Package com.google.cloud.spanner.watcher

Interface SpannerTableChangeWatcher

All Superinterfaces:

com.google.api.core.ApiService

All Known Implementing Classes:

SpannerTableTailer

public interface SpannerTableChangeWatcher
extends com.google.api.core.ApiService

Interface for capturing changes to a single Spanner table.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	SpannerTableChangeWatcher.Row	Row is passed in to the change callback and allows access to the most recent data.
static interface	SpannerTableChangeWatcher.RowChangeCallback	Interface for receiving asynchronous callbacks when a row has been inserted or updated.

Nested classes/interfaces inherited from interface com.google.api.core.ApiService

com.google.api.core.ApiService.Listener, com.google.api.core.ApiService.State

Method Summary

Modifier and Type	Method	Description
void	addCallback(SpannerTableChangeWatcher.RowChangeCallback callback)	Adds a SpannerTableChangeWatcher.RowChangeCallback for this SpannerTableChangeWatcher.
TableId	getTable()	Returns the id of the table that is monitored by this watcher.

Methods inherited from interface com.google.api.core.ApiService

addListener, awaitRunning, awaitRunning, awaitTerminated, awaitTerminated, failureCause, isRunning, startAsync, state, stopAsync

Method Detail

getTable

TableId getTable()

Returns the id of the table that is monitored by this watcher.

addCallback

void addCallback(SpannerTableChangeWatcher.RowChangeCallback callback)

Adds a SpannerTableChangeWatcher.RowChangeCallback for this SpannerTableChangeWatcher. Callbacks may only be added when the ApiService.state() of this SpannerTableChangeWatcher is ApiService.State.NEW. Callbacks should be lightweight and non-blocking. The callback should hand off any heavy computations or blocking operations to a non-blocking executor or buffer.

The SpannerTableChangeWatcher guarantees that at most one SpannerTableChangeWatcher.RowChangeCallback will be active at any given time, and all callbacks will receive all changes in order of commit timestamp. There is no guarantee as to the order of which callback is called first if a SpannerTableChangeWatcher has registered multiple callbacks.