/*
* Copyright (C) NetStruxr, Inc. All rights reserved.
*
* This software is published under the terms of the NetStruxr
* Public Software License version 0.5, a copy of which has been
* included with this distribution in the LICENSE.NPL file. */
package er.directtoweb.assignments.delayed;
import java.util.Enumeration;
import org.apache.log4j.Logger;
import com.webobjects.directtoweb.D2WContext;
import com.webobjects.eocontrol.EOKeyValueUnarchiver;
import com.webobjects.eocontrol.EOQualifier;
import com.webobjects.foundation.NSArray;
import com.webobjects.foundation.NSDictionary;
import com.webobjects.foundation.NSKeyValueCoding;
import com.webobjects.foundation.NSMutableArray;
import er.directtoweb.assignments.ERDComputingAssignmentInterface;
/**
* DelayedConditionalAssignment expects a value dictionary that contains the
* following keys:
* - qualifierFormat (see EOQualifier for more info)
* - args: the arguments used by the qualifier format
* - trueValue: the value used if the condition returns true
* - falseValue: the value used if the condition returns false
* To specify a null value for true and false values simply ommit the
* corresponding key.
* The condition is evaluated
* every time that the propertyKey is requested thus making the rule system
* a lot more dynamic.
*/
public class ERDDelayedConditionalAssignment extends ERDDelayedAssignment implements ERDComputingAssignmentInterface {
/**
* Do I need to update serialVersionUID?
* See section 5.6 <cite>Type Changes Affecting Serialization</cite> on page 51 of the
* <a href="http://java.sun.com/j2se/1.4/pdf/serial-spec.pdf">Java Object Serialization Spec</a>
*/
private static final long serialVersionUID = 1L;
/** logging support */
public final static Logger log = Logger.getLogger("er.directtoweb.rules.DelayedConditionalAssignment");
/**
* 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.
* @param eokeyvalueunarchiver to be unarchived
* @return decoded assignment of this class
*/
public static Object decodeWithKeyValueUnarchiver(EOKeyValueUnarchiver eokeyvalueunarchiver) {
return new ERDDelayedConditionalAssignment(eokeyvalueunarchiver);
}
/**
* Public constructor
* @param u key-value unarchiver used when unarchiving
* from rule files.
*/
public ERDDelayedConditionalAssignment(EOKeyValueUnarchiver u) { super(u); }
/**
* Public constructor
* @param key context key
* @param value of the assignment
*/
public ERDDelayedConditionalAssignment(String key, Object value) { super(key,value); }
public NSArray _dependentKeys;
/**
* Implementation of the {@link er.directtoweb.assignments.ERDComputingAssignmentInterface}. This
* assignment depends upon all of the qualifier keys from the formed
* qualifier of the value of this assignment. This array of keys is
* used when constructing the significant keys for the passed in keyPath.
* @param keyPath to compute significant keys for.
* @return array of context keys this assignment depends upon.
*/
public NSArray dependentKeys(String keyPath) {
if (_dependentKeys==null) {
NSDictionary conditionAssignment;
try {
conditionAssignment = (NSDictionary)value();
} catch (ClassCastException e) {
log.error("expected a NSDictionary object but received "+value(), e);
throw e;
}
String qualFormat =
(String)conditionAssignment.objectForKey("qualifierFormat");
NSArray args = (NSArray)conditionAssignment.objectForKey("args");
if (log.isDebugEnabled()) log.debug("parsing "+qualFormat);
EOQualifier qualifier =
EOQualifier.qualifierWithQualifierFormat(qualFormat, args);
if (log.isDebugEnabled())
log.debug("Qualifier keys: " + qualifier.allQualifierKeys());
_dependentKeys=qualifier.allQualifierKeys().allObjects();
}
return _dependentKeys;
}
/**
* This method is called whenever the propertyKey is requested,
* but the value in the cache is actually a rule.
*/
@Override
public Object fireNow(D2WContext c) {
Object result = null;
NSDictionary conditionAssignment = (NSDictionary)value();
String qualFormat =
(String)conditionAssignment.objectForKey("qualifierFormat");
NSArray args = (NSArray)conditionAssignment.objectForKey("args");
if (args != null && args.count() > 0) {
// Need to resolve the args from the context.
NSMutableArray argHolder = new NSMutableArray(args.count());
for (Enumeration argEnumerator = args.objectEnumerator(); argEnumerator.hasMoreElements();) {
Object arg = argEnumerator.nextElement();
if (arg instanceof String && ((String)arg).length() > 1 && ((String)arg).charAt(0) == '^') {
Object value = c.valueForKeyPath(((String)arg).substring(1, ((String)arg).length()));
if (value == null)
value = NSKeyValueCoding.NullValue;
argHolder.addObject(value);
} else {
argHolder.addObject(arg);
}
}
}
if (log.isDebugEnabled()) {
log.debug("Entity \"" + c.entity().name() + "\"");
log.debug("Object " + c.valueForKey("object"));
log.debug("qualifierFormat " + qualFormat);
log.debug("ardgs " + args);
}
EOQualifier qualifier = EOQualifier.qualifierWithQualifierFormat(qualFormat, args);
if (log.isDebugEnabled()) {
log.debug("Qualifier keys: " + qualifier.allQualifierKeys());
log.debug("Qualifier : " + qualifier);
log.debug("DelayedConditonalQualifier: " + qualifier);
}
if (qualifier.evaluateWithObject(c)) {
result = conditionAssignment.objectForKey("trueValue");
if (log.isDebugEnabled())
log.debug("trueValue = " + result);
} else {
result = conditionAssignment.objectForKey("falseValue");
if (log.isDebugEnabled())
log.debug("falseValue = " + result);
}
return result;
}
}