# `Pulsar.ProducerEpochStore`
[🔗](https://github.com/efcasado/pulsar-elixir/blob/main/lib/pulsar/producer_epoch_store.ex#L1)

Manages persistent storage of producer topic epochs across restarts.

This module provides an abstraction layer over ETS for storing and retrieving
topic epochs for producers. The epochs are used to detect when a producer has
been fenced by a newer producer with ExclusiveWithFencing access mode.

Each client maintains its own isolated epoch store, created when the client
starts and cleaned up when the client stops.

# `delete`

```elixir
@spec delete(atom(), String.t(), String.t(), atom()) :: :ok | :error
```

Deletes the stored epoch for a producer.

## Parameters

- `client_name` - The name of the client
- `topic` - The topic name
- `producer_name` - The producer name
- `access_mode` - The producer access mode

## Returns

`:ok` if successful, `:error` if the table doesn't exist

## Examples

    iex> ProducerEpochStore.delete(:default, "my-topic", "my-producer", :Exclusive)
    :ok

# `get`

```elixir
@spec get(atom(), String.t(), String.t(), atom()) :: {:ok, integer()} | :error
```

Retrieves the stored epoch for a producer.

## Parameters

- `client_name` - The name of the client
- `topic` - The topic name
- `producer_name` - The producer name
- `access_mode` - The producer access mode

## Returns

- `{:ok, epoch}` if an epoch is found
- `:error` if no epoch is stored

## Examples

    iex> ProducerEpochStore.get(:default, "my-topic", "my-producer", :Exclusive)
    {:ok, 5}

    iex> ProducerEpochStore.get(:default, "new-topic", "new-producer", :Shared)
    :error

# `init`

```elixir
@spec init(atom()) :: :ok
```

Initializes the epoch store for a client.

Creates the ETS table if it doesn't already exist. This is called
when a Pulsar client starts.

## Parameters

- `client_name` - The name of the client

## Returns

`:ok`

# `put`

```elixir
@spec put(atom(), String.t(), String.t(), atom(), integer()) :: :ok | :error
```

Stores the epoch for a producer.

## Parameters

- `client_name` - The name of the client
- `topic` - The topic name
- `producer_name` - The producer name
- `access_mode` - The producer access mode
- `epoch` - The topic epoch to store

## Returns

`:ok` if successful, `:error` if the table doesn't exist

## Examples

    iex> ProducerEpochStore.put(:default, "my-topic", "my-producer", :Exclusive, 5)
    :ok

# `table_name`

```elixir
@spec table_name(atom()) :: atom()
```

Returns the ETS table name for a given client.

---

*Consult [api-reference.md](api-reference.md) for complete listing*