desmoj
Class Condition 
java.lang.Object
desmoj.NamedObject
desmoj.ModelComponent
desmoj.Condition
- public abstract class Condition
- extends ModelComponent
Derive from this class to create your own special objects to test for
certain conditions in your Model or Experiment.
Two methods for testing on conditions are provided:
- boolean check() : parameterless method to check for conditions
independent of any actual Entity
- boolean check(Entity e) : a method to check for certain conditions
on individual Entities or Processes
Override these methods to return
true whenever the model or
entity comply to the condition to be checked.
- Version:
- DESMO-J, Ver. 1.5 copyright (c) 2001 licensed under GNU GPL
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Constructor Summary |
Condition(Model owner,
java.lang.String name,
boolean showInTrace)
Constructs a condition with the given name and parameters for trace files. |
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Method Summary |
abstract boolean |
check()
Returns a boolean value indicating whether the condition is met or not. |
abstract boolean |
check(Entity e)
Returns a boolean showing whether the given entity complies to the
condition tested by this method or not. |
| Methods inherited from class desmoj.ModelComponent |
current, currentEntity, currentEvent, currentModel, currentSimProcess, currentTime, debugIsOn, debugOff, debugOn, epsilon, getModel, isExperimentCompatible, isModelCompatible, sendDebugNote, sendMessage, sendTraceNote, sendWarning, setOwner, skipTraceNote, skipTraceNote, traceIsOn, traceOff, traceOn |
Condition
public Condition(Model owner,
java.lang.String name,
boolean showInTrace)
- Constructs a condition with the given name and parameters for trace files.
check
public abstract boolean check()
- Returns a boolean value indicating whether the condition is met or not.
Override this abstract method and implement the specific
check
to return true if the tested condition conforms to your specified needs.
If a condition is used as a stop-condition for an experiment
beware that the simulation will run endless if your condition can't be met.
It is advisable to always use a time limit if you are not sure about
the condition in question.
This abstract method must be implemented to make sure the appropriate
result is returned.
check
public abstract boolean check(Entity e)
- Returns a boolean showing whether the given entity complies to the
condition tested by this method or not.
Inherit from this class and implement this abstract method
to return true if the passed entity conforms to your special condition.
Note that any type of entity can be contained in a queue, so it is
absolutely necessary to verify that the entity given as a parameter is
actually an object of the type of entity you want to check.
This can easily be done using the Java
instanceof operator.
To avoid runtime type mismatches always check for the appropriate type of
object before accessing the desired object's attributes or methods
like shown below:
// not sure about the special type of entity e
if ( ! e instanceof mySpecialEntity ) return false;
// now we can be sure to have the special type of entity to check
return ((mySpecialEntity)e).getSpecialEntityValue == neededValue;
The line above aborts all further tests when the passed entity is not of
the desired type. If we do have an entity of the right type, we can
check it and even use its specific methods. Note also, that using these
specific methods still requires a typecast. But since we have tested
for the right type of entity before, this runtime typecast should never
get into a situation to throw an exception.
This abstract method must be implemented to return the desired value.
JAVADOC |