Oracle Coherence for C++ API


Binary Class Reference

#include <coherence/util/Binary.hpp>

Inherits OctetArrayReadBuffer.

List of all members.

Detailed Description

A thread-safe immutable binary object.

jh 2008.05.29

Public Types

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

Public Member Functions

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 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.

true iff the Object is immutable

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

Protected Member Functions

virtual void updateLength (size32_t cb)
 Allow the length to be modified.

This method is provided for use by OctetArrayWriteBuffer only, and only for read buffers that it owns.

cb the new length

virtual ReadBuffer::View instantiateReadBuffer (size32_t of, size32_t cb) const
 Factory method: Instantiate a ReadBuffer for a portion of this ReadBuffer.

of the beginning index, inclusive
cb the number of bytes to include in the resulting ReadBuffer
a ReadBuffer that represents a portion of this ReadBuffer

The documentation for this class was generated from the following file:
Copyright © 2000, 2011, Oracle and/or its affiliates. All rights reserved.