com.sun.jini.discovery

Class DiscoveryConstraints.ConstraintReducer

java.lang.Object

com.sun.jini.discovery.DiscoveryConstraints.ConstraintReducer

Direct Known Subclasses:

DiscoveryConstraints.MaxValueReducer

Enclosing class:

DiscoveryConstraints

private static class DiscoveryConstraints.ConstraintReducer
extends Object

Utility for reducing constraints of a given type into a base set of alternatives. For each type of constraints that it reduces, this class makes the simplifying assumption that failure to reduce constraints of that type into a single (perhaps one element) set of alternatives represents a constraint conflict--i.e., that two disjoint instances of the constraint type cannot be applied to the same operation. While this restriction does not hold across all possible constraints, it is satisfied by the particular constraint types that DiscoveryConstraints handles. If this utility encounters a set of alternatives containing instances of both the type to reduce as well as other constraint types, then it ignores the instances of the other types, treating the set as if it can only be satisfied by the alternatives of the targeted type. This may in some cases cause false positives when detecting conflicts in constraints containing alternatives of mixed type; however, it should never result in false negatives.

Field Summary

Fields

Modifier and Type	Field and Description
private Class	targetClass

Constructor Summary

Constructors

Constructor and Description
DiscoveryConstraints.ConstraintReducer(Class targetClass) Creates reducer that operates on instances of the given constraint class.

Method Summary

Methods

Modifier and Type	Method and Description
private Set	getTargetInstances(Set set)
(package private) Set	reduce(InvocationConstraints constraints) Returns the reduction of the given constraints into a single set of alternatives for the target class.
private Set	reduce(Set reduced, Set constraints, boolean required)
(package private) Set	reduce0(Set reduced, Set toReduce) Returns the reduction (intersection and compaction) of a new set of alternative constraints, all instances of the target class, with a previously reduced set (null if no other constraints have been reduced yet).

Methods inherited from class java.lang.Object

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

Field Detail

targetClass

private final Class targetClass

Constructor Detail

DiscoveryConstraints.ConstraintReducer

DiscoveryConstraints.ConstraintReducer(Class targetClass)

Creates reducer that operates on instances of the given constraint class.

Method Detail

reduce

Set reduce(InvocationConstraints constraints)
     throws UnsupportedConstraintException

Returns the reduction of the given constraints into a single set of alternatives for the target class. Returns an empty set if no constraints of the target class are specified. Throws UnsupportedConstraintException if the constraints conflict.

Throws:

UnsupportedConstraintException

reduce0

Set reduce0(Set reduced,
          Set toReduce)

Returns the reduction (intersection and compaction) of a new set of alternative constraints, all instances of the target class, with a previously reduced set (null if no other constraints have been reduced yet). Returns an empty set if elements in the sets conflict. This method can be overridden by subclasses for constraints with particular reduction semantics; the default implementation of this method returns the intersection of the two sets.

reduce

private Set reduce(Set reduced,
         Set constraints,
         boolean required)
            throws UnsupportedConstraintException

Throws:

UnsupportedConstraintException

getTargetInstances

private Set getTargetInstances(Set set)