messagefactory.java

java指南

/*
 * Copyright (c) 2004 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2004 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */


package util;

import java.io.FileInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.util.Locale;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.MissingResourceException;
import javax.faces.FacesException;
import javax.faces.application.Application;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import java.text.MessageFormat;
import java.io.IOException;


/**
 *
 * <p>supported filters: <code>package</code> and
 * <code>protection</code>.</p>
 */
public class MessageFactory extends Object {
    //
    // Protected Constants
    //
    //
    // Class Variables
    //
    //
    // Instance Variables
    //
    // Attribute Instance Variables
    // Relationship Instance Variables
    //
    // Constructors and Initializers    
    //
    private MessageFactory() {
    }

    //
    // Class methods
    //
    //
    // General Methods
    //
    public static String substituteParams(Locale locale, String msgtext,
        Object[] params) {
        String localizedStr = null;

        if ((params == null) || (msgtext == null)) {
            return msgtext;
        }

        StringBuffer b = new StringBuffer(100);
        MessageFormat mf = new MessageFormat(msgtext);

        if (locale != null) {
            mf.setLocale(locale);
            b.append(mf.format(params));
            localizedStr = b.toString();
        }

        return localizedStr;
    }

    /**
     * This version of getMessage() is used in the RI for localizing RI
     * specific messages.
     */
    public static FacesMessage getMessage(String messageId, Object[] params) {
        Locale locale = null;
        FacesContext context = FacesContext.getCurrentInstance();

        // context.getViewRoot() may not have been initialized at this point.
        if ((context != null) && (context.getViewRoot() != null)) {
            locale = context.getViewRoot()
                            .getLocale();

            if (locale == null) {
                locale = Locale.getDefault();
            }
        } else {
            locale = Locale.getDefault();
        }

        return getMessage(locale, messageId, params);
    }

    public static FacesMessage getMessage(Locale locale, String messageId,
        Object[] params) {
        FacesMessage result = null;
        String summary = null;
        String detail = null;
        String bundleName = null;
        ResourceBundle bundle = null;

        // see if we have a user-provided bundle
        if (null != (bundleName = getApplication()
                                          .getMessageBundle())) {
            if (null != (bundle =
                        ResourceBundle.getBundle(bundleName, locale,
                            getCurrentLoader(bundleName)))) {
                // see if we have a hit
                try {
                    summary = bundle.getString(messageId);
                } catch (MissingResourceException e) {
                }
            }
        }

        // we couldn't find a summary in the user-provided bundle
        if (null == summary) {
            // see if we have a summary in the app provided bundle
            bundle =
                ResourceBundle.getBundle(FacesMessage.FACES_MESSAGES, locale,
                    getCurrentLoader(bundleName));

            if (null == bundle) {
                throw new NullPointerException();
            }

            // see if we have a hit
            try {
                summary = bundle.getString(messageId);
            } catch (MissingResourceException e) {
            }
        }

        // we couldn't find a summary anywhere!  Return null
        if (null == summary) {
            return null;
        }

        // At this point, we have a summary and a bundle.
        if ((null == summary) || (null == bundle)) {
            throw new NullPointerException();
        }

        summary = substituteParams(locale, summary, params);

        try {
            detail =
                substituteParams(locale,
                    bundle.getString(messageId + "_detail"), params);
        } catch (MissingResourceException e) {
        }

        return (new FacesMessage(summary, detail));
    }

    //
    // Methods from MessageFactory
    // 
    public static FacesMessage getMessage(FacesContext context, String messageId) {
        return getMessage(context, messageId, null);
    }

    public static FacesMessage getMessage(FacesContext context,
        String messageId, Object[] params) {
        if ((context == null) || (messageId == null)) {
            throw new NullPointerException(
                "One or more parameters could be null");
        }

        Locale locale = null;

        // viewRoot may not have been initialized at this point.
        if ((context != null) && (context.getViewRoot() != null)) {
            locale = context.getViewRoot()
                            .getLocale();
        } else {
            locale = Locale.getDefault();
        }

        if (null == locale) {
            throw new NullPointerException();
        }

        FacesMessage message = getMessage(locale, messageId, params);

        if (message != null) {
            return message;
        }

        locale = Locale.getDefault();

        return (getMessage(locale, messageId, params));
    }

    public static FacesMessage getMessage(FacesContext context,
        String messageId, Object param0) {
        return getMessage(context, messageId, new Object[] { param0 });
    }

    public static FacesMessage getMessage(FacesContext context,
        String messageId, Object param0, Object param1) {
        return getMessage(context, messageId, new Object[] { param0, param1 });
    }

    public static FacesMessage getMessage(FacesContext context,
        String messageId, Object param0, Object param1, Object param2) {
        return getMessage(context, messageId,
            new Object[] { param0, param1, param2 });
    }

    public static FacesMessage getMessage(FacesContext context,
        String messageId, Object param0, Object param1, Object param2,
        Object param3) {
        return getMessage(context, messageId,
            new Object[] { param0, param1, param2, param3 });
    }

    protected static Application getApplication() {
        return (FacesContext.getCurrentInstance().getApplication());
    }

    protected static ClassLoader getCurrentLoader(Object fallbackClass) {
        ClassLoader loader = Thread.currentThread()
                                   .getContextClassLoader();

        if (loader == null) {
            loader = fallbackClass.getClass()
                                  .getClassLoader();
        }

        return loader;
    }
}
 // end of class MessageFactory