er.directtoweb.assignments.delayed

Class ERDDelayedNonNullConditionalAssignment

java.lang.Object

com.webobjects.directtoweb.Assignment

er.directtoweb.assignments.delayed.ERDDelayedAssignment

er.directtoweb.assignments.delayed.ERDDelayedNonNullConditionalAssignment

All Implemented Interfaces:

EOKeyValueArchiving, Serializable

public class ERDDelayedNonNullConditionalAssignment
extends ERDDelayedAssignment

The delayed non-null conditional is a way to provide a branching result from a rule resolution. The value of this assignment must be a dictionary that has the following keys:

dictionary key "nonNullKeyPath":

key path to be tested for nullability off of the current D2W context.

dictionary key "trueValue":

value to be returned if the key path is not null.

dictionary key "falseValue":

value to be returned if the key path is null.

dictionary key "negate":

if true, returns trueValue when null and falseValue when not null.

dictionary key "localize":

if true, localizes the result before returning it

Because this assignment is a delayed assignment the above condition will be evaluated every time that the D2W fired rule cache resolves to a rule of this class.

Example usage. Let's imagine that a User has a relationship called toOwnedHouse this relationship is only set if the User is a home owner. Now let's imagine that we have a page configuration for displaying information about a User. One of the propertyKeys for this page configuration is 'residence' which is not an attribute or relationship off of the User object. Imagine that we have already built a custom component for displaying the address of either an owned house or a rented house for a given User. However we want the displayed name to be either "Rented House" or "Owned House" depending on if the User is a home owner. The usual approach would be to create two page configurations and set the displayNameForProperty to be different for each of these page configurations. However by using a DelayedNonNullConditionalAssignment we will only have to use a single page configuration. Using this rule:

 pageConfguration = 'InspectUser' AND propertyKey = 'residence' =>
 displayNameForProperty =
 {
        nonNullKeyPath = "object.toOwnedHouse";
        trueValue = "Owned House";
        falseValue = "Rented House";
 }

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.webobjects.eocontrol.EOKeyValueArchiving

EOKeyValueArchiving._NullValueSupport, EOKeyValueArchiving._NumberSupport, EOKeyValueArchiving._TimestampSupport, EOKeyValueArchiving.Awaking, EOKeyValueArchiving.FinishInitialization, EOKeyValueArchiving.Support

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.log4j.Logger	log logging support

Fields inherited from class com.webobjects.directtoweb.Assignment

KeyPathKey, ValueKey

Fields inherited from interface com.webobjects.eocontrol.EOKeyValueArchiving

_CLASS

Constructor Summary

Constructors

Constructor and Description
ERDDelayedNonNullConditionalAssignment(EOKeyValueUnarchiver u) Public constructor
ERDDelayedNonNullConditionalAssignment(String key, Object value) Public constructor

Method Summary

Modifier and Type	Method and Description
static Object	decodeWithKeyValueUnarchiver(EOKeyValueUnarchiver eokeyvalueunarchiver) Static constructor required by the EOKeyValueUnarchiver interface.
NSArray<String>	dependentKeys(String keyPath) Implementation of the ERDComputingAssignmentInterface.
Object	fireNow(com.webobjects.directtoweb.D2WContext c) Implementation of the abstract method from ERDDelayedAssignment.

Methods inherited from class er.directtoweb.assignments.delayed.ERDDelayedAssignment

fire

Methods inherited from class com.webobjects.directtoweb.Assignment

encodeWithKeyValueArchiver, keyPath, toString, value, value

Methods inherited from class java.lang.Object

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

Field Detail

log

public static final org.apache.log4j.Logger log

logging support

Constructor Detail

ERDDelayedNonNullConditionalAssignment

public ERDDelayedNonNullConditionalAssignment(EOKeyValueUnarchiver u)

Public constructor

Parameters:

u - key-value unarchiver used when unarchiving from rule files.

ERDDelayedNonNullConditionalAssignment

public ERDDelayedNonNullConditionalAssignment(String key,
                                              Object value)

Public constructor

Parameters:

key - context key

value - of the assignment

Method Detail

decodeWithKeyValueUnarchiver

public static Object decodeWithKeyValueUnarchiver(EOKeyValueUnarchiver eokeyvalueunarchiver)

Static constructor required by the EOKeyValueUnarchiver interface. If this isn't implemented then the default behavior is to construct the first super class that does implement this method. Very lame.

Parameters:

eokeyvalueunarchiver - to be unarchived

Returns:

decoded assignment of this class

dependentKeys

public NSArray<String> dependentKeys(String keyPath)

Implementation of the ERDComputingAssignmentInterface. This assignment depends upon an array composed of the single value "nonNullKeyPath" from the dictionary of the value of this assignment. This array of keys is used when constructing the significant keys for the passed in keyPath.

Parameters:

keyPath - to compute significant keys for.

Returns:

array of context keys this assignment depends upon.

fireNow

public Object fireNow(com.webobjects.directtoweb.D2WContext c)

Implementation of the abstract method from ERDDelayedAssignment. This method is called each time this Assignment is resolved from the rule firing cache. For the non-null conditional the dictionary key 'nonNullKeyPath' is checked against the current context. If the key path is indeed non-null then the object returned by the dictionary key 'trueValue' will be returned otherwise the object returned by the dictionary key 'falseValue' will be returned.

Specified by:

fireNow in class ERDDelayedAssignment

Parameters:

c - current D2W context

Returns:

Either the 'trueValue' or 'falseValue' depending on if the key path is non-null or null.