    001    package org.apache.turbine.services.velocity;
    002
    003
    004    /*
    005     * Licensed to the Apache Software Foundation (ASF) under one
    006     * or more contributor license agreements.  See the NOTICE file
    007     * distributed with this work for additional information
    008     * regarding copyright ownership.  The ASF licenses this file
    009     * to you under the Apache License, Version 2.0 (the
    010     * "License"); you may not use this file except in compliance
    011     * with the License.  You may obtain a copy of the License at
    012     *
    013     *   http://www.apache.org/licenses/LICENSE-2.0
    014     *
    015     * Unless required by applicable law or agreed to in writing,
    016     * software distributed under the License is distributed on an
    017     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    018     * KIND, either express or implied.  See the License for the
    019     * specific language governing permissions and limitations
    020     * under the License.
    021     */
    022
    023
    024    import java.io.OutputStream;
    025    import java.io.Writer;
    026
    027    import org.apache.turbine.pipeline.PipelineData;
    028    import org.apache.turbine.services.TurbineServices;
    029    import org.apache.turbine.util.RunData;
    030
    031    import org.apache.velocity.context.Context;
    032
    033    /**
    034     * This is a simple static accessor to common Velocity tasks such as
    035     * getting an instance of a context as well as handling a request for
    036     * processing a template.
    037     * <pre>
    038     * Context context = TurbineVelocity.getContext(data);
    039     * context.put("message", "Hello from Turbine!");
    040     * String results = TurbineVelocity.handleRequest(context, "helloWorld.vm");
    041     * data.getPage().getBody().addElement(results);
    042     * </pre>
    043     *
    044     * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
    045     * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
    046     * @author <a href="mailto:jvanzyl@periapt.com.com">Jason van Zyl</a>
    047     * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    048     * @version $Id: TurbineVelocity.java 615328 2008-01-25 20:25:05Z tv $
    049     */
    050    public abstract class TurbineVelocity
    051    {
    052        /**
    053         * Utility method for accessing the service
    054         * implementation
    055         *
    056         * @return a VelocityService implementation instance
    057         */
    058        public static VelocityService getService()
    059        {
    060            return (VelocityService) TurbineServices
    061                    .getInstance().getService(VelocityService.SERVICE_NAME);
    062        }
    063
    064        /**
    065         * This allows you to pass in a context and a path to a template
    066         * file and then grabs an instance of the velocity service and
    067         * processes the template and returns the results as a String
    068         * object.
    069         *
    070         * @param context A Context.
    071         * @param template The path for the template files.
    072         * @return A String.
    073         * @exception Exception a generic exception.
    074         */
    075        public static String handleRequest(Context context, String template)
    076                throws Exception
    077        {
    078            return getService().handleRequest(context, template);
    079        }
    080
    081        /**
    082         * Process the request and fill in the template with the values
    083         * you set in the Context.
    084         *
    085         * @param context A Context.
    086         * @param template A String with the filename of the template.
    087         * @param out A OutputStream where we will write the process template as
    088         * a String.
    089         * @exception Exception a generic exception.
    090         */
    091        public static void handleRequest(Context context, String template,
    092                                         OutputStream out)
    093                throws Exception
    094        {
    095            getService().handleRequest(context, template, out);
    096        }
    097
    098        /**
    099         * Process the request and fill in the template with the values
    100         * you set in the Context.
    101         *
    102         * @param context A Context.
    103         * @param template A String with the filename of the template.
    104         * @param writer A Writer where we will write the process template as
    105         * a String.
    106         * @exception Exception a generic exception.
    107         */
    108        public static void handleRequest(Context context,
    109                                         String template,
    110                                         Writer writer)
    111                throws Exception
    112        {
    113            getService().handleRequest(context, template, writer);
    114        }
    115
    116        /**
    117         * This returns a Context that you can pass into handleRequest
    118         * once you have populated it with information that the template
    119         * will know about.
    120         * @deprecated Use the PipelineData version instead.
    121         * @param data A Turbine RunData.
    122         * @return A Context.
    123         */
    124        public static Context getContext(RunData data)
    125        {
    126            return getService().getContext(data);
    127        }
    128
    129        /**
    130         * This returns a Context that you can pass into handleRequest
    131         * once you have populated it with information that the template
    132         * will know about.
    133         *
    134         * @param data A Turbine RunData.
    135         * @return A Context.
    136         */
    137        public static Context getContext(PipelineData pipelineData)
    138        {
    139            return getService().getContext(pipelineData);
    140        }
    141
    142        /**
    143         * This method returns a blank Context object, which
    144         * also contains the global context object. Do not use
    145         * this method if you need an empty context object! Use
    146         * getNewContext for this.
    147         *
    148         * @return A WebContext.
    149         */
    150        public static Context getContext()
    151        {
    152            return getService().getContext();
    153        }
    154
    155        /**
    156         * This method returns a new, empty Context object.
    157         *
    158         * @return A WebContext.
    159         */
    160        public static Context getNewContext()
    161        {
    162            return getService().getNewContext();
    163        }
    164
    165        /**
    166         * Performs post-request actions (releases context
    167         * tools back to the object pool).
    168         *
    169         * @param context a Velocity Context
    170         */
    171        public static void requestFinished(Context context)
    172        {
    173            getService().requestFinished(context);
    174        }
    175    }