localizedtextutil.java

来自「在Struts2中的jar包xwork的源代码.版本为2.0.7」· Java 代码 · 共 806 行 · 第 1/3 页

/*
 * Copyright (c) 2002-2006 by OpenSymphony
 * All rights reserved.
 */
package com.opensymphony.xwork2.util;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ModelDriven;

import ognl.OgnlRuntime;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.text.MessageFormat;
import java.util.*;


/**
 * Provides support for localization in XWork.
 *
 * <!-- START SNIPPET: searchorder -->
 * Resource bundles are searched in the following order:<p/>
 * <p/>
 * <ol>
 * <li>ActionClass.properties</li>
 * <li>BaseClass.properties (all the way to Object.properties)</li>
 * <li>Interface.properties (every interface and sub-interface)</li>
 * <li>ModelDriven's model (if implements ModelDriven), for the model object repeat from 1</li>
 * <li>package.properties (of the directory where class is located and every parent directory all the way to the root directory)</li>
 * <li>search up the i18n message key hierarchy itself</li>
 * <li>global resource properties</li>
 * </ol>
 * <p/>
 * <!-- END SNIPPET: searchorder -->
 *
 * <!-- START SNIPPET: packagenote -->
 * To clarify #5, while traversing the package hierarchy, WW will look for a file package.properties:<p/>
 * com/<br/>
 * &nbsp; acme/<br/>
 * &nbsp; &nbsp; package.properties<br/>
 * &nbsp; &nbsp; actions/<br/>
 * &nbsp; &nbsp; &nbsp; package.properties<br/>
 * &nbsp; &nbsp; &nbsp; FooAction.java<br/>
 * &nbsp; &nbsp; &nbsp; FooAction.properties<br/>
 * <p/>
 * If FooAction.properties does not exist, com/acme/action/package.properties will be searched for, if
 * not found com/acme/package.properties, if not found com/package.properties, etc.
 * <p/>
 * <!-- END SNIPPET: packagenote -->
 *
 * <!-- START SNIPPET: globalresource -->
 * A global resource bundle could be specified programatically, as well as the locale.
 * <p/>
 * <!-- END SNIPPET: globalresource -->
 *
 * @author Jason Carreira
 * @author Mark Woon
 * @author Rainer Hermanns
 * @author tm_jee
 * 
 * @version $Date: 2007-09-03 05:36:45 +0200 (Mon, 03 Sep 2007) $ $Id: LocalizedTextUtil.java 1590 2007-09-03 03:36:45Z mrdon $
 */
public class LocalizedTextUtil {
	
	private static final Log _log = LogFactory.getLog(LocalizedTextUtil.class);

    private static List DEFAULT_RESOURCE_BUNDLES = null;
    private static final Log LOG = LogFactory.getLog(LocalizedTextUtil.class);
    private static boolean reloadBundles = false;
    private static final Map<String, String> misses = new HashMap<String, String>();
    private static final Map messageFormats = new HashMap();

    static {
        clearDefaultResourceBundles();
    }


    /**
     * Clears the internal list of resource bundles.
     */
    public static void clearDefaultResourceBundles() {
    	if (DEFAULT_RESOURCE_BUNDLES != null) {
    		DEFAULT_RESOURCE_BUNDLES.clear();
    	}
        DEFAULT_RESOURCE_BUNDLES = Collections.synchronizedList(new ArrayList());
        DEFAULT_RESOURCE_BUNDLES.add("com/opensymphony/xwork2/xwork-messages");
    }

    /**
     * Should resorce bundles be reloaded.
     * @param reloadBundles  reload bundles?  
     */
    public static void setReloadBundles(boolean reloadBundles) {
        LocalizedTextUtil.reloadBundles = reloadBundles;
    }

    /**
     * Add's the bundle to the internal list of default bundles.
     * <p/>
     * If the bundle already exists in the list it will be readded.
     * 
     * @param resourceBundleName   the name of the bundle to add.
     */
    public static void addDefaultResourceBundle(String resourceBundleName) {
        //make sure this doesn't get added more than once
        DEFAULT_RESOURCE_BUNDLES.remove(resourceBundleName);
        DEFAULT_RESOURCE_BUNDLES.add(0, resourceBundleName);

        if (LOG.isDebugEnabled()) {
            LOG.debug("Added default resource bundle '" + resourceBundleName + "' to default resource bundles = " + DEFAULT_RESOURCE_BUNDLES);
        }
    }

    /**
     * Builds a {@link java.util.Locale} from a String of the form en_US_foo into a Locale
     * with language "en", country "US" and variant "foo". This will parse the output of
     * {@link java.util.Locale#toString()}.
     *
     * @param localeStr The locale String to parse.
     * @param defaultLocale The locale to use if localeStr is <tt>null</tt>.
     * @return requested Locale
     */
    public static Locale localeFromString(String localeStr, Locale defaultLocale) {
        if ((localeStr == null) || (localeStr.trim().length() == 0) || (localeStr.equals("_"))) {
            if ( defaultLocale != null) {
                return defaultLocale;
            }
            return Locale.getDefault();
        }

        int index = localeStr.indexOf('_');
        if (index < 0) {
            return new Locale(localeStr);
        }

        String language = localeStr.substring(0, index);
        if (index == localeStr.length()) {
            return new Locale(language);
        }

        localeStr = localeStr.substring(index + 1);
        index = localeStr.indexOf('_');
        if (index < 0) {
            return new Locale(language, localeStr);
        }

        String country = localeStr.substring(0, index);
        if (index == localeStr.length()) {
            return new Locale(language, country);
        }

        localeStr = localeStr.substring(index + 1);
        return new Locale(language, country, localeStr);
    }

    /**
     * Returns a localized message for the specified key, aTextName.  Neither the key nor the
     * message is evaluated.
     *
     * @param aTextName the message key
     * @param locale    the locale the message should be for
     * @return a localized message based on the specified key, or null if no localized message can be found for it
     */
    public static String findDefaultText(String aTextName, Locale locale) {
        List localList = DEFAULT_RESOURCE_BUNDLES; // it isn't sync'd, but this is so rare, let's do it anyway

        for (Iterator iterator = localList.iterator(); iterator.hasNext();) {
            String bundleName = (String) iterator.next();

            ResourceBundle bundle = findResourceBundle(bundleName, locale);
            if (bundle != null) {
                reloadBundles();
                try {
                    return bundle.getString(aTextName);
                } catch (MissingResourceException e) {
                    // ignore and try others
                }
            }
        }

        return null;
    }

    /**
     * Returns a localized message for the specified key, aTextName, substituting variables from the
     * array of params into the message.  Neither the key nor the message is evaluated.
     *
     * @param aTextName the message key
     * @param locale    the locale the message should be for
     * @param params    an array of objects to be substituted into the message text
     * @return A formatted message based on the specified key, or null if no localized message can be found for it
     */
    public static String findDefaultText(String aTextName, Locale locale, Object[] params) {
        String defaultText = findDefaultText(aTextName, locale);
        if (defaultText != null) {
            MessageFormat mf = buildMessageFormat(defaultText, locale);
            return mf.format(params);
        }
        return null;
    }

    /**
     * Finds the given resorce bundle by it's name.
     * <p/>
     * Will use <code>Thread.currentThread().getContextClassLoader()</code> as the classloader.
     * 
     * @param aBundleName  the name of the bundle (usually it's FQN classname).
     * @param locale       the locale.
     * @return  the bundle, <tt>null</tt> if not found.
     */
    public static ResourceBundle findResourceBundle(String aBundleName, Locale locale) {
        synchronized (misses) {
            String key = createMissesKey(aBundleName, locale);
            try {
                if (!misses.containsKey(key)) {
                    return ResourceBundle.getBundle(aBundleName, locale, Thread.currentThread().getContextClassLoader());
                }
            } catch (MissingResourceException ex) {
                misses.put(key, aBundleName);
            }
        }

        return null;
    }

    /**
     * Creates a key to used for lookup/storing in the bundle misses cache.
     *
     * @param aBundleName  the name of the bundle (usually it's FQN classname).
     * @param locale       the locale.
     * @return the key to use for lookup/storing in the bundle misses cache.
     */
    private static String createMissesKey(String aBundleName, Locale locale) {
        return aBundleName + "_" + locale.toString();
    }

    /**
     * Calls {@link #findText(Class aClass, String aTextName, Locale locale, String defaultMessage, Object[] args)}
     * with aTextName as the default message.
     *
     * @see #findText(Class aClass, String aTextName, Locale locale, String defaultMessage, Object[] args)
     */
    public static String findText(Class aClass, String aTextName, Locale locale) {
        return findText(aClass, aTextName, locale, aTextName, new Object[0]);
    }

    /**
     * Finds a localized text message for the given key, aTextName. Both the key and the message
     * itself is evaluated as required.  The following algorithm is used to find the requested
     * message:
     * <p/>
     * <ol>
     * <li>Look for message in aClass' class hierarchy.
     * <ol>
     * <li>Look for the message in a resource bundle for aClass</li>
     * <li>If not found, look for the message in a resource bundle for any implemented interface</li>
     * <li>If not found, traverse up the Class' hierarchy and repeat from the first sub-step</li>
     * </ol></li>
     * <li>If not found and aClass is a {@link ModelDriven} Action, then look for message in
     * the model's class hierarchy (repeat sub-steps listed above).</li>
     * <li>If not found, look for message in child property.  This is determined by evaluating
     * the message key as an OGNL expression.  For example, if the key is
     * <i>user.address.state</i>, then it will attempt to see if "user" can be resolved into an