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CDummyCache

Package system.caching
Inheritance class CDummyCache » CApplicationComponent » CComponent
Implements IApplicationComponent, ICache, ArrayAccess
Since 1.0
Source Code framework/caching/CDummyCache.php
CDummyCache is a placeholder cache component.

CDummyCache does not cache anything. It is provided so that one can always configure a 'cache' application component and he does not need to check if Yii::app()->cache is null or not. By replacing CDummyCache with some other cache component, one can quickly switch from non-caching mode to caching mode.

Public Properties

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PropertyTypeDescriptionDefined By
behaviors array the behaviors that should be attached to this component. CApplicationComponent
isInitialized boolean Checks if this application component has been initialized. CApplicationComponent
keyPrefix string a string prefixed to every cache key so that it is unique. CDummyCache

Public Methods

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MethodDescriptionDefined By
__call() Calls the named method which is not a class method. CComponent
__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
add() Stores a value identified by a key into cache if the cache does not contain this key. CDummyCache
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
delete() Deletes a value with the specified key from cache CDummyCache
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
evaluateExpression() Evaluates a PHP expression or callback under the context of this component. CComponent
flush() Deletes all values from cache. CDummyCache
get() Retrieves a value from cache with a specified key. CDummyCache
getEventHandlers() Returns the list of attached event handlers for an event. CComponent
getIsInitialized() Checks if this application component has been initialized. CApplicationComponent
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
init() Initializes the application component. CDummyCache
mget() Retrieves multiple values from cache with the specified keys. CDummyCache
offsetExists() Returns whether there is a cache entry with a specified key. CDummyCache
offsetGet() Retrieves the value from cache with a specified key. CDummyCache
offsetSet() Stores the value identified by a key into cache. CDummyCache
offsetUnset() Deletes the value with the specified key from cache CDummyCache
raiseEvent() Raises an event. CComponent
set() Stores a value identified by a key into cache. CDummyCache

Property Details

keyPrefix property
public string $keyPrefix;

a string prefixed to every cache key so that it is unique. Defaults to application ID.

Method Details

add() method
public boolean add(string $id, mixed $value, integer $expire=0, ICacheDependency $dependency=NULL)
$id string the key identifying the value to be cached
$value mixed the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
$dependency ICacheDependency dependency of the cached item. If the dependency changes, the item is labeled invalid.
{return} boolean true if the value is successfully stored into cache, false otherwise
Source Code: framework/caching/CDummyCache.php#94 (show)
public function add($id,$value,$expire=0,$dependency=null)
{
    return 
true;
}

Stores a value identified by a key into cache if the cache does not contain this key. Nothing will be done if the cache already contains the key.

delete() method
public boolean delete(string $id)
$id string the key of the value to be deleted
{return} boolean if no error happens during deletion
Source Code: framework/caching/CDummyCache.php#104 (show)
public function delete($id)
{
    return 
true;
}

Deletes a value with the specified key from cache

flush() method
public boolean flush()
{return} boolean whether the flush operation was successful.
Source Code: framework/caching/CDummyCache.php#115 (show)
public function flush()
{
    return 
true;
}

Deletes all values from cache. Be careful of performing this operation if the cache is shared by multiple applications.

get() method
public mixed get(string $id)
$id string a key identifying the cached value
{return} mixed the value stored in cache, false if the value is not in the cache, expired or the dependency has changed.
Source Code: framework/caching/CDummyCache.php#46 (show)
public function get($id)
{
    return 
false;
}

Retrieves a value from cache with a specified key.

init() method
public void init()
Source Code: framework/caching/CDummyCache.php#34 (show)
public function init()
{
    
parent::init();
    if(
$this->keyPrefix===null)
        
$this->keyPrefix=Yii::app()->getId();
}

Initializes the application component. This method overrides the parent implementation by setting default cache key prefix.

mget() method
public array mget(array $ids)
$ids array list of keys identifying the cached values
{return} array list of cached values corresponding to the specified keys. The array is returned in terms of (key,value) pairs. If a value is not cached or expired, the corresponding array value will be false.
Source Code: framework/caching/CDummyCache.php#61 (show)
public function mget($ids)
{
    
$results=array();
    foreach(
$ids as $id)
        
$results[$id]=false;
    return 
$results;
}

Retrieves multiple values from cache with the specified keys. Some caches (such as memcache, apc) allow retrieving multiple cached values at one time, which may improve the performance since it reduces the communication cost. In case a cache doesn't support this feature natively, it will be simulated by this method.

offsetExists() method
public boolean offsetExists(string $id)
$id string a key identifying the cached value
{return} boolean
Source Code: framework/caching/CDummyCache.php#126 (show)
public function offsetExists($id)
{
    return 
false;
}

Returns whether there is a cache entry with a specified key. This method is required by the interface ArrayAccess.

offsetGet() method
public mixed offsetGet(string $id)
$id string a key identifying the cached value
{return} mixed the value stored in cache, false if the value is not in the cache or expired.
Source Code: framework/caching/CDummyCache.php#137 (show)
public function offsetGet($id)
{
    return 
false;
}

Retrieves the value from cache with a specified key. This method is required by the interface ArrayAccess.

offsetSet() method
public void offsetSet(string $id, mixed $value)
$id string the key identifying the value to be cached
$value mixed the value to be cached
Source Code: framework/caching/CDummyCache.php#150 (show)
public function offsetSet($id$value)
{
}

Stores the value identified by a key into cache. If the cache already contains such a key, the existing value will be replaced with the new ones. To add expiration and dependencies, use the set() method. This method is required by the interface ArrayAccess.

offsetUnset() method
public boolean offsetUnset(string $id)
$id string the key of the value to be deleted
{return} boolean if no error happens during deletion
Source Code: framework/caching/CDummyCache.php#160 (show)
public function offsetUnset($id)
{
}

Deletes the value with the specified key from cache This method is required by the interface ArrayAccess.

set() method
public boolean set(string $id, mixed $value, integer $expire=0, ICacheDependency $dependency=NULL)
$id string the key identifying the value to be cached
$value mixed the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
$dependency ICacheDependency dependency of the cached item. If the dependency changes, the item is labeled invalid.
{return} boolean true if the value is successfully stored into cache, false otherwise
Source Code: framework/caching/CDummyCache.php#80 (show)
public function set($id,$value,$expire=0,$dependency=null)
{
    return 
true;
}

Stores a value identified by a key into cache. If the cache already contains such a key, the existing value and expiration time will be replaced with the new ones.

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