Cassette is a collection of queue-related classes for iOS and macOS. It is maintained by LinkedIn. Cassette was originally implemented by Segment. Cassette was inspired by Tape.
QueueFile is an efficient, file-based FIFO queue. Addition and removal from an instance is an O(1) operation. Writes are synchronous; data will be written to disk before an operation returns. The queue is intended to be reliable and survive system or process crashes.
target 'MyApp' do
pod 'Cassette', '1.0.0-beta3'
end
Download the latest binary of the library.
CASObjectQueue works with arbitrary objects that abide by the NSCoding protocol. An CASObjectQueue may be backed by a persistent CASQueueFile, or in memory.
CASObjectQueue<NSNumber *> *queue;
// Persistent ObjectQueue
NSError *error;
queue = [[CASFileObjectQueue alloc] initWithRelativePath:@"Test-File" error:&error];
// In-Memory ObjectQueue
queue = [[CASInMemoryObjectQueue alloc] init];
Add some data to the end of the queue.
NSError *error;
if ([queue add:@1 error:&error]) {
// Success
} else {
NSLog(@"Error: %@", error);
}
Read data at the head of the queue.
// Peek the eldest element. Note that -peek:error: on an empty queue
// returns @[], but on error (e.g., I/O error) it returns nil.
NSNumber *data = [queue peek:1 error:&error].firstObject;
// Peek the eldest `n` elements.
NSArray<NSNumber *> *data = [queue peek:n error:&error];
Remove processed elements.
// Remove the eldest element.
if ([queue pop:1 error:&error]) { ... }
// Remove 'n' elements.
if ([queue pop:n error:&error]) { ... }
// Remove all elements.
if ([queue clearAndReturnError:&error]) { ... }