org.jutil.predicate
Class TotalPredicate

java.lang.Object
  |
  +--org.jutil.predicate.AbstractPredicate
        |
        +--org.jutil.predicate.TotalPredicate

All Implemented Interfaces:

CollectionOperator, Predicate

Direct Known Subclasses:

NegationAsFailure, PrimitiveTotalPredicate

public abstract class TotalPredicate

extends AbstractPredicate

A class of Predicates that do not throw exceptions.

If your predicate don't throw exceptions, you should subclass TotalPredicate. This saves the client from writing useless try-catch blocks.

Typically, this class will be used as an anonymous inner class as follows:

TotalPredicate myPredicate = new TotalPredicate() {
            public boolean eval(Object o) {
              //calculate boolean value
              //using the given object
            }
            public int nbSubPredicates() {
              // ...
            }
            public List getSubPredicates() {
              // ...
            }
          };
 

Note that if your predicate doesn't contain any sub predicates, it should extend PrimitiveTotalPredicate instead of this class.

Field Summary
static java.lang.String	CVS_REVISION

 

Constructor Summary

TotalPredicate()

 

Method Summary
int	count(java.util.Collection collection)           See superclass
abstract  boolean	eval(java.lang.Object object)           Evaluate this Predicate for the given object.
boolean	exists(java.util.Collection collection)           See superclass
void	filter(java.util.Collection collection)           See superclass
boolean	forall(java.util.Collection collection)           See superclass
boolean	isValidElement(java.lang.Object o)           This model method is supplied to make proving the correctness of a subclass easier.

 

Methods inherited from class org.jutil.predicate.AbstractPredicate

equals, nbSubPredicates

 

Methods inherited from class java.lang.Object

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

 

Methods inherited from interface org.jutil.predicate.Predicate

getSubPredicates

 

Field Detail

CVS_REVISION

public static final java.lang.String CVS_REVISION

TotalPredicate

public TotalPredicate()

eval

public abstract boolean eval(java.lang.Object object)

Description copied from interface: Predicate

Evaluate this Predicate for the given object.

Specifications:

     also

public behavior
signals (Exception) false;

Specifications inherited from overridden method in interface Predicate:

public behavior
ensures \result == true|\result == false;
signals (Exception) !isValidElement(object);

isValidElement

public boolean isValidElement(java.lang.Object o)

Description copied from interface: CollectionOperator

This model method is supplied to make proving the correctness of a subclass easier. It offers a tunnel for information the caller of methods that operate on the collection.

Most often, this information concerns the type of the elements and them not being null.

The algorithm does not use this method, so we will not force subclasses to implement it. A strengthened specification should be given to enable proving the correctness of a specific operator.

This is actually an abstract precondition as used in Eiffel.

Specifications:

     also

public behavior
ensures \result == true;

Specifications inherited from overridden method in interface CollectionOperator:

public behavior
ensures ( \forall Object o1; ; ( \forall Object o2; (o2 != null)&&o2.equals(o1); isValidElement(o1) == isValidElement(o2)));

exists

public boolean exists(java.util.Collection collection)

Description copied from class: AbstractPredicate

See superclass

Specifications:

     also

public behavior
signals (Exception) false;

Specifications inherited from overridden method in class AbstractPredicate:
      --- None ---

Specifications inherited from overridden method in interface Predicate:

public behavior
ensures collection != null ==> \result == ( \exists Object o; Collections.containsExplicitly(collection,o); eval(o) == true);
ensures collection == null ==> \result == false;
signals (ConcurrentModificationException) (* The collection was modified while accumulating *);
signals (Exception) (collection != null)&&( \exists Object o; (collection != null)&&Collections.containsExplicitly(collection,o); !isValidElement(o));

forall

public boolean forall(java.util.Collection collection)

Description copied from class: AbstractPredicate

See superclass

Specifications:

     also

public behavior
signals (Exception) false;

Specifications inherited from overridden method in class AbstractPredicate:
      --- None ---

Specifications inherited from overridden method in interface Predicate:

public behavior
ensures collection != null ==> \result == ( \forall Object o; Collections.containsExplicitly(collection,o); eval(o) == true);
ensures collection == null ==> \result == true;
signals (ConcurrentModificationException) (* The collection was modified while accumulating *);
signals (Exception) (collection != null)&&( \exists Object o; (collection != null)&&Collections.containsExplicitly(collection,o); !isValidElement(o));

count

public int count(java.util.Collection collection)

Description copied from class: AbstractPredicate

See superclass

Specifications:

     also

public behavior
signals (Exception) false;

Specifications inherited from overridden method in class AbstractPredicate:
      --- None ---

Specifications inherited from overridden method in interface Predicate:

public behavior
ensures collection != null ==> \result == ( \num_of Object o; Collections.containsExplicitly(collection,o); eval(o) == true);
ensures collection == null ==> \result == 0;
signals (ConcurrentModificationException) (* The collection was modified while accumulating *);
signals (Exception) (collection != null)&&( \exists Object o; (collection != null)&&Collections.containsExplicitly(collection,o); !isValidElement(o));

filter

public void filter(java.util.Collection collection)

Description copied from class: AbstractPredicate

See superclass

Specifications:

     also

public behavior
signals (Exception) false;

Specifications inherited from overridden method in class AbstractPredicate:
      --- None ---

Specifications inherited from overridden method in interface Predicate:

public behavior
ensures collection != null ==> ( \forall Object o; Collections.containsExplicitly(collection,o); eval(o) == true);
ensures collection != null ==> ( \forall Object o; \old(Collections.containsExplicitly(collection,o)); (eval(o) == true) ==> (Collections.nbExplicitOccurrences(o,collection) == \old(Collections.nbExplicitOccurrences(o,collection))));
signals (ConcurrentModificationException) (* The collection was modified while accumulating *);
signals (Exception) (collection != null)&&( \exists Object o; (collection != null)&&Collections.containsExplicitly(collection,o); !isValidElement(o));