org.apache.turbine.modules

## Class ActionEvent

- java.lang.Object
- - org.apache.turbine.modules.Assembler
  - - org.apache.turbine.modules.Action
    - - org.apache.turbine.modules.ActionEvent

- Direct Known Subclasses:
    VelocityActionEvent

      public abstract class ActionEvent
      extends Action

  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(PipelineData data)" method executed. If for any reason, it was not able to execute the method, it will fall back to executing the doPerform() method which is required to be implemented.

  Limitations:

  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.

  Thus, the convention is this:

  - The variable name MUST have the prefix "eventSubmit_".
  - The variable name after the prefix MUST begin with the letters "do".
  - The first letter after the "do" will be capitalized and the rest will be lowercase
  If you follow these conventions, then you should be ok with your method naming in your Action class.
  Version:
    $Id: ActionEvent.java 1812628 2017-10-19 12:34:25Z gk $
  Author:
    Jon S. Stevens , Henning P. Schmiedehausen, Quinton McCombs, Peter Courcoux

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected boolean` | `bubbleUpException` 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 static String` | `BUTTON` The name of the button to look for.
    `protected static int` | `BUTTON_LENGTH` The length of the button to look for.
    `protected static String` | `DEFAULT_METHOD` The default method.
    `protected static int` | `LENGTH` The length of the button to look for.
    `protected org.apache.commons.logging.Log` | `log` Logging
    `protected static int` | `METHOD_NAME_LENGTH` The length of the method name.
    `protected static String` | `METHOD_NAME_PREFIX` The prefix of the method name.

    - ### Fields inherited from class org.apache.turbine.modules.Action

      `CACHE_SIZE_DEFAULT, CACHE_SIZE_KEY, NAME, PREFIX`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ActionEvent()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected boolean` | `considerKey(String key, org.apache.fulcrum.parser.ParameterParser pp)` Checks whether the selected key really is a valid event.
    `void` | `doPerform(PipelineData pipelineData)` This overrides the default Action.doPerform() to execute the doEvent() method.
    `protected void` | `executeEvents(org.apache.fulcrum.parser.ParameterParser pp, Class<?>[] signature, Object[] parameters)` This method should be called to execute the event based system.
    `protected String` | `formatString(String input, org.apache.fulcrum.parser.ParameterParser pp)` This method does the conversion of the lowercase method name into the proper case.
    `protected Method` | `getMethod(String name, Class<?>[] signature, org.apache.fulcrum.parser.ParameterParser pp)` Retrieve a method of the given name and signature.

    - ### Methods inherited from class org.apache.turbine.modules.Action

      `getPrefix, perform`

    - ### Methods inherited from class org.apache.turbine.modules.Assembler

      `getRunData`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### log

          protected org.apache.commons.logging.Log log

      Logging

    - #### BUTTON

          protected static final String BUTTON

      The name of the button to look for.
      See Also:
        Constant Field Values

    - #### BUTTON_LENGTH

          protected static final int BUTTON_LENGTH

      The length of the button to look for.

    - #### DEFAULT_METHOD

          protected static final String DEFAULT_METHOD

      The default method.
      See Also:
        Constant Field Values

    - #### METHOD_NAME_PREFIX

          protected static final String METHOD_NAME_PREFIX

      The prefix of the method name.
      See Also:
        Constant Field Values

    - #### METHOD_NAME_LENGTH

          protected static final int METHOD_NAME_LENGTH

      The length of the method name.

    - #### LENGTH

          protected static final int LENGTH

      The length of the button to look for.

    - #### bubbleUpException

          protected boolean bubbleUpException

      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.

  - ### Constructor Detail

    - #### ActionEvent

          public ActionEvent()

  - ### Method Detail

    - #### getMethod

          protected Method getMethod(String name,
                         Class<?>[] signature,
                         org.apache.fulcrum.parser.ParameterParser pp)
                              throws NoSuchMethodException

      Retrieve a method of the given name and signature. The value is cached.
      Parameters:
        `name` - the name of the method
        `signature` - an array of classes forming the signature of the method
        `pp` - ParameterParser for correct folding
      Returns:
        the method object
      Throws:
        `NoSuchMethodException` - if the method does not exist

    - #### doPerform

          public void doPerform(PipelineData pipelineData)
                         throws Exception

      This overrides the default Action.doPerform() to execute the doEvent() method. If that fails, then it will execute the doPerform() method instead.
      Specified by:
        `doPerform` in class `Action`
      Parameters:
        `pipelineData` - Turbine information.
      Throws:
        `Exception` - a generic exception.

    - #### executeEvents

          protected void executeEvents(org.apache.fulcrum.parser.ParameterParser pp,
                           Class<?>[] signature,
                           Object[] parameters)
                                throws Exception

      This method should be called to execute the event based system.
      Parameters:
        `pp` - the parameter parser
        `signature` - the signature of the method to call
        `parameters` - the parameters for the method to call
      Throws:
        `Exception` - a generic exception.

    - #### formatString

          protected String formatString(String input,
                            org.apache.fulcrum.parser.ParameterParser pp)

      This method does the conversion of the lowercase method name into the proper case.
      Parameters:
        `input` - The unconverted method name.
        `pp` - The parameter parser (for correct folding)
      Returns:
        A string with the method name in the proper case.

    - #### considerKey

          protected boolean considerKey(String key,
                            org.apache.fulcrum.parser.ParameterParser pp)

      Checks whether the selected key really is a valid event.
      Parameters:
        `key` - The selected key
        `pp` - The parameter parser to look for the key value
      Returns:
        true if this key is really an ActionEvent Key

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