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CQueue

Package system.collections
Inheritance class CQueue » CComponent
Implements IteratorAggregate, Countable, Traversable
Since 1.0
Source Code framework/collections/CQueue.php
CQueue implements a queue.

The typical queue operations are implemented, which include enqueue(), dequeue() and peek(). In addition, contains() can be used to check if an item is contained in the queue. To obtain the number of the items in the queue, check the Count property.

Items in the queue may be traversed using foreach as follows, 
 foreach($queue as $item) ...

Public Properties

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PropertyTypeDescriptionDefined By
count integer Returns the number of items in the queue. CQueue
iterator Iterator Returns an iterator for traversing the items in the queue. CQueue

Public Methods

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MethodDescriptionDefined By
__call() Calls the named method which is not a class method. CComponent
__construct() Constructor. CQueue
__get() Returns a property value, an event handler list or a behavior based on its name. CComponent
__isset() Checks if a property value is null. CComponent
__set() Sets value of a component property. CComponent
__unset() Sets a component property to be null. CComponent
asa() Returns the named behavior object. CComponent
attachBehavior() Attaches a behavior to this component. CComponent
attachBehaviors() Attaches a list of behaviors to the component. CComponent
attachEventHandler() Attaches an event handler to an event. CComponent
canGetProperty() Determines whether a property can be read. CComponent
canSetProperty() Determines whether a property can be set. CComponent
clear() Removes all items in the queue. CQueue
contains() CQueue
copyFrom() Copies iterable data into the queue. CQueue
count() Returns the number of items in the queue. CQueue
dequeue() Removes and returns the object at the beginning of the queue. CQueue
detachBehavior() Detaches a behavior from the component. CComponent
detachBehaviors() Detaches all behaviors from the component. CComponent
detachEventHandler() Detaches an existing event handler. CComponent
disableBehavior() Disables an attached behavior. CComponent
disableBehaviors() Disables all behaviors attached to this component. CComponent
enableBehavior() Enables an attached behavior. CComponent
enableBehaviors() Enables all behaviors attached to this component. CComponent
enqueue() Adds an object to the end of the queue. CQueue
evaluateExpression() Evaluates a PHP expression or callback under the context of this component. CComponent
getCount() Returns the number of items in the queue. CQueue
getEventHandlers() Returns the list of attached event handlers for an event. CComponent
getIterator() Returns an iterator for traversing the items in the queue. CQueue
hasEvent() Determines whether an event is defined. CComponent
hasEventHandler() Checks whether the named event has attached handlers. CComponent
hasProperty() Determines whether a property is defined. CComponent
peek() Returns the item at the top of the queue. CQueue
raiseEvent() Raises an event. CComponent
toArray() CQueue

Property Details

count property read-only
public integer getCount()

Returns the number of items in the queue.

iterator property read-only
public Iterator getIterator()

Returns an iterator for traversing the items in the queue. This method is required by the interface IteratorAggregate.

Method Details

__construct() method
public void __construct(array $data=NULL)
$data array the initial data. Default is null, meaning no initialization.
Source Code: framework/collections/CQueue.php#51 (show)
public function __construct($data=null)
{
    if($data!==null)
        $this->copyFrom($data);
}

Constructor. Initializes the queue with an array or an iterable object.

clear() method
public void clear()
Source Code: framework/collections/CQueue.php#89 (show)
public function clear()
{
    $this->_c=0;
    $this->_d=array();
}

Removes all items in the queue.

contains() method
public boolean contains(mixed $item)
$item mixed the item
{return} boolean whether the queue contains the item
Source Code: framework/collections/CQueue.php#99 (show)
public function contains($item)
{
    return array_search($item,$this->_d,true)!==false;
}

copyFrom() method
public void copyFrom(mixed $data)
$data mixed the data to be copied from, must be an array or object implementing Traversable
Source Code: framework/collections/CQueue.php#71 (show)
public function copyFrom($data)
{
    if(is_array($data) || ($data instanceof Traversable))
    {
        $this->clear();
        foreach($data as $item)
        {
            $this->_d[]=$item;
            ++$this->_c;
        }
    }
    elseif($data!==null)
        throw new CException(Yii::t('yii','Queue data must be an array or an object implementing Traversable.'));
}

Copies iterable data into the queue. Note, existing data in the list will be cleared first.

count() method
public integer count()
{return} integer number of items in the queue.
Source Code: framework/collections/CQueue.php#169 (show)
public function count()
{
    return $this->getCount();
}

Returns the number of items in the queue. This method is required by Countable interface.

dequeue() method
public mixed dequeue()
{return} mixed the item at the beginning of the queue
Source Code: framework/collections/CQueue.php#122 (show)
public function dequeue()
{
    if($this->_c===0)
        throw new CException(Yii::t('yii','The queue is empty.'));
    else
    {
        --$this->_c;
        return array_shift($this->_d);
    }
}

Removes and returns the object at the beginning of the queue.

enqueue() method
public void enqueue(mixed $item)
$item mixed the item to be appended into the queue
Source Code: framework/collections/CQueue.php#137 (show)
public function enqueue($item)
{
    ++$this->_c;
    $this->_d[]=$item;
}

Adds an object to the end of the queue.

getCount() method
public integer getCount()
{return} integer the number of items in the queue
Source Code: framework/collections/CQueue.php#158 (show)
public function getCount()
{
    return $this->_c;
}

Returns the number of items in the queue.

getIterator() method
public Iterator getIterator()
{return} Iterator an iterator for traversing the items in the queue.
Source Code: framework/collections/CQueue.php#149 (show)
public function getIterator()
{
    return new CQueueIterator($this->_d);
}

Returns an iterator for traversing the items in the queue. This method is required by the interface IteratorAggregate.

peek() method
public mixed peek()
{return} mixed item at the top of the queue
Source Code: framework/collections/CQueue.php#109 (show)
public function peek()
{
    if($this->_c===0)
        throw new CException(Yii::t('yii','The queue is empty.'));
    else
        return $this->_d[0];
}

Returns the item at the top of the queue.

toArray() method
public array toArray()
{return} array the list of items in queue
Source Code: framework/collections/CQueue.php#60 (show)
public function toArray()
{
    return $this->_d;
}