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CMemCache

Package system.caching
Inheritance class CMemCache » CCache » CApplicationComponent » CComponent
Implements ArrayAccess, ICache, IApplicationComponent
Since 1.0
Version $Id: CMemCache.php 1456 2009-10-15 20:32:08Z qiang.xue $
CMemCache implements a cache application component based on memcached.

CMemCache can be configured with a list of memcache servers by settings its servers property. By default, CMemCache assumes there is a memcache server running on localhost at port 11211.

See CCache manual for common cache operations that are supported by CMemCache.

Note, there is no security measure to protected data in memcache. All data in memcache can be accessed by any process running in the system.

To use CMemCache as the cache application component, configure the application as follows,
array(
    'components'=>array(
        'cache'=>array(
            'class'=>'CMemCache',
            'servers'=>array(
                array(
                    'host'=>'server1',
                    'port'=>11211,
                    'weight'=>60,
                ),
                array(
                    'host'=>'server2',
                    'port'=>11211,
                    'weight'=>40,
                ),
            ),
        ),
    ),
)
In the above, two memcache servers are used: server1 and server2. You can configure more properties of every server, including: host, port, persistent, weight, timeout, retryInterval, status. See http://www.php.net/manual/en/function.memcache-addserver.php for more details.

Since version 1.0.6, CMemCache can also be used with memcached. To do so, set useMemcached to be true.

Public Properties

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PropertyTypeDescriptionDefined By
behaviors array the behaviors that should be attached to this component. CApplicationComponent
isInitialized boolean whether this application component has been initialized (i. CApplicationComponent
keyPrefix string a string prefixed to every cache key so that it is unique. CCache
memCache mixed the memcache instance (or memcached if useMemcached is true) used by this component. CMemCache
servers array list of memcache server configurations. CMemCache
useMemcached boolean whether to use {@link http://pecl. CMemCache

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. CCache
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 CCache
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
flush() Deletes all values from cache. CMemCache
get() Retrieves a value from cache with a specified key. CCache
getEventHandlers() Returns the list of attached event handlers for an event. CComponent
getIsInitialized() CApplicationComponent
getMemCache() CMemCache
getServers() CMemCache
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 this application component. CMemCache
mget() Retrieves multiple values from cache with the specified keys. CCache
offsetExists() Returns whether there is a cache entry with a specified key. CCache
offsetGet() Retrieves the value from cache with a specified key. CCache
offsetSet() Stores the value identified by a key into cache. CCache
offsetUnset() Deletes the value with the specified key from cache CCache
raiseEvent() Raises an event. CComponent
set() Stores a value identified by a key into cache. CCache
setServers() CMemCache

Protected Methods

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MethodDescriptionDefined By
addValue() Stores a value identified by a key into cache if the cache does not contain this key. CMemCache
deleteValue() Deletes a value with the specified key from cache CMemCache
generateUniqueKey() CCache
getValue() Retrieves a value from cache with a specified key. CMemCache
getValues() Retrieves multiple values from cache with the specified keys. CMemCache
setValue() Stores a value identified by a key in cache. CMemCache

Property Details

memCache property read-only
public mixed getMemCache()

the memcache instance (or memcached if useMemcached is true) used by this component.

servers property
public array getServers()
public void setServers(array $config)

list of memcache server configurations. Each element is a CMemCacheServerConfiguration.

useMemcached property (available since v1.0.6)
public boolean $useMemcached;

whether to use memcached as the underlying caching extension. Defaults to false, meaning using memcache.

Method Details

addValue() method
protected boolean addValue(string $key, string $value, integer $expire)
$key string the key identifying the value to be cached
$value string the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
{return} boolean true if the value is successfully stored into cache, false otherwise

Stores a value identified by a key into cache if the cache does not contain this key. This is the implementation of the method declared in the parent class.

deleteValue() method
protected boolean deleteValue(string $key)
$key string the key of the value to be deleted
{return} boolean if no error happens during deletion

Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.

flush() method
public void flush()

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

getMemCache() method
public mixed getMemCache()
{return} mixed the memcache instance (or memcached if useMemcached is true) used by this component.

getServers() method
public array getServers()
{return} array list of memcache server configurations. Each element is a CMemCacheServerConfiguration.

getValue() method
protected string getValue(string $key)
$key string a unique key identifying the cached value
{return} string the value stored in cache, false if the value is not in the cache or expired.

Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class.

getValues() method (available since v1.0.8)
protected array getValues(array $keys)
$keys array a list of keys identifying the cached values
{return} array a list of cached values indexed by the keys

Retrieves multiple values from cache with the specified keys.

init() method
public void init()

Initializes this application component. This method is required by the IApplicationComponent interface. It creates the memcache instance and adds memcache servers.

setServers() method
public void setServers(array $config)
$config array list of memcache server configurations. Each element must be an array with the following keys: host, port, persistent, weight, timeout, retryInterval, status.

setValue() method
protected boolean setValue(string $key, string $value, integer $expire)
$key string the key identifying the value to be cached
$value string the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
{return} boolean true if the value is successfully stored into cache, false otherwise

Stores a value identified by a key in cache. This is the implementation of the method declared in the parent class.

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