Chain

Multi-backend chained cache backend.

class Chain extends \Hazaar\Cache\Backend\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

order

private array $order

Methods

available

Indicates that the chain backend is always available.

public available(): bool

init

Initializes and orders configured backend chain members.

public init(string $namespace): 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

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

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

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

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

Parameters

Parameter	Type	Description
$key	string	cache key

clear

Clears all configured backends.

public clear(): bool

setExpireTimeout

Updates expire timeout option across all configured backends.

public setExpireTimeout(int $timeout): 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(): void

count

Returns key count from the first backend in the chain.

public count(): int

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Generated by Hazaar API Doc Generator on Tue, 21 Apr 2026 04:00:25 +0000