messagetag.java

structs源码

/*
 * $Id: MessageTag.java 471754 2006-11-06 14:55:09Z husted $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.struts.taglib.bean;

import org.apache.struts.Globals;
import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import java.util.Locale;

/**
 * Custom tag that retrieves an internationalized messages string (with
 * optional parametric replacement) from the <code>ActionResources</code>
 * object stored as a context attribute by our associated
 * <code>ActionServlet</code> implementation.
 *
 * @version $Rev: 471754 $ $Date: 2005-09-16 09:38:33 -0400 (Fri, 16 Sep 2005)
 *          $
 */
public class MessageTag extends TagSupport {
    /**
     * The message resources for this package.
     */
    protected static MessageResources messages =
        MessageResources.getMessageResources(
            "org.apache.struts.taglib.bean.LocalStrings");

    // ------------------------------------------------------------- Properties

    /**
     * The first optional argument.
     */
    protected String arg0 = null;

    /**
     * The second optional argument.
     */
    protected String arg1 = null;

    /**
     * The third optional argument.
     */
    protected String arg2 = null;

    /**
     * The fourth optional argument.
     */
    protected String arg3 = null;

    /**
     * The fifth optional argument.
     */
    protected String arg4 = null;

    /**
     * The servlet context attribute key for our resources.
     */
    protected String bundle = null;

    /**
     * The message key of the message to be retrieved.
     */
    protected String key = null;

    /**
     * Name of the bean that contains the message key.
     */
    protected String name = null;

    /**
     * Name of the property to be accessed on the specified bean.
     */
    protected String property = null;

    /**
     * The scope to be searched to retrieve the specified bean.
     */
    protected String scope = null;

    /**
     * The session scope key under which our Locale is stored.
     */
    protected String localeKey = Globals.LOCALE_KEY;

    public String getArg0() {
        return (this.arg0);
    }

    public void setArg0(String arg0) {
        this.arg0 = arg0;
    }

    public String getArg1() {
        return (this.arg1);
    }

    public void setArg1(String arg1) {
        this.arg1 = arg1;
    }

    public String getArg2() {
        return (this.arg2);
    }

    public void setArg2(String arg2) {
        this.arg2 = arg2;
    }

    public String getArg3() {
        return (this.arg3);
    }

    public void setArg3(String arg3) {
        this.arg3 = arg3;
    }

    public String getArg4() {
        return (this.arg4);
    }

    public void setArg4(String arg4) {
        this.arg4 = arg4;
    }

    public String getBundle() {
        return (this.bundle);
    }

    public void setBundle(String bundle) {
        this.bundle = bundle;
    }

    public String getKey() {
        return (this.key);
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getProperty() {
        return (this.property);
    }

    public void setProperty(String property) {
        this.property = property;
    }

    public String getScope() {
        return (this.scope);
    }

    public void setScope(String scope) {
        this.scope = scope;
    }

    public String getLocale() {
        return (this.localeKey);
    }

    public void setLocale(String localeKey) {
        this.localeKey = localeKey;
    }

    // --------------------------------------------------------- Public Methods

    /**
     * Process the start tag.
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {
        String key = this.key;

        if (key == null) {
            // Look up the requested property value
            Object value =
                TagUtils.getInstance().lookup(pageContext, name, property, scope);

            if ((value != null) && !(value instanceof String)) {
                JspException e =
                    new JspException(messages.getMessage("message.property", key));

                TagUtils.getInstance().saveException(pageContext, e);
                throw e;
            }

            key = (String) value;
        }

        // Construct the optional arguments array we will be using
        Object[] args = new Object[] { arg0, arg1, arg2, arg3, arg4 };

        // Retrieve the message string we are looking for
        String message =
            TagUtils.getInstance().message(pageContext, this.bundle,
                this.localeKey, key, args);

        if (message == null) {
            Locale locale =
                TagUtils.getInstance().getUserLocale(pageContext, this.localeKey);
            String localeVal =
                (locale == null) ? "default locale" : locale.toString();
            JspException e =
                new JspException(messages.getMessage("message.message",
                        "\"" + key + "\"",
                        "\"" + ((bundle == null) ? "(default bundle)" : bundle)
                        + "\"", localeVal));

            TagUtils.getInstance().saveException(pageContext, e);
            throw e;
        }

        TagUtils.getInstance().write(pageContext, message);

        return (SKIP_BODY);
    }

    /**
     * Release any acquired resources.
     */
    public void release() {
        super.release();
        arg0 = null;
        arg1 = null;
        arg2 = null;
        arg3 = null;
        arg4 = null;
        bundle = Globals.MESSAGES_KEY;
        key = null;
        name = null;
        property = null;
        scope = null;
        localeKey = Globals.LOCALE_KEY;
    }
}