Package org.apache.turbine.modules

Source Code of org.apache.turbine.modules.ActionEvent

package org.apache.turbine.modules;

/*
* 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.
*/

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Iterator;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.fulcrum.parser.ParameterParser;
import org.apache.fulcrum.parser.ParserService;
import org.apache.turbine.Turbine;
import org.apache.turbine.TurbineConstants;
import org.apache.turbine.pipeline.PipelineData;
import org.apache.turbine.util.RunData;

/**
* <p>
*
* This is an alternative to the Action class that allows you to do
* event based actions. Essentially, you label all your submit buttons
* with the prefix of "eventSubmit_" and the suffix of "methodName".
* For example, "eventSubmit_doDelete". Then any class that subclasses
* this class will get its "doDelete(RunData data)" method executed.
* If for any reason, it was not able to execute the method, it will
* fall back to executing the doPeform() method which is required to
* be implemented.
*
* <p>
*
* Limitations:
*
* <p>
*
* Because ParameterParser makes all the key values lowercase, we have
* to do some work to format the string into a method name. For
* example, a button name eventSubmit_doDelete gets converted into
* eventsubmit_dodelete. Thus, we need to form some sort of naming
* convention so that dodelete can be turned into doDelete.
*
* <p>
*
* Thus, the convention is this:
*
* <ul>
* <li>The variable name MUST have the prefix "eventSubmit_".</li>
* <li>The variable name after the prefix MUST begin with the letters
* "do".</li>
* <li>The first letter after the "do" will be capitalized and the
* rest will be lowercase</li>
* </ul>
*
* If you follow these conventions, then you should be ok with your
* method naming in your Action class.
*
* @author <a href="mailto:jon@latchkey.com">Jon S. Stevens </a>
* @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
* @author <a href="quintonm@bellsouth.net">Quinton McCombs</a>
* @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
* @version $Id: ActionEvent.java 1078552 2011-03-06 19:58:46Z tv $
*/
public abstract class ActionEvent extends Action
{
  /** Logging */
  protected Log log = LogFactory.getLog(this.getClass());

  /** Constant needed for Reflection */
  private static final Class [] methodParams
      = new Class [] { RunData.class };

  /**
   * You need to implement this in your classes that extend this class.
   * @deprecated use PipelineData version instead.
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  @Deprecated
    @Override
    public abstract void doPerform(RunData data)
      throws Exception;

  /**
   * You need to implement this in your classes that extend this class.
   * This should revert to being abstract when RunData has gone.
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  @Override
    public void doPerform(PipelineData pipelineData)
      throws Exception
  {
        RunData data = getRunData(pipelineData);
        doPerform(data);
  }


  /** The name of the button to look for. */
  protected static final String BUTTON = "eventSubmit_";
  /** The length of the button to look for. */
  protected static final int BUTTON_LENGTH = BUTTON.length();
  /** The prefix of the method name. */
  protected static final String METHOD_NAME_PREFIX = "do";
  /** The length of the method name. */
  protected static final int METHOD_NAME_LENGTH = METHOD_NAME_PREFIX.length();
  /** The length of the button to look for. */
  protected static final int LENGTH = BUTTON.length();

  /**
   * If true, the eventSubmit_do<xxx> variable must contain
   * a not null value to be executed.
   */
  private boolean submitValueKey = false;

  /**
   * If true, then exceptions raised in eventSubmit_do<xxx> methods
   * as well as in doPerform methods are bubbled up to the Turbine
   * servlet's handleException method.
   */
  protected boolean bubbleUpException = true;
  /**
   * C'tor
   */
  public ActionEvent()
  {
    super();

    submitValueKey = Turbine.getConfiguration()
        .getBoolean(TurbineConstants.ACTION_EVENTSUBMIT_NEEDSVALUE_KEY,
            TurbineConstants.ACTION_EVENTSUBMIT_NEEDSVALUE_DEFAULT);
    bubbleUpException = Turbine.getConfiguration()
        .getBoolean(TurbineConstants.ACTION_EVENT_BUBBLE_EXCEPTION_UP,
            TurbineConstants.ACTION_EVENT_BUBBLE_EXCEPTION_UP_DEFAULT);

    if (log.isDebugEnabled()){
    log.debug(submitValueKey
        ? "ActionEvent accepts only eventSubmit_do Keys with a value != 0"
        : "ActionEvent accepts all eventSubmit_do Keys");
    log.debug(bubbleUpException
          ? "ActionEvent will bubble exceptions up to Turbine.handleException() method"
          : "ActionEvent will not bubble exceptions up.");
    }
  }

  /**
   * This overrides the default Action.perform() to execute the
   * doEvent() method. If that fails, then it will execute the
   * doPerform() method instead.
   * @deprecated Use PipelineData version instead.
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  @Deprecated
    @Override
    protected void perform(RunData data)
      throws Exception
  {
    try
    {
      executeEvents(data);
    }
    catch (NoSuchMethodException e)
    {
      doPerform(data);
    }
  }

  /**
   * This overrides the default Action.perform() to execute the
   * doEvent() method. If that fails, then it will execute the
   * doPerform() method instead.
   *
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  @Override
    protected void perform(PipelineData pipelineData)
      throws Exception
  {
    try
    {
      executeEvents(pipelineData);
    }
    catch (NoSuchMethodException e)
    {
      doPerform(pipelineData);
    }
  }


  /**
   * This method should be called to execute the event based system.
   *
   * @deprecated Use PipelineData version instead.
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  @Deprecated
    public void executeEvents(RunData data)
      throws Exception
  {
    // Name of the button.
    String theButton = null;
    // Parameter parser.
    ParameterParser pp = data.getParameters();

    String button = pp.convert(BUTTON);
    String key = null;

    // Loop through and find the button.
    for (Iterator it = pp.keySet().iterator(); it.hasNext();)
    {
      key = (String) it.next();
      if (key.startsWith(button))
      {
        if (considerKey(key, pp))
        {
          theButton = formatString(key, pp);
          break;
        }
      }
    }

    if (theButton == null)
    {
      throw new NoSuchMethodException("ActionEvent: The button was null");
    }

    Method method = null;

    try
    {
      method = getClass().getMethod(theButton, methodParams);
      Object[] methodArgs = new Object[] { data };

      if (log.isDebugEnabled())
      {
        log.debug("Invoking " + method);
      }

      method.invoke(this, methodArgs);
    }
    catch (InvocationTargetException ite)
    {
      Throwable t = ite.getTargetException();
      log.error("Invokation of " + method , t);
    }
    finally
    {
      pp.remove(key);
    }
  }

  /**
   * This method should be called to execute the event based system.
   *
   * @param data Turbine information.
   * @exception Exception a generic exception.
   */
  public void executeEvents(PipelineData pipelineData)
      throws Exception
  {

      RunData data = getRunData(pipelineData);

    // Name of the button.
    String theButton = null;
    // Parameter parser.
    ParameterParser pp = data.getParameters();

    String button = pp.convert(BUTTON);
    String key = null;

    // Loop through and find the button.
    for (Iterator it = pp.keySet().iterator(); it.hasNext();)
    {
      key = (String) it.next();
      if (key.startsWith(button))
      {
        if (considerKey(key, pp))
        {
          theButton = formatString(key, pp);
          break;
        }
      }
    }

    if (theButton == null)
    {
      throw new NoSuchMethodException("ActionEvent: The button was null");
    }

    Method method = null;

    try
    {
      method = getClass().getMethod(theButton, methodParams);
      Object[] methodArgs = new Object[] { pipelineData };

      if (log.isDebugEnabled())
      {
        log.debug("Invoking " + method);
      }

      method.invoke(this, methodArgs);
    }
    catch (InvocationTargetException ite)
    {
      Throwable t = ite.getTargetException();
      log.error("Invokation of " + method , t);
    }
    finally
    {
      pp.remove(key);
    }
  }



  /**
   * This method does the conversion of the lowercase method name
   * into the proper case.
   *
   * @param input The unconverted method name.
   * @param pp The parameter parser (for correct folding)
   * @return A string with the method name in the proper case.
   */
  protected final String formatString(String input, ParameterParser pp)
  {
    String tmp = input;

    if (StringUtils.isNotEmpty(input))
    {
      tmp = input.toLowerCase();

      // Chop off suffixes (for image type)
      input = (tmp.endsWith(".x") || tmp.endsWith(".y"))
          ? input.substring(0, input.length() - 2)
          : input;

      if (pp.getUrlFolding()
          != ParserService.URL_CASE_FOLDING_NONE)
      {
        tmp = input.toLowerCase().substring(BUTTON_LENGTH + METHOD_NAME_LENGTH);
        tmp = METHOD_NAME_PREFIX + StringUtils.capitalize(tmp);
      }
      else
      {
        tmp = input.substring(BUTTON_LENGTH);
      }
    }
    return tmp;
  }

  /**
   * Checks whether the selected key really is a valid event.
   *
   * @param key The selected key
   * @param pp The parameter parser to look for the key value
   *
   * @return true if this key is really an ActionEvent Key
   */
  protected boolean considerKey(String key, ParameterParser pp)
  {
    if (!submitValueKey)
    {
      log.debug("No Value required, accepting " + key);
      return true;
    }
    else
    {
      // If the action.eventsubmit.needsvalue key is true,
      // events with a "0" or empty value are ignored.
      // This can be used if you have multiple eventSubmit_do<xxx>
      // fields in your form which are selected by client side code,
      // e.g. JavaScript.
      //
      // If this key is unset or missing, nothing changes for the
      // current behaviour.
      //
      String keyValue = pp.getString(key);
      log.debug("Key Value is " + keyValue);
      if (StringUtils.isEmpty(keyValue))
      {
        log.debug("Key is empty, rejecting " + key);
        return false;
      }

      try
      {
        if (Integer.parseInt(keyValue) != 0)
        {
          log.debug("Integer != 0, accepting " + key);
          return true;
        }
      }
      catch (NumberFormatException nfe)
      {
        // Not a number. So it might be a
        // normal Key like "continue" or "exit". Accept
        // it.
        log.debug("Not a number, accepting " + key);
        return true;
      }
    }
    log.debug("Rejecting " + key);
    return false;
  }
}
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