core/src/main/java/org/apache/struts2/components/I18n.java

/*
 * 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.struts2.components;

import java.io.Writer;
import java.util.ResourceBundle;

import com.opensymphony.xwork2.LocaleProviderFactory;
import com.opensymphony.xwork2.LocalizedTextProvider;
import com.opensymphony.xwork2.TextProviderFactory;
import org.apache.struts2.views.annotations.StrutsTag;
import org.apache.struts2.views.annotations.StrutsTagAttribute;
import org.apache.struts2.StrutsException;

import com.opensymphony.xwork2.LocaleProvider;
import com.opensymphony.xwork2.TextProvider;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.ValueStack;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * <!-- START SNIPPET: javadoc -->
 *
 * Gets a resource bundle and place it on the value stack. This allows
 * the text tag to access messages from any bundle, and not just the bundle
 * associated with the current action.
 *
 * <!-- END SNIPPET: javadoc -->
 *
 * <!-- START SNIPPET: params-->
 *
 * <ul>
 *      <li>name* - the resource bundle's name (eg foo/bar/customBundle)</li>
 * </ul>
 *
 * <!-- END SNIPPET: params -->
 *
 * <p>
 * Example:
 * </p>
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 *
 * &lt;s:i18n name="myCustomBundle"&gt;
 *    The i18n value for key aaa.bbb.ccc in myCustomBundle is &lt;s:property value="text('aaa.bbb.ccc')" /&gt;
 * &lt;/s:i18n&gt;
 *
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 *
 * <pre>
 * <!-- START SNIPPET: i18nExample -->
 *
 * &lt;s:i18n name="some.package.bundle" &gt;
 *      &lt;s:text name="some.key" /&gt;
 * &lt;/s:i18n&gt;
 *
 * <!-- END SNIPPET: i18nExample -->
 * </pre>
 *
 */
@StrutsTag(name="i18n", tldTagClass="org.apache.struts2.views.jsp.I18nTag", description="Get a resource bundle" +
                " and place it on the value stack")
public class I18n extends Component {

    private static final Logger LOG = LogManager.getLogger(I18n.class);

    protected boolean pushed;
    protected String name;

    private LocalizedTextProvider localizedTextProvider;
    private TextProvider textProvider;
    private TextProvider defaultTextProvider;
    private LocaleProviderFactory localeProviderFactory;
    private TextProviderFactory textProviderFactory;

    public I18n(ValueStack stack) {
        super(stack);
    }

    @Inject
    public void setLocalizedTextProvider(LocalizedTextProvider localizedTextProvider) {
        this.localizedTextProvider = localizedTextProvider;
    }

    @Inject("system")
    public void setTextProvider(TextProvider textProvider) {
        this.defaultTextProvider = textProvider;
    }

    @Inject
    public void setTextProviderFactory(TextProviderFactory textProviderFactory) {
        this.textProviderFactory = textProviderFactory;
    }

    @Inject
    public void setLocaleProviderFactory(LocaleProviderFactory localeProviderFactory) {
        this.localeProviderFactory = localeProviderFactory;
    }

    public boolean start(Writer writer) {
        boolean result = super.start(writer);

        try {
            String name = this.findString(this.name, "name", "Resource bundle name is required. Example: foo or foo_en");
            ResourceBundle bundle = defaultTextProvider.getTexts(name);

            if (bundle == null) {
                LocaleProvider localeProvider = localeProviderFactory.createLocaleProvider();
                bundle = localizedTextProvider.findResourceBundle(name, localeProvider.getLocale());
            }

            if (bundle != null) {
                textProvider = textProviderFactory.createInstance(bundle);
                getStack().push(textProvider);
                pushed = true;
            }
        } catch (Exception e) {
            throw new StrutsException("Could not find the bundle " + name, e);
        }

        return result;
    }

    public boolean end(Writer writer, String body) throws StrutsException {
        if (pushed) {
            Object o = getStack().pop();
            if ((o == null) || (!o.equals(textProvider))) {
                LOG.error("A closing i18n tag attempted to pop its own TextProvider from the top of the ValueStack but popped an unexpected object ("+(o != null ? o.getClass() : "null")+"). " +
                            "Refactor the page within the i18n tags to ensure no objects are pushed onto the ValueStack without popping them prior to the closing tag. " +
                            "If you see this message it's likely that the i18n's TextProvider is still on the stack and will continue to provide message resources after the closing tag.");
                throw new StrutsException("A closing i18n tag attempted to pop its TextProvider from the top of the ValueStack but popped an unexpected object ("+(o != null ? o.getClass() : "null")+")");
            }
        }

        return super.end(writer, body);
    }

    @StrutsTagAttribute(description="Name of resource bundle to use (eg foo/bar/customBundle)", required=true, defaultValue="String")
    public void setName(String name) {
        this.name = name;
    }
}