Oracle Coherence for C++ API


AbstractList Class Reference

#include <coherence/util/AbstractList.hpp>

Inherits AbstractCollection, and List.

Inherited by CircularArrayList, LinkedList, ReadOnlyMultiList, and SubList.

List of all members.

Detailed Description

This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface.

Public Types

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

Public Member Functions

virtual Object::Holder get (size32_t i)
 Return the element from the specified position in the list.

i the position of the item to return
the element from the specified position in the list
coherence::lang::IndexOutOfBoundsException if the index is out of range

virtual bool equals (Object::View v) const
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.

a hash code value for this Object

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.

true iff the Object is immutable

Protected Attributes

size32_t m_nHashCode
 The cached hash of all the array elements.

Member Data Documentation

size32_t m_nHashCode [mutable, protected]

The cached hash of all the array elements.

The hash code is not cached until the List becomes immutable. A value of 0 indicates that the has has not been cached.

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