resources.java

MVC开源框架

/*
 * $Id: Resources.java 476419 2006-11-18 02:28:07Z niallp $
 *
 * 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.validator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.validator.Arg;
import org.apache.commons.validator.Field;
import org.apache.commons.validator.Msg;
import org.apache.commons.validator.Validator;
import org.apache.commons.validator.ValidatorAction;
import org.apache.commons.validator.ValidatorResources;
import org.apache.commons.validator.Var;
import org.apache.struts.Globals;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.ModuleUtils;
import org.apache.struts.util.RequestUtils;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import java.util.Locale;

/**
 * This class helps provides some useful methods for retrieving objects from
 * different scopes of the application.
 *
 * @version $Rev: 476419 $ $Date: 2005-09-16 23:34:41 -0400 (Fri, 16 Sep 2005)
 *          $
 * @since Struts 1.1
 */
public class Resources {
    /**
     * The message resources for this package.
     */
    private static MessageResources sysmsgs =
        MessageResources.getMessageResources(
            "org.apache.struts.validator.LocalStrings");

    /**
     * <p>Commons Logging instance.</p>
     */
    private static Log log = LogFactory.getLog(Resources.class);

    /**
     * Resources key the <code>ServletContext</code> is stored under.
     */
    private static String SERVLET_CONTEXT_PARAM =
        "javax.servlet.ServletContext";

    /**
     * Resources key the <code>HttpServletRequest</code> is stored under.
     */
    private static String HTTP_SERVLET_REQUEST_PARAM =
        "javax.servlet.http.HttpServletRequest";

    /**
     * Resources key the <code>ActionMessages</code> is stored under.
     */
    private static String ACTION_MESSAGES_PARAM =
        "org.apache.struts.action.ActionMessages";

    /**
     * Retrieve <code>ValidatorResources</code> for the current module.
     *
     * @param application Application Context
     * @param request     The ServletRequest
     */
    public static ValidatorResources getValidatorResources(
        ServletContext application, HttpServletRequest request) {
        String prefix =
            ModuleUtils.getInstance().getModuleConfig(request, application)
                       .getPrefix();

        return (ValidatorResources) application.getAttribute(ValidatorPlugIn.VALIDATOR_KEY
            + prefix);
    }

    /**
     * Retrieve <code>MessageResources</code> for the module.
     *
     * @param request the servlet request
     */
    public static MessageResources getMessageResources(
        HttpServletRequest request) {
        return (MessageResources) request.getAttribute(Globals.MESSAGES_KEY);
    }

    /**
     * Retrieve <code>MessageResources</code> for the module and bundle.
     *
     * @param application the servlet context
     * @param request     the servlet request
     * @param bundle      the bundle key
     */
    public static MessageResources getMessageResources(
        ServletContext application, HttpServletRequest request, String bundle) {
        if (bundle == null) {
            bundle = Globals.MESSAGES_KEY;
        }

        MessageResources resources =
            (MessageResources) request.getAttribute(bundle);

        if (resources == null) {
            ModuleConfig moduleConfig =
                ModuleUtils.getInstance().getModuleConfig(request, application);

            resources =
                (MessageResources) application.getAttribute(bundle
                    + moduleConfig.getPrefix());
        }

        if (resources == null) {
            resources = (MessageResources) application.getAttribute(bundle);
        }

        if (resources == null) {
            throw new NullPointerException(
                "No message resources found for bundle: " + bundle);
        }

        return resources;
    }

    /**
     * Get the value of a variable.
     *
     * @param varName   The variable name
     * @param field     the validator Field
     * @param validator The Validator
     * @param request   the servlet request
     * @param required  Whether the variable is mandatory
     * @return The variable's value
     */
    public static String getVarValue(String varName, Field field,
        Validator validator, HttpServletRequest request, boolean required) {
        Var var = field.getVar(varName);

        if (var == null) {
            String msg = sysmsgs.getMessage("variable.missing", varName);

            if (required) {
                throw new IllegalArgumentException(msg);
            }

            if (log.isDebugEnabled()) {
                log.debug(field.getProperty() + ": " + msg);
            }

            return null;
        }

        ServletContext application =
            (ServletContext) validator.getParameterValue(SERVLET_CONTEXT_PARAM);

        return getVarValue(var, application, request, required);
    }

    /**
     * Get the value of a variable.
     *
     * @param var         the validator variable
     * @param application The ServletContext
     * @param request     the servlet request
     * @param required    Whether the variable is mandatory
     * @return The variables values
     */
    public static String getVarValue(Var var, ServletContext application,
        HttpServletRequest request, boolean required) {
        String varName = var.getName();
        String varValue = var.getValue();

        // Non-resource variable
        if (!var.isResource()) {
            return varValue;
        }

        // Get the message resources
        String bundle = var.getBundle();
        MessageResources messages =
            getMessageResources(application, request, bundle);

        // Retrieve variable's value from message resources
        Locale locale = RequestUtils.getUserLocale(request, null);
        String value = messages.getMessage(locale, varValue, null);

        // Not found in message resources
        if ((value == null) && required) {
            throw new IllegalArgumentException(sysmsgs.getMessage(
                    "variable.resource.notfound", varName, varValue, bundle));
        }

        if (log.isDebugEnabled()) {
            log.debug("Var=[" + varName + "], " + "bundle=[" + bundle + "], "
                + "key=[" + varValue + "], " + "value=[" + value + "]");
        }

        return value;
    }

    /**
     * Gets the <code>Locale</code> sensitive value based on the key passed
     * in.
     *
     * @param messages The Message resources
     * @param locale   The locale.
     * @param key      Key used to lookup the message
     */
    public static String getMessage(MessageResources messages, Locale locale,
        String key) {
        String message = null;

        if (messages != null) {
            message = messages.getMessage(locale, key);
        }

        return (message == null) ? "" : message;
    }

    /**
     * Gets the <code>Locale</code> sensitive value based on the key passed
     * in.
     *
     * @param request servlet request
     * @param key     the request key
     */
    public static String getMessage(HttpServletRequest request, String key) {
        MessageResources messages = getMessageResources(request);

        return getMessage(messages, RequestUtils.getUserLocale(request, null),
            key);
    }

    /**
     * Gets the locale sensitive message based on the <code>ValidatorAction</code>
     * message and the <code>Field</code>'s arg objects.
     *
     * @param messages The Message resources
     * @param locale   The locale