001package org.apache.turbine.modules;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import java.lang.reflect.InvocationTargetException;
023import java.lang.reflect.Method;
024import java.util.Arrays;
025
026import org.apache.commons.collections.map.MultiKeyMap;
027import org.apache.commons.lang.StringUtils;
028import org.apache.commons.logging.Log;
029import org.apache.commons.logging.LogFactory;
030import org.apache.fulcrum.parser.ParameterParser;
031import org.apache.fulcrum.parser.ValueParser.URLCaseFolding;
032import org.apache.turbine.Turbine;
033import org.apache.turbine.TurbineConstants;
034import org.apache.turbine.annotation.TurbineActionEvent;
035import org.apache.turbine.pipeline.PipelineData;
036
037/**
038 * <p>
039 *
040 * This is an alternative to the Action class that allows you to do
041 * event based actions. Essentially, you label all your submit buttons
042 * with the prefix of "eventSubmit_" and the suffix of "methodName".
043 * For example, "eventSubmit_doDelete". Then any class that subclasses
044 * this class will get its "doDelete(PipelineData data)" method executed.
045 * If for any reason, it was not able to execute the method, it will
046 * fall back to executing the doPerform() method which is required to
047 * be implemented.
048 *
049 * <p>
050 *
051 * Limitations:
052 *
053 * <p>
054 *
055 * Because ParameterParser makes all the key values lowercase, we have
056 * to do some work to format the string into a method name. For
057 * example, a button name eventSubmit_doDelete gets converted into
058 * eventsubmit_dodelete. Thus, we need to form some sort of naming
059 * convention so that dodelete can be turned into doDelete.
060 *
061 * <p>
062 *
063 * Thus, the convention is this:
064 *
065 * <ul>
066 * <li>The variable name MUST have the prefix "eventSubmit_".</li>
067 * <li>The variable name after the prefix MUST begin with the letters
068 * "do".</li>
069 * <li>The first letter after the "do" will be capitalized and the
070 * rest will be lowercase</li>
071 * </ul>
072 *
073 * If you follow these conventions, then you should be ok with your
074 * method naming in your Action class.
075 *
076 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens </a>
077 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
078 * @author <a href="quintonm@bellsouth.net">Quinton McCombs</a>
079 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
080 * @version $Id: ActionEvent.java 1706425 2015-10-02 14:47:51Z tv $
081 */
082public abstract class ActionEvent extends Action
083{
084        /** Logging */
085        protected Log log = LogFactory.getLog(this.getClass());
086
087        /** The name of the button to look for. */
088        protected static final String BUTTON = "eventSubmit_";
089        /** The length of the button to look for. */
090        protected static final int BUTTON_LENGTH = BUTTON.length();
091    /** The default method. */
092    protected static final String DEFAULT_METHOD = "doPerform";
093        /** The prefix of the method name. */
094        protected static final String METHOD_NAME_PREFIX = "do";
095        /** The length of the method name. */
096        protected static final int METHOD_NAME_LENGTH = METHOD_NAME_PREFIX.length();
097        /** The length of the button to look for. */
098        protected static final int LENGTH = BUTTON.length();
099
100        /**
101         * If true, the eventSubmit_do<xxx> variable must contain
102         * a not null value to be executed.
103         */
104        private boolean submitValueKey = false;
105
106        /**
107         * If true, then exceptions raised in eventSubmit_do<xxx> methods
108         * as well as in doPerform methods are bubbled up to the Turbine
109         * servlet's handleException method.
110         */
111        protected boolean bubbleUpException = true;
112
113        /**
114         * Cache for the methods to invoke
115         */
116        private MultiKeyMap/* <String, Method> */ methodCache = new MultiKeyMap/* <String, Method> */();
117
118        /**
119         * C'tor
120         */
121        public ActionEvent()
122        {
123                super();
124
125                submitValueKey = Turbine.getConfiguration()
126                                .getBoolean(TurbineConstants.ACTION_EVENTSUBMIT_NEEDSVALUE_KEY,
127                                                TurbineConstants.ACTION_EVENTSUBMIT_NEEDSVALUE_DEFAULT);
128                bubbleUpException = Turbine.getConfiguration()
129                                .getBoolean(TurbineConstants.ACTION_EVENT_BUBBLE_EXCEPTION_UP,
130                                                TurbineConstants.ACTION_EVENT_BUBBLE_EXCEPTION_UP_DEFAULT);
131
132                if (log.isDebugEnabled())
133                {
134                log.debug(submitValueKey
135                                ? "ActionEvent accepts only eventSubmit_do Keys with a value != 0"
136                                : "ActionEvent accepts all eventSubmit_do Keys");
137                log.debug(bubbleUpException
138                                  ? "ActionEvent will bubble exceptions up to Turbine.handleException() method"
139                                  : "ActionEvent will not bubble exceptions up.");
140                }
141        }
142
143        /**
144         * Retrieve a method of the given name and signature. The value is cached.
145         *
146         * @param name the name of the method
147         * @param signature an array of classes forming the signature of the method
148         * @param pp ParameterParser for correct folding
149         *
150         * @return the method object
151         * @throws NoSuchMethodException if the method does not exist
152         */
153        protected Method getMethod(String name, Class<?>[] signature, ParameterParser pp) throws NoSuchMethodException
154        {
155            Method method = (Method) this.methodCache.get(name, signature);
156
157            if (method == null)
158            {
159                // Try annotations of public methods
160                Method[] methods = getClass().getMethods();
161                for (Method m : methods)
162                {
163                    if (m.isAnnotationPresent(TurbineActionEvent.class))
164                    {
165                        TurbineActionEvent tae = m.getAnnotation(TurbineActionEvent.class);
166                        if (name.equals(pp.convert(tae.value()))
167                        && Arrays.equals(signature, m.getParameterTypes()))
168                        {
169                            method = m;
170                            break;
171                        }
172                    }
173                }
174
175                // Try legacy mode
176                if (method == null)
177                {
178                String tmp = name.toLowerCase().substring(METHOD_NAME_LENGTH);
179                    method = getClass().getMethod(METHOD_NAME_PREFIX + StringUtils.capitalize(tmp), signature);
180                }
181
182                this.methodCache.put(name, signature, method);
183            }
184
185            return method;
186        }
187
188        /**
189         * This overrides the default Action.doPerform() to execute the
190         * doEvent() method. If that fails, then it will execute the
191         * doPerform() method instead.
192         *
193         * @param pipelineData Turbine information.
194         * @exception Exception a generic exception.
195         */
196        @Override
197    public void doPerform(PipelineData pipelineData)
198                        throws Exception
199        {
200            ParameterParser pp = pipelineData.get(Turbine.class, ParameterParser.class);
201                executeEvents(pp, new Class<?>[]{ PipelineData.class }, new Object[]{ pipelineData });
202        }
203
204        /**
205         * This method should be called to execute the event based system.
206         *
207         * @param pp the parameter parser
208         * @param signature the signature of the method to call
209         * @param parameters the parameters for the method to call
210         *
211         * @exception Exception a generic exception.
212         */
213        protected void executeEvents(ParameterParser pp, Class<?>[] signature, Object[] parameters)
214                        throws Exception
215        {
216                // Name of the button.
217                String theButton = null;
218
219                String button = pp.convert(BUTTON);
220                String key = null;
221
222                // Loop through and find the button.
223                for (String k : pp)
224                {
225                        key = k;
226                        if (key.startsWith(button))
227                        {
228                                if (considerKey(key, pp))
229                                {
230                                        theButton = key;
231                                        break;
232                                }
233                        }
234                }
235
236                if (theButton == null)
237                {
238                    theButton = BUTTON + DEFAULT_METHOD;
239                    key = null;
240                }
241
242                theButton = formatString(theButton, pp);
243                Method method = null;
244
245        try
246        {
247            method = getMethod(theButton, signature, pp);
248        }
249        catch (NoSuchMethodException e)
250        {
251            method = getMethod(DEFAULT_METHOD, signature, pp);
252        }
253        finally
254        {
255            if (key != null)
256            {
257                pp.remove(key);
258            }
259        }
260
261                try
262                {
263                        if (log.isDebugEnabled())
264                        {
265                                log.debug("Invoking " + method);
266                        }
267
268                        method.invoke(this, parameters);
269                }
270                catch (InvocationTargetException ite)
271                {
272                        Throwable t = ite.getTargetException();
273                        if (bubbleUpException)
274                        {
275                if (t instanceof Exception)
276                {
277                    throw (Exception) t;
278                }
279                else
280                {
281                    throw ite;
282                }
283                        }
284                        else
285                        {
286                            log.error("Invokation of " + method , t);
287                        }
288                }
289        }
290
291        /**
292         * This method does the conversion of the lowercase method name
293         * into the proper case.
294         *
295         * @param input The unconverted method name.
296         * @param pp The parameter parser (for correct folding)
297         * @return A string with the method name in the proper case.
298         */
299        protected String formatString(String input, ParameterParser pp)
300        {
301                String tmp = input;
302
303                if (StringUtils.isNotEmpty(input))
304                {
305                        tmp = input.toLowerCase();
306
307                        // Chop off suffixes (for image type)
308                        String methodName = (tmp.endsWith(".x") || tmp.endsWith(".y"))
309                                        ? input.substring(0, input.length() - 2)
310                                        : input;
311
312                        if (pp.getUrlFolding() == URLCaseFolding.NONE)
313                        {
314                tmp = methodName.substring(BUTTON_LENGTH);
315                        }
316                        else
317                        {
318                tmp = methodName.toLowerCase().substring(BUTTON_LENGTH);
319                        }
320                }
321
322                return tmp;
323        }
324
325        /**
326         * Checks whether the selected key really is a valid event.
327         *
328         * @param key The selected key
329         * @param pp The parameter parser to look for the key value
330         *
331         * @return true if this key is really an ActionEvent Key
332         */
333        protected boolean considerKey(String key, ParameterParser pp)
334        {
335                if (!submitValueKey)
336                {
337                        log.debug("No Value required, accepting " + key);
338                        return true;
339                }
340                else
341                {
342                        // If the action.eventsubmit.needsvalue key is true,
343                        // events with a "0" or empty value are ignored.
344                        // This can be used if you have multiple eventSubmit_do<xxx>
345                        // fields in your form which are selected by client side code,
346                        // e.g. JavaScript.
347                        //
348                        // If this key is unset or missing, nothing changes for the
349                        // current behavior.
350                        //
351                        String keyValue = pp.getString(key);
352                        log.debug("Key Value is " + keyValue);
353                        if (StringUtils.isEmpty(keyValue))
354                        {
355                                log.debug("Key is empty, rejecting " + key);
356                                return false;
357                        }
358
359                        try
360                        {
361                                if (Integer.parseInt(keyValue) != 0)
362                                {
363                                        log.debug("Integer != 0, accepting " + key);
364                                        return true;
365                                }
366                        }
367                        catch (NumberFormatException nfe)
368                        {
369                                // Not a number. So it might be a
370                                // normal Key like "continue" or "exit". Accept
371                                // it.
372                                log.debug("Not a number, accepting " + key);
373                                return true;
374                        }
375                }
376                log.debug("Rejecting " + key);
377                return false;
378        }
379}