container::Queue Class Reference

Abstract base class for all queue containers. More...

#include <queue.h>

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List of all members.

Public Member Functions
virtual	~Queue ()
void	enqueue (Entity *entity)
	Add an Entity onto the end of the Queue.
Entity *	dequeue ()
	Remove the first Entity from the Queue and return a pointer to the Entity.
int	purgeContents ()
	Empty the contents of the container, deleting all Entities.
virtual ostream &	renderState (ostream &os) const
	Write the state of an Object for debugging and demonstration.
virtual const Info *	typeInfo () const
	Return the instance of Object::Info that describes the class of this object.
virtual Object *	clone (bool deepCopy=false) const =0
	A polymorphic copy constructor.
Static Public Attributes
static const Info *const	TYPE_INFO = Object::typeInfoFactory("Queue")
Protected Member Functions
	Queue ()
	Queue (const Queue &orig)
virtual void	enqueue_impl (Entity *entity)=0
	Called by a template method.
virtual Entity *	dequeue_impl ()=0
	Called by a template method.
Private Member Functions
void	setCount (int c)
	Hide from sub-classes.
void	incCount ()
	Hide from sub-classes.
void	decCount ()
	Hide from sub-classes.

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Detailed Description

Abstract base class for all queue containers.

Allows duplicates. Is unbounded.

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Constructor & Destructor Documentation

container::Queue::Queue

(

)

[protected]

{ }

container::Queue::Queue

(

const Queue &

orig

)

[protected]

: Container(orig) { }

container::Queue::~Queue

(

)

[virtual]

{ }

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Member Function Documentation

virtual Object* container::Queue::clone

(

bool

deepCopy = false

)

const [pure virtual]

A polymorphic copy constructor.

Implements container::Container.

Implemented in container::QueueImpl.

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void container::Queue::decCount

(

)

[inline, private]

Hide from sub-classes.

Reimplemented from container::Container.

                          {
      Container::decCount();
   }

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Entity * container::Queue::dequeue

(

)

Remove the first Entity from the Queue and return a pointer to the Entity.

A template method that calls the dequeue_impl method of the the derived class.

Returns:

A pointer to the Entity that was removed from the first position of the queue

Precondition:

There is at least one item in the Queue

Postcondition:

The Entity (formerly the first item) is not in the list

The caller is responsible for deleting the extracted Entity

The Container's count is lesser by one

If the Queue had 2 or more items, then the formerly 2nd Entity is the first item

If the Queue had only 1 item, then the Queue is empty

                        {
   if (getCount() == 0) {
      return NULL;
   }
   Entity * e = dequeue_impl();
   decCount();
   return e;
}

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virtual Entity* container::Queue::dequeue_impl

(

)

[protected, pure virtual]

Called by a template method.

See also:

Details documented in method dequeue

Implemented in container::QueueImpl.

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void container::Queue::enqueue

(

Entity *

entity

)

Add an Entity onto the end of the Queue.

A template method that calls the enqueue_impl method of the the derived class.

Precondition:

The specified entity pointer is not null

Postcondition:

If there were already 1 or more items in the queue, the specified entity is the last item in the Queue

If the queue was empty, the specified entity can be considered to be both the first and last item in the queue

The Container's count is greater by one

                                  {
   if (entity == NULL) {
      return;
   }
   enqueue_impl(entity);
   incCount();
}

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virtual void container::Queue::enqueue_impl

(

Entity *

entity

)

[protected, pure virtual]

Called by a template method.

See also:

Details documented in method enqueue

Implemented in container::QueueImpl.

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void container::Queue::incCount

(

)

[inline, private]

Hide from sub-classes.

Reimplemented from container::Container.

                          {
      Container::incCount();
   }

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int container::Queue::purgeContents

(

)

[virtual]

Empty the contents of the container, deleting all Entities.

This method is used by the destructor.

Returns:

The number of Entity objects deleted

Postcondition:

isEmpty() is true

The memory for all Entities is freed

Implements container::Container.

                         {
   int n = 0;
   for (Entity* e = dequeue(); e != NULL; e = dequeue()) {
      delete e;
      n++;
   }
   return n;
}

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ostream & container::Queue::renderState

(

ostream &

os

)

const [virtual]

Write the state of an Object for debugging and demonstration.

This method must not change the state of an Object; adding or removing debug statements should not change the behavior of a class. The implementation must be robust, e.g., NULL safe, etc. and work without an unrecoverable error for any state, excluding an Object's time of construction and destruction. It is not required for the implementation to be thread safe.

Precondition:

The Object has been fully constructed and is not in the process of destruction

Postcondition:

The state of the Object is unchanged

Reimplemented from container::Container.

Reimplemented in container::QueueImpl.

                                              {
   return this->Container::renderState(os);
}

void container::Queue::setCount

(

int

c

)

[inline, private]

Hide from sub-classes.

Reimplemented from container::Container.

                               {
      Container::setCount(c);
   }

const Object::Info * container::Queue::typeInfo

(

)

const [virtual]

Return the instance of Object::Info that describes the class of this object.

Instantiation of Object::Info is controlled by the protected method Object::typeInfoFactory(const string&). Each sub-class of Object should create one and only one instance of Object::Info.

Reimplemented from container::Container.

Reimplemented in container::QueueImpl.

                                        {
   return TYPE_INFO;
}

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Member Data Documentation

const Object::Info *const container::Queue::TYPE_INFO = Object::typeInfoFactory("Queue") [static]

Reimplemented from container::Container.

Reimplemented in container::QueueImpl.

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

• queue.h
• queue.cpp