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NoElements Class Reference

#include <NoElements.h>

Inheritance diagram for NoElements:

List of all members.

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Detailed Description

NoElements: signals a failed attempt to extract an element.

Raise a NoElements exception if an attempt is made to extract an element from an empty Collection. Similar dispensing containers may also raise this exception. NoElements provides access to the failed object(), the error message(), the failed method() and a default element(). Typically, a NoElements exception indicates a semantic failure in a program which tried to retrieve more elements than it stored, so is treated as fatal. However, certain dispensing programs may wish to recover. These should supply a default element when the NoElements exception is raised. This element may be cloned during recovery and used in place of the missing element.

Public Member Functions
	NoElements ()
	Construct a default NoElements.
virtual	~NoElements ()
	Release a NoElements.
	NoElements (ObjectID, StringID)
	Construct a NoElements exception.
	NoElements (ObjectID, StringID, ObjectID)
	Construct a NoElements exception, supplying a default element.
virtual ObjectID	clone () const
	Clone a shallow copy of this NoElements.
ObjectID	element () const
	Access the default element.
Protected Member Functions
	NoElements (const NoElements &)
	Copy another NoElements.
Protected Attributes
ObjectID	defaultElement
	A default element, or null.

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Constructor & Destructor Documentation

NoElements::NoElements (  const NoElements &  exception  )  [protected]

Copy another NoElements. Required by C++ to ensure that copying an NoElements faithfully copies a MethodError. Parameters: exception  - the NoElements to copy. Returns: a NoElements, a shallow copy.

NoElements::NoElements (   )

Construct a default NoElements. Returns: a NoElements

NoElements::~NoElements (   )  [virtual]

Release a NoElements.

NoElements::NoElements (  ObjectID  object, StringID  method )

Construct a NoElements exception. Raised when an attempt is made to access an element of an empty Collection. May also be raised by other kinds of dispensing container, when they run out of elements. The default element is set to null. Parameters: object  - the object on which element access failed. method  - the name of the failed method. Returns: a NoElements exception.

NoElements::NoElements (  ObjectID  object, StringID  method, ObjectID  element )

Construct a NoElements exception, supplying a default element. Raised when an attempt is made to access an element from a fail-safe dispensing container, when this becomes empty. During recovery, the default element may be used directly, or cloned by the program. Parameters: object  - the object on which element access failed. method  - the name of the failed method. element  - a default element to use instead. Returns: a NoElements exception.

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Member Function Documentation

ObjectID NoElements::clone (   )  const [virtual]

Clone a shallow copy of this NoElements. Returns: a NoElements exception, a shallow copy. Reimplemented from Exception.

ObjectID NoElements::element (   )  const [inline]

Access the default element. Returns: the default element.

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Member Data Documentation

ObjectID NoElements::defaultElement [protected]

A default element, or null.

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

• NoElements.h
• NoElements.cc

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