 */
public class StringManager {
    /**
     * The ResourceBundle for this StringManager.
     */
    private volatile ResourceBundle bundle;
    private String packageName;
    private Locale locale;
    private ClassLoader classLoader;
    /**
     * Creates a new StringManager for a given package. This is a
     * private method and all access to it is arbitrated by the
     * static getManager method call so that only one StringManager
     * per package will be created.
     *
     * @param packageName Name of package to create StringManager for.
     */
    private StringManager(String packageName, ClassLoader loader) {
        this(packageName, Locale.getDefault(), loader);
    }
    private StringManager(String packageName, Locale loc, ClassLoader loader) {
        this.packageName = packageName;
        this.locale = loc;
        this.classLoader = loader;
    }
    private ResourceBundle getResourceBundle() {
        if (bundle != null) return bundle;
        String bundleName = packageName + ".LocalStrings";
        try {
            bundle = ResourceBundle.getBundle(bundleName, locale, classLoader);
        } catch (MissingResourceException ex) {
            bundle = ResourceBundle.getBundle(bundleName, Locale.US, classLoader);
        }
        return bundle;
    }
    private StringManager(ResourceBundle bundle) {
        this.bundle = bundle;
    }
    /**
     * Get a string from the underlying resource bundle or return
     * null if the String is not found.
     *
     * @param key to desired resource String
     * @return resource String matching key from underlying
     *         bundle or null if not found.
     * @throws IllegalArgumentException if key is null.
     */
    public String getString(String key) {
        if (key == null) {
            String msg = "key may not have a null value";
            throw new IllegalArgumentException(msg);
        }
        String str;
        try {
            str = getResourceBundle().getString(key);
        } catch (MissingResourceException mre) {
            //bad: shouldn't mask an exception the following way:
            //   str = "[cannot find message associated with key '" + key + "' due to " + mre + "]";
            //     because it hides the fact that the String was missing
            //     from the calling code.
            //good: could just throw the exception (or wrap it in another)
            //      but that would probably cause much havoc on existing
            //      code.
            //better: consistent with container pattern to
            //      simply return null.  Calling code can then do
            //      a null check.
            str = null;
        }
        return str;
    }
    /**
     * Get a string from the underlying resource bundle and format
     * it with the given set of arguments.
     *
     * @param key
     * @param args
     */
    public String getString(String key, Object[] args) {
        String iString;
        String value = getString(key);
        // this check for the runtime exception is some pre 1.1.6
        // VM's don't do an automatic toString() on the passed in
        // objects and barf out
        try {
            // ensure the arguments are not null so pre 1.2 VM's don't barf
            if (args == null) {
                args = new Object[1];
            }
            Object[] nonNullArgs = args;
            for (int i = 0; i < args.length; i++) {
                if (args[i] == null) {
                    if (nonNullArgs == args) {
                        nonNullArgs = args.clone();
                    }
                    nonNullArgs[i] = "null";
                }
            }
            if (value == null) value = key;
            iString = MessageFormat.format(value, nonNullArgs);
        } catch (IllegalArgumentException iae) {
            StringBuffer buf = new StringBuffer();
            buf.append(value);
            for (int i = 0; i < args.length; i++) {
                buf.append(" arg[").append(i).append("]=").append(args[i]);
            }
            iString = buf.toString();
        }
        return iString;
    }
    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object argument. This argument can of course be
     * a String object.
     *
     * @param key
     * @param arg
     */
    public String getString(String key, Object arg) {
        Object[] args = new Object[]{arg};
        return getString(key, args);
    }
    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     */
    public String getString(String key, Object arg1, Object arg2) {
        Object[] args = new Object[]{arg1, arg2};
        return getString(key, args);
    }
    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     * @param arg3
     */
    public String getString(String key, Object arg1, Object arg2,
                            Object arg3) {
        Object[] args = new Object[]{arg1, arg2, arg3};
        return getString(key, args);
    }
    /**
     * Get a string from the underlying resource bundle and format it
     * with the given object arguments. These arguments can of course
     * be String objects.
     *
     * @param key
     * @param arg1
     * @param arg2
     * @param arg3
     * @param arg4
     */
    public String getString(String key, Object arg1, Object arg2,
                            Object arg3, Object arg4) {
        Object[] args = new Object[]{arg1, arg2, arg3, arg4};
        return getString(key, args);
    }
    // --------------------------------------------------------------
    // STATIC SUPPORT METHODS
    // --------------------------------------------------------------
    private static Hashtable managers =
            new Hashtable();
    /**
     * Get the StringManager for a particular package. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created and returned.
     *
     * @param packageName
     */
    public synchronized static StringManager getManager(String packageName,
                                                        ClassLoader loader) {
        StringManager mgr = managers.get(packageName);
        if (mgr == null) {
            mgr = new StringManager(packageName, loader);
            managers.put(packageName, mgr);
        }
        return mgr;
    }
    /**
     * Get the StringManager for a particular package. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created and returned.
     */
    public synchronized static StringManager getManager(ResourceBundle bundle) {
        return new StringManager(bundle);
    }
    /**
     * Get the StringManager for a particular package and Locale. If a manager for
     * a package already exists, it will be reused, else a new
     * StringManager will be created for that Locale and returned.
     *
     * @param packageName
     */
    public synchronized static StringManager getManager(String packageName,
                                                        Locale loc,
                                                        ClassLoader loader) {
        StringManager mgr = managers.get(packageName + "_" + loc.toString());
        if (mgr == null) {
            mgr = new StringManager(packageName, loc, loader);
            managers.put(packageName + '_' + loc.toString(), mgr);
        }
        return mgr;
    }
}