Oracle Coherence for C++ API
Release 3.6.1.0

E18813-01

WrapperCollections::AbstractWrapperMap Class Reference

#include <coherence/util/WrapperCollections.hpp>

Inherits Object, and Map.

Inherited by ConverterCollections::ConverterMap, and TypedCollections::TypedMap.

List of all members.


Detailed Description

Map implementation which delegates all calls to another Map.

Public Types

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

Public Member Functions

virtual size32_t  size () const
  Return the number of key-value mappings in this map.
Returns:
the number of key-value mappings in this map.

virtual bool  isEmpty () const
  Return true if this map contains no key-value mappings.
Returns:
true if this map contains no key-value mappings.

virtual bool  containsKey (Object::View vKey) const
  Return true if this map contains a mapping for the specified key.
Parameters:
vKey  key whose presence in this map is to be tested.
Returns:
true if this map contains a mapping for the specified key.

virtual bool  containsValue (Object::View vValue) const
  Return true if this map maps one or more keys to the specified value.

This operation will probably require time linear in the map size for most implementations of the Map interface.

Parameters:
vValue  value whose presence in this map is to be tested.
Returns:
true if this map maps one or more keys to the specified value.

virtual Object::Holder  get (Object::View vKey) const
  Return the value to which this map maps the specified key.

Return NULL if the map contains no mapping for this key. A return value of NULL does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to NULL. The containsKey operation may be used to distinguish these two cases.

Parameters:
vKey  key whose associated value is to be returned.
Returns:
the value to which this map maps the specified key, or NULL if the map contains no mapping for this key.
See also:
containsKey()

virtual Object::Holder  get (Object::View vKey)
  Return the value to which this map maps the specified key.

Return NULL if the map contains no mapping for this key. A return value of NULL does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to NULL. The containsKey operation may be used to distinguish these two cases.

Parameters:
vKey  key whose associated value is to be returned.
Returns:
the value to which this map maps the specified key, or NULL if the map contains no mapping for this key.
See also:
containsKey()

virtual Object::Holder  put (Object::View vKey, Object::Holder ohValue)
  Associate the specified value with the specified key in this map.

If the map previously contained a mapping for this key, the old value is replaced by the specified value.

Parameters:
vKey  key with which the specified value is to be associated.
ohValue  value to be associated with the specified key.
Returns:
previous value associated with specified key, or NULL if there was no mapping for key. A NULL return can also indicate that the map previously associated NULL with the specified key.
Exceptions:
coherence::lang::UnsupportedOperationException  if the put() operation is not supported by this map.

virtual Object::Holder  remove (Object::View vKey)
  Remove the mapping for this key from this map if it is present.

Return the value to which the map previously associated the key, or NULL if the map contained no mapping for this key. (A NULL return can also indicate that the map previously associated NULL with the specified key.) The map will not contain a mapping for the specified key once the call returns.

Parameters:
vKey  key whose mapping is to be removed from the map.
Returns:
previous value associated with specified key, or NULL if there was no mapping for key.
Exceptions:
coherence::lang::UnsupportedOperationException  if the remove() operation is not supported by this map.

virtual void  putAll (Map::View vMap)
  Copy all of the mappings from the specified map to this map.

The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map. The behavior of this operation is unspecified if the specified map is modified while the operation is in progress.

Parameters:
vMap  mappings to be stored in this map.
Exceptions:
coherence::lang::UnsupportedOperationException  if the put() operation is not supported by this map.

virtual void  clear ()
  Remove all mappings from this map.
Exceptions:
coherence::lang::UnsupportedOperationException  if the clear()operation is not supported by this map.

virtual Set::View  keySet () const
  Return a set of the keys contained in this map.

The set is backed by the map, so changes to the map are reflected in the set. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

Returns:
a set of the keys contained in this map.

virtual Set::Handle  keySet ()
  Return a set of the keys contained in this map.

The set is backed by the map, so changes to one are reflected in the other. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

Returns:
a set of the keys contained in this map.

virtual Collection::View  values () const
  Return a collection of the values contained in this map.

The collection is backed by the map, so changes to the map are reflected in the set. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined.

Returns:
a collection of the values contained in this map.

virtual
Collection::Handle 
values ()
  Return a collection of the values contained in this map.

The collection is backed by the map, so changes to one are reflected in the other. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined.

Returns:
a collection of the values contained in this map.

virtual Set::View  entrySet () const
  Return a set of the mappings contained in this map.

Each element in the returned set is a Map::Entry::View. The set is backed by the map, so changes to the map are reflected in the set. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

Returns:
a set of the mappings contained in this map.

virtual Set::Handle  entrySet ()
  Return a set of the mappings contained in this map.

Each element in the returned set is a Map::Entry::Handle. The set is backed by the map, so changes to one are reflected in the other. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

Returns:
a set of the mappings contained in this map.

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

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

Constructor & Destructor Documentation

AbstractWrapperMap ( Map::Holder  ohMapDelegate  )  [protected]

Create an AbstractWrapperMap which delegates to the specified Map.

Parameters:
ohMapDelegate  the Map to delegate to

Member Function Documentation

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

Return a handle to the delegate.

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

virtual Map::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:
Copyright © 2000, 2010, Oracle and/or its affiliates. All rights reserved.