Chain

Multi-backend chained cache backend.

class Chain extends \Hazaar\Cache\Backend

Extends: Hazaar\Cache\Backend

Composes multiple cache backends to provide fallback behavior and redundancy. Backend instances are ordered by weight, allowing reads to prefer faster backends and repopulate slower/missed layers when a hit is found downstream.

Configuration expects a backends map where keys are backend names and values are backend-specific option arrays.

Properties

backends

private array $backends

Type: array

order

private array $order

Type: array

Methods

available

Indicates that the chain backend is always available.

public available(): bool

Returns: bool

init

Initializes and orders configured backend chain members.

public init(string $namespace): void

Returns: void

Parameters

Parameter	Type	Description
$namespace	string	namespace passed to each backend instance

close

Closes all cache backend connections in the chain.

public close(): bool

Returns: bool

Iterates through each backend and calls its close() method.

has

Checks whether any backend in the chain contains the key.

public has(string $key, bool $checkEmpty): bool

Returns: bool

Parameters

Parameter	Type	Description
$key	string	cache key
$checkEmpty	bool	whether to treat empty values as missing

get

Retrieves a value from the backend chain by weighted order.

public get(string $key): mixed

Returns: mixed

On hit from a lower-priority backend, missed higher-priority backends are repopulated with the discovered value.

Parameters

Parameter	Type	Description
$key	string	cache key

set

Stores a value in all configured backends.

public set(string $key, mixed $value, int $timeout): bool

Returns: bool

Parameters

Parameter	Type	Description
$key	string	cache key
$value	mixed	value to store
$timeout	int	TTL in seconds

remove

Removes a key from all configured backends.

public remove(string $key): bool

Returns: bool

Parameters

Parameter	Type	Description
$key	string	cache key

clear

Clears all configured backends.

public clear(): bool

Returns: bool

setExpireTimeout

Updates expire timeout option across all configured backends.

public setExpireTimeout(int $timeout): void

Returns: void

Parameters

Parameter	Type	Description
$timeout	int	expire timeout in seconds

toArray

Returns all cached values from the first backend in the chain.

public toArray(): array

Returns: array

count

Returns key count from the first backend in the chain.

public count(): int

Returns: int

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Generated by Hazaar API Doc Generator on Fri, 04 Sep 2026 23:32:16 +0000