er.extensions.components._private

Class ERXWORepetition

java.lang.Object

com.webobjects.appserver.WOElement

com.webobjects.appserver.WODynamicElement

com.webobjects.appserver._private.WODynamicGroup

er.extensions.components._private.ERXWORepetition

public class ERXWORepetition
extends com.webobjects.appserver._private.WODynamicGroup

Replacement for WORepetition. It is installed via ERXPatcher.setClassForName(ERXWORepetition.class, "WORepetition") into the runtime system, so you don't need to reference it explicitly.

• adds support for List and arrays (e.g. String[]), in addition to NSArray and Vector (which is a List in 1.4). This is listed as Radar #3325342 since June 2003.
• help with backtracking issues by adding not only the current index, but also the current object's hash code to the element id, so it looks like "x.y.12345.z".
  If they don't match when invokeAction is called, the list is searched for a matching object. If none is found, then:
  • if the property er.extensions.ERXWORepetition.raiseOnUnmatchedObject=true - an ERXWORepetition.UnmatchedObjectException is thrown
  • if notFoundMarker is bound, that is used for the item in the repetition. This can be used to flag special handling in the action method, possibly useful for Ajax requests
  • otherwise, the action is ignored
  This feature is turned on globally if er.extensions.ERXWORepetition.checkHashCodes=true or on a per-component basis by setting the checkHashCodes binding to true or false.
  Known issues:
  • you can't re-generate your list by creating new objects between the appendToReponse and the next takeValuesFromRequest unless you use uniqueKey and the value for that key is consistent across the object instances
    When doing this by fetching EOs, this is should not a be problem, as the EO most probably has the same hashCode if the EC stays the same.
  • Your moved object should still be in the list.
  • Form values are currently not fixed, which may lead to NullpointerExceptions or other failures. However, if they happen, by default you would have used the wrong values, so it may be arguable that having an error is better...

Note that this implementation adds a small amount of overhead due to the creation of the Context for each RR phase, but this is preferable to having to give so many parameters. As an alternative to the default use of System.identityHashCode to unique your items, you can set the binding "uniqueKey" to be a string keypath on your items that can return a unique key for the item. For instance, if you are using ERXGenericRecord, you can set uniqueKey = "rawPrimaryKey"; if your EO has an integer primary key, and this will make the uniquing value be the primary key instead of the hash code. While this reveals the primary keys of your items, the set of possible valid matches is still restricted to only those that were in the list to begin with, so no additional capabilities are available to users. uniqueKey does not have to return an integer.

Author:

ak

Bindings

Name	Description
list	the array or list of items to iterate over
item	the current item in the iteration
count	the total number of items to iterate over
index	the current index in the iteration
uniqueKey	a String keypath on item (relative to item, not relative to the component) returning a value whose toString() is unique for this component
checkHashCodes	if true, checks the validity of repetition references during the RR loop
raiseOnUnmatchedObject	if true, an exception is thrown when the repetition does not find a matching object
debugHashCodes	if true, prints out hashcodes for each entry in the repetition as it is traversed
batchFetch	a comma-separated list of keypaths on the "list" array binding to batch fetch
eoSupport	try to use globalIDs to determine the hashCode for EOs
notFoundMarker	used for the item in the repetition if checkHashCodes is true, don't bind directly to null as that will be translated to false

Properties

Name	Description
er.extensions.ERXWORepetition.checkHashCodes	add hash codes to element IDs so backtracking can be controlled
er.extensions.ERXWORepetition.raiseOnUnmatchedObject	if an object wasn't found, raise an exception (if unset, the wrong object is used)
er.extensions.ERXWORepetition.eoSupport	use hash code of GlobalID instead of object's hash code if it is an EO

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ERXWORepetition.Context WOElements must be reentrant, so we need a context object or will have to add the parameters to every method.
static class	ERXWORepetition.UnmatchedObjectException

Field Summary

Fields

Modifier and Type	Field and Description
protected WOAssociation	_batchFetch
protected WOAssociation	_checkHashCodes
protected WOAssociation	_count
protected WOAssociation	_debugHashCodes
protected WOAssociation	_eoSupport
protected WOAssociation	_index
protected WOAssociation	_item
protected WOAssociation	_list
protected WOAssociation	_notFoundMarker
protected WOAssociation	_raiseOnUnmatchedObject
protected WOAssociation	_uniqueKey

Fields inherited from class com.webobjects.appserver._private.WODynamicGroup

_children

Fields inherited from class com.webobjects.appserver.WODynamicElement

_ConstructorParameters

Constructor Summary

Constructors

Constructor and Description
ERXWORepetition(String string, NSDictionary<String,WOAssociation> associations, WOElement woelement) Designated Constructor.

Method Summary

Modifier and Type	Method and Description
protected void	_cleanupAfterIteration(int i, WOContext wocontext, WOComponent wocomponent) Cleans the WOContext after the loop iteration.
protected int	_count(ERXWORepetition.Context context, WOComponent wocomponent)
protected void	_failCreation(String message) Utility to throw an exception if the bindings are incomplete.
protected String	_indexOfChosenItem(WORequest worequest, WOContext wocontext)
protected String	_indexStringForSenderAndElement(String senderID, String elementID) Fills the context with the object given in the "list" binding.
protected void	_prepareForIterationWithIndex(ERXWORepetition.Context context, int index, WOContext wocontext, WOComponent wocomponent, boolean checkHashCodes) Prepares the WOContext for the loop iteration.
void	appendToResponse(WOResponse woresponse, WOContext wocontext)
protected ERXWORepetition.Context	createContext(WOComponent wocomponent)
WOActionResults	invokeAction(WORequest worequest, WOContext wocontext)
void	takeValuesFromRequest(WORequest worequest, WOContext wocontext)
String	toString()

Methods inherited from class com.webobjects.appserver._private.WODynamicGroup

addChildElement, appendChildrenToResponse, childrenElements, EmptyGroup, hasChildrenElements, invokeChildrenAction, takeChildrenValuesFromRequest

Methods inherited from class java.lang.Object

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

Field Detail

_list

protected WOAssociation _list

_item

protected WOAssociation _item

_count

protected WOAssociation _count

_index

protected WOAssociation _index

_uniqueKey

protected WOAssociation _uniqueKey

_checkHashCodes

protected WOAssociation _checkHashCodes

_raiseOnUnmatchedObject

protected WOAssociation _raiseOnUnmatchedObject

_eoSupport

protected WOAssociation _eoSupport

_debugHashCodes

protected WOAssociation _debugHashCodes

_batchFetch

protected WOAssociation _batchFetch

_notFoundMarker

protected WOAssociation _notFoundMarker

Constructor Detail

ERXWORepetition

public ERXWORepetition(String string,
                       NSDictionary<String,WOAssociation> associations,
                       WOElement woelement)

Designated Constructor. Gets called by the template parser. Checks if the bindings are valid.

Parameters:

string -

associations -

woelement -

Method Detail

_failCreation

protected void _failCreation(String message)

Utility to throw an exception if the bindings are incomplete.

Parameters:

message -

toString

public String toString()

Overrides:

toString in class com.webobjects.appserver._private.WODynamicGroup

_prepareForIterationWithIndex

protected void _prepareForIterationWithIndex(ERXWORepetition.Context context,
                                             int index,
                                             WOContext wocontext,
                                             WOComponent wocomponent,
                                             boolean checkHashCodes)

Prepares the WOContext for the loop iteration.

Parameters:

context -

index -

wocontext -

wocomponent -

checkHashCodes -

_cleanupAfterIteration

protected void _cleanupAfterIteration(int i,
                                      WOContext wocontext,
                                      WOComponent wocomponent)

Cleans the WOContext after the loop iteration.

Parameters:

i -

wocontext -

wocomponent -

_indexStringForSenderAndElement

protected String _indexStringForSenderAndElement(String senderID,
                                                 String elementID)

Fills the context with the object given in the "list" binding.

Parameters:

senderID -

elementID -

Returns:

index string

_indexOfChosenItem

protected String _indexOfChosenItem(WORequest worequest,
                                    WOContext wocontext)

_count

protected int _count(ERXWORepetition.Context context,
                     WOComponent wocomponent)

createContext

protected ERXWORepetition.Context createContext(WOComponent wocomponent)

takeValuesFromRequest

public void takeValuesFromRequest(WORequest worequest,
                                  WOContext wocontext)

Overrides:

takeValuesFromRequest in class com.webobjects.appserver._private.WODynamicGroup

invokeAction

public WOActionResults invokeAction(WORequest worequest,
                                    WOContext wocontext)

Overrides:

invokeAction in class com.webobjects.appserver._private.WODynamicGroup

appendToResponse

public void appendToResponse(WOResponse woresponse,
                             WOContext wocontext)

Overrides:

appendToResponse in class com.webobjects.appserver._private.WODynamicGroup