Oracle Coherence for C++ API


IdentityExtractor Class Reference

#include <coherence/util/extractor/IdentityExtractor.hpp>

Inherits AbstractExtractor.

List of all members.

Detailed Description

Trivial ValueExtractor implementation that does not actually extract anything from the passed value, but returns the value itself.
djl 2008.03.05

Public Types

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

Public Member Functions

virtual Object::Holder  extract (Object::Holder ohTarget) const
  Extract the value from the passed object.

The returned value may be NULL.

ohTarget  an Object to retrieve the value from
the extracted value; NULL is an acceptable value
ClassCastException  if this ValueExtractor is incompatible with the passed object to extract a value from and the implementation requires the passed object to be of a certain type
Exception  if this ValueExtractor encounters an exception in the course of extracting the value
IllegalArgumentException  if this ValueExtractor cannot handle the passed object for any other reason; an implementor should include a descriptive message

virtual void  readExternal (PofReader::Handle hIn)
virtual void  writeExternal (PofWriter::Handle hOut) const
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 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);
out  the stream used to output the description

Static Public Member Functions

getInstance ()
  An instance of the IdentityExtractor.

Protected Member Functions

  IdentityExtractor ()
  Create and return a Handle to a new Object instance.

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