Class Drop
- java.lang.Object
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- org.apache.jena.reasoner.rulesys.builtins.BaseBuiltin
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- org.apache.jena.reasoner.rulesys.builtins.Drop
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- All Implemented Interfaces:
Builtin
public class Drop extends BaseBuiltin
A variant of the "remove" builtin that will delete matched triples from the graph but will not trigger further rule processing for the removed triples. This makes it seriously non-monotonic but useful for rewrite rules.
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Field Summary
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Fields inherited from class org.apache.jena.reasoner.rulesys.builtins.BaseBuiltin
BASE_URI
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Constructor Summary
Constructors Constructor Description Drop()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.String
getName()
Return a name for this builtin, normally this will be the name of the functor that will be used to invoke it.void
headAction(Node[] args, int length, RuleContext context)
This method is invoked when the builtin is called in a rule head.boolean
isMonotonic()
Returns false if this builtin is non-monotonic.-
Methods inherited from class org.apache.jena.reasoner.rulesys.builtins.BaseBuiltin
bodyCall, checkArgs, getArg, getArgLength, getURI, isSafe
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Method Detail
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getName
public java.lang.String getName()
Return a name for this builtin, normally this will be the name of the functor that will be used to invoke it.
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headAction
public void headAction(Node[] args, int length, RuleContext context)
This method is invoked when the builtin is called in a rule head. Such a use is only valid in a forward rule.- Specified by:
headAction
in interfaceBuiltin
- Overrides:
headAction
in classBaseBuiltin
- Parameters:
args
- the array of argument values for the builtin, this is an array of Nodes.length
- the length of the argument list, may be less than the length of the args array for some rule enginescontext
- an execution context giving access to other relevant data
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isMonotonic
public boolean isMonotonic()
Returns false if this builtin is non-monotonic. This includes non-monotonic checks like noValue and non-monotonic actions like remove/drop. A non-monotonic call in a head is assumed to be an action and makes the overall rule and ruleset non-monotonic. Most JenaRules are monotonic deductive closure rules in which this should be false.- Specified by:
isMonotonic
in interfaceBuiltin
- Overrides:
isMonotonic
in classBaseBuiltin
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