Oracle Coherence for C++ API
Release 3.7.1.0

E22845-01

WrapperCollections::AbstractWrapperCollection Class Reference

#include <coherence/util/WrapperCollections.hpp>

Inherits Object, and Collection.

Inherited by ConverterCollections::ConverterCollection, and TypedCollections::TypedCollection.

List of all members.


Detailed Description

Collection implementation which delegates all calls to another Collection.
 

Public Types

typedef spec::Handle Handle
 AbstractWrapperCollection Handle definition.
typedef spec::View View
 AbstractWrapperCollection View definition.
typedef spec::Holder Holder
 AbstractWrapperCollection Holder definition.

Public Member Functions

virtual size32_t size () const
 Return the number of elements in this collection.

Returns:
the number of elements in this collection
virtual bool isEmpty () const
 Determine whether this collection contains any elements.

Returns:
true if this collection has no elements
virtual bool contains (Object::View v) const
 Determine if this collection contains the specified element.

Parameters:
 v the element to test for containment
Returns:
true iff this collection contains the given element
virtual Iterator::Handle iterator () const
 Return an Iterator over this collection.

Returns:
an Iterator over this collection
virtual Muterator::Handle iterator ()
 Return an Iterator over this collection.

Returns:
an Iterator over this collection
virtual
ObjectArray::Handle 
toArray (ObjectArray::Handle hao=NULL) const
 Return the contents of this collection as an ObjectArray.

If the collection fits in the specified array, it is returned, otherwise, a new array is allocated that is the size of this collection.

If this collection fits in the array with aditional room then the element in the array immediately following the end of the collection is set to NULL. This can be useful in determining the length of this collection if the caller knows that the collection does not contain any NULL elements.

Parameters:
 hao an array in which to store the collection's contents
Returns:
a ObjectArray containing all the elements of the collection in the same order as returned by the collection's Iterator
See also:
Iterator
virtual bool add (Object::Holder oh)
 Add the given element to this collection.

Parameters:
 oh the element to add
Returns:
true iff this collection was modified as a result of this operation
virtual bool remove (Object::View v)
 Remove the supplied element from this collection.

Parameters:
 v the element to remove
Returns:
true iff this collection was modified as a result of this operation
virtual bool containsAll (Collection::View vc) const
 Determine if this collection contains all elements from the supplied collection.

Parameters:
 vCol the collection of elements to test for containment
Returns:
true iff this collection contains all elements from the supplied collection
Exceptions:
 coherence::lang::NullPointerException if the specified collection is NULL
See also:
contains()
virtual bool addAll (Collection::View vc)
 Add all elements from the supplied collection to this collection.

Parameters:
 vCol the collection of elements to add
Returns:
true iff this collection was modified as a result of this operation
Exceptions:
 coherence::lang::NullPointerException if the specified collection is NULL
See also:
add()
virtual bool removeAll (Collection::View vc)
 Remove all instances of the elements in the supplied collection from this collection.

Upon completion, contains() on this collection will return false for all elements in the supplied collection.

Parameters:
 vCol the collection of elements to remove
Returns:
true iff this collection was modified as a result of this operation
Exceptions:
 coherence::lang::NullPointerException if the specified collection is NULL
See also:
remove()

contains()

virtual bool retainAll (Collection::View vc)
 Remove all elements from this collection that are not present in the supplied collection.

Parameters:
 vCol the collection of elements to retain
Returns:
true iff this collection was modified as a result of this operation.
Exceptions:
 coherence::lang::NullPointerException if the specified collection is NULL
See also:
remove()

contains()

virtual void clear ()
 Remove all elements from this collection.
virtual void toStream (std::ostream &out) const
 Output a human-readable description of this Object to the given stream.

coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toStream method, to output Objects. If a managed String object is desired, the COH_TO_STRING macro can be used to build up a String from streamable contents.

 Object::View vKey   = ...
 Object::View vValue = ...
 std::cout << vKey << " = " << vValue << std::endl;

 String::Handle hs = COH_TO_STRING(vKey << " = " << vValue);

Parameters:
 out the stream used to output the description
virtual size32_t hashCode () const
 Return a hash code value for the Object.

This method is supported for the benefit of hash-based containers.

The general contract of hashCode is:

  • Whenever it is invoked on the same Object more than once during an execution of an application, the hashCode method must consistently return the same value, provided no information used in equals comparisons on the object is modified. This value need not remain consistent from one execution of an application to another execution of the same application.
  • If two Objects are equal according to the equals method, then calling the hashCode method on each of the two Objects must produce the same value.
  • It is not required that if two Objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct results. However, the programmer should be aware that producing distinct results for unequal objects may improve the performance of hash-based containers.

The default implementation is identity based.

Returns:
a hash code value for this Object
virtual bool equals (Object::View v) const
  
virtual bool isImmutable () const
 Return true iff no further changes can be made to the Object, that would effect the outcome of a call to its equals method.

Except for Objects which are naturally immutable (such as String), being immutable generally implies that the Object is only referenced via const pointers or views. Objects which hold references to child Objects, may need to take the immutability of their children into account when determining their own immutability.

This extended check is not performed by the default implementation, but can be integrated into the immutability checks by overriding this method, as well as making use of MemberHandles to reference child Objects.

A typical derived implementation may look as follows:

 bool isImmutable() const
     {
     if (m_fImmutable) // check recorded state
         {
         return true; // already marked as immutable, avoid calculation
         }
     else if (Object::isImmutable()) // ensure shallow immutability
         {
         // ensure deep immutability
         if (m_child1->isImmutable() && m_child2->isImmutable() ...
                                     && m_childN->isImmutable())
             {
             // record and return immutability
             return m_fImmutable = true;
             }
         // some Objects which comprise this Object are still mutable
         }
     return false;
     }
 

The default implementation return true iff the Object is only referenced via const pointers and or views.

Returns:
true iff the Object is immutable

Protected Member Functions

 AbstractWrapperCollection (Collection::Holder ohCollDelegate)
 Create an AbstractWrapperCollection which delegates to the specified Collection.
 AbstractWrapperCollection (const AbstractWrapperCollection &that)
 Copy constructor.
virtual
Collection::Handle 
getDelegate ()
 Return a handle to the delegate.
virtual Collection::View getDelegate () const
 Return a view to the delegate.

Constructor & Destructor Documentation

AbstractWrapperCollection ( Collection::Holder  ohCollDelegate  )  [protected]

Create an AbstractWrapperCollection which delegates to the specified Collection.

Parameters:
 ohCollDelegate the Collection to delegate to


Member Function Documentation

virtual Collection::Handle getDelegate (  )  [protected, virtual]

Return a handle to the delegate.

Returns:
the delegate handle
Exceptions:
 UnsupportedOperationException if the delegate is a view

virtual Collection::View getDelegate (  )  const [protected, virtual]

Return a view to the delegate.

Returns:
the delegate view


The documentation for this class was generated from the following file:
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