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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