Package net.jini.core.constraint

Class ConstraintAlternatives

java.lang.Object
net.jini.core.constraint.ConstraintAlternatives
All Implemented Interfaces:
Serializable, InvocationConstraint, RelativeTimeConstraint
public final class ConstraintAlternatives extends Object implements RelativeTimeConstraint, Serializable
Combines two or more constraint alternatives into a single overall constraint. The semantics of this aggregate constraint are that at least one of the individual constraint alternatives must be satisfied. The alternatives do not have to be instances of the same type, but they cannot themselves be ConstraintAlternatives instances.

Note that this class implements RelativeTimeConstraint even though the constraint elements might not implement RelativeTimeConstraint.

An instance containing an exhaustive list of alternatives (for example, an instance containing both ClientAuthentication.YES and ClientAuthentication.NO) serves no useful purpose, as a requirement or as a preference. A don't care condition should be expressed by the absence of constraints.

Since:
2.0
Author:
Sun Microsystems, Inc.
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    ConstraintAlternatives(Collection c)
    Creates an instance containing the specified alternative constraints, with duplicate constraints removed.
    ConstraintAlternatives(InvocationConstraint[] constraints)
    Creates an instance containing the specified alternative constraints, with duplicate constraints removed.

  • Method Summary

    Modifier and Type
    Method
    Description
    static InvocationConstraint
    create(Collection c)
    Returns a constraint representing the specified alternative constraints, with duplicate constraints removed.
    static InvocationConstraint
    create(InvocationConstraint[] constraints)
    Returns a constraint representing the specified alternative constraints, with duplicate constraints removed.
    Set
    elements()
    Returns an immutable set of all of the constraints.
    boolean
    equals(Object obj)
    Two instances of this class are equal if they have the same constraints (ignoring order).
    int
    hashCode()
    Returns a hash code value for this object.
    InvocationConstraint
    makeAbsolute(long baseTime)
    Returns a constraint equal to the result of taking the constraints in this instance, replacing each constraint that is an instance of RelativeTimeConstraint with the result of invoking that constraint's makeAbsolute method with the specified base time, and invoking the create method of this class with the revised collection of constraints.
    String
    toString()
    Returns a string representation of this object.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • ConstraintAlternatives

      public ConstraintAlternatives(InvocationConstraint[] constraints)
      Creates an instance containing the specified alternative constraints, with duplicate constraints removed. The argument passed to this constructor is neither modified nor retained; subsequent changes to that argument have no effect on the instance created.
      Parameters:
      constraints - the alternative constraints
      Throws:
      NullPointerException - if the argument is null or any element is null
      IllegalArgumentException - if any of the elements are instances of ConstraintAlternatives, or if fewer than two elements remain after duplicate constraints are removed

    • ConstraintAlternatives

      public ConstraintAlternatives(Collection c)
      Creates an instance containing the specified alternative constraints, with duplicate constraints removed. The argument passed to this constructor is neither modified nor retained; subsequent changes to that argument have no effect on the instance created.
      Parameters:
      c - the alternative constraints
      Throws:
      NullPointerException - if the argument is null or any element is null
      IllegalArgumentException - if any of the elements are instances of ConstraintAlternatives, or if the elements are not all instances of InvocationConstraint, or if fewer than two elements remain after duplicate constraints are removed

  • Method Details

    • create

      public static InvocationConstraint create(InvocationConstraint[] constraints)
      Returns a constraint representing the specified alternative constraints, with duplicate constraints removed. If a single constraint remains after duplicates are removed, then that constraint is returned, otherwise an instance of ConstraintAlternatives containing the remaining constraints is returned. The argument passed to this method is neither modified nor retained; subsequent changes to that argument have no effect on the instance created.
      Parameters:
      constraints - the alternative constraints
      Returns:
      a constraint representing the specified alternative constraints, with duplicate constraints removed
      Throws:
      NullPointerException - if the argument is null or any element is null
      IllegalArgumentException - if the argument is empty, or if any of the elements are instances of ConstraintAlternatives

    • create

      public static InvocationConstraint create(Collection c)
      Returns a constraint representing the specified alternative constraints, with duplicate constraints removed. If a single constraint remains after duplicates are removed, then that constraint is returned, otherwise an instance of ConstraintAlternatives containing the remaining constraints is returned. The argument passed to this method is neither modified nor retained; subsequent changes to that argument have no effect on the instance created.
      Parameters:
      c - the alternative constraints
      Returns:
      a constraint representing the specified alternative constraints, with duplicate constraints removed
      Throws:
      NullPointerException - if the argument is null or any element is null
      IllegalArgumentException - if the argument is empty, or if any of the elements are instances of ConstraintAlternatives, or if the elements are not all instances of InvocationConstraint

    • elements

      public Set elements()
      Returns an immutable set of all of the constraints. Any attempt to modify this set results in an UnsupportedOperationException being thrown.
      Returns:
      an immutable set of all of the constraints

    • makeAbsolute

      public InvocationConstraint makeAbsolute(long baseTime)
      Returns a constraint equal to the result of taking the constraints in this instance, replacing each constraint that is an instance of RelativeTimeConstraint with the result of invoking that constraint's makeAbsolute method with the specified base time, and invoking the create method of this class with the revised collection of constraints.
      Specified by:
      makeAbsolute in interface RelativeTimeConstraint
      Parameters:
      baseTime - an absolute time, specified in milliseconds from midnight, January 1, 1970 UTC
      Returns:
      a constraint that has the relative times converted to absolute times by adding the specified absolute time to each relative time

    • hashCode

      public int hashCode()
      Returns a hash code value for this object.
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Two instances of this class are equal if they have the same constraints (ignoring order).
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Returns a string representation of this object.
      Overrides:
      toString in class Object