Java API

import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.xpack.client.PreBuiltXPackTransportClient;
import org.elasticsearch.xpack.core.XPackClient;
import org.elasticsearch.xpack.core.XPackPlugin;
import org.elasticsearch.core.watcher.client.WatcherClient;
...

TransportClient client = new PreBuiltXPackTransportClient(Settings.builder()
    .put("cluster.name", "myClusterName")
    ...
    .build())
    .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9300));

XPackClient xpackClient = new XPackClient(client);
WatcherClient watcherClient = xpackClient.watcher();

WatchSourceBuilder watchSourceBuilder = WatchSourceBuilders.watchBuilder();

// Set the trigger
watchSourceBuilder.trigger(TriggerBuilders.schedule(Schedules.cron("0 0/1 * * * ?")));

// Create the search request to use for the input
SearchRequest request = Requests.searchRequest("idx").source(searchSource()
        .query(boolQuery()
                .must(matchQuery("response", 404))
                .filter(rangeQuery("date").gt("{{ctx.trigger.scheduled_time}}"))
                .filter(rangeQuery("date").lt("{{ctx.execution_time}}"))
        ));

// Create the search input
SearchInput input = new SearchInput(new WatcherSearchTemplateRequest(new String[]{"idx"}, null, SearchType.DEFAULT,
    WatcherSearchTemplateRequest.DEFAULT_INDICES_OPTIONS, new BytesArray(request.source().toString())), null, null, null);

// Set the input
watchSourceBuilder.input(input);

// Set the condition
watchSourceBuilder.condition(new ScriptCondition(new Script("ctx.payload.hits.total > 1")));

// Create the email template to use for the action
EmailTemplate.Builder emailBuilder = EmailTemplate.builder();
emailBuilder.to("someone@domain.host.com");
emailBuilder.subject("404 recently encountered");
EmailAction.Builder emailActionBuilder = EmailAction.builder(emailBuilder.build());

// Add the action
watchSourceBuilder.addAction("email_someone", emailActionBuilder);

PutWatchResponse putWatchResponse = watcherClient.preparePutWatch("my-watch")
    .setSource(watchSourceBuilder)
    .get();

PutWatchResponse putWatchResponse2 = watcherClient.preparePutWatch("my-watch")
        .setSource(watchBuilder()
                .trigger(schedule(cron("0 0/1 * * * ?")))
                .input(searchInput(new WatcherSearchTemplateRequest(new String[]{"idx"}, null, SearchType.DEFAULT,
                        WatcherSearchTemplateRequest.DEFAULT_INDICES_OPTIONS, searchSource()
                        .query(boolQuery()
                                .must(matchQuery("response", 404))
                                .filter(rangeQuery("date").gt("{{ctx.trigger.scheduled_time}}"))
                                .filter(rangeQuery("date").lt("{{ctx.execution_time}}"))
                        ).buildAsBytes())))
                .condition(compareCondition("ctx.payload.hits.total", CompareCondition.Op.GT, 1L))
                .addAction("email_someone", emailAction(EmailTemplate.builder()
                        .to("someone@domain.host.com")
                        .subject("404 recently encountered"))))
        .get();

GetWatchResponse getWatchResponse = watcherClient.prepareGetWatch("my-watch").get();

XContentSource source = getWatchResponse.getSource();

Map<String, Object> map = source.getAsMap();

String host = source.getValue("input.http.request.host");

DeleteWatchResponse deleteWatchResponse = watcherClient.prepareDeleteWatch("my-watch").get();

ExecuteWatchResponse executeWatchResponse = watcherClient.prepareExecuteWatch("my-watch")

    // execute the actions, ignoring the watch condition
    .setIgnoreCondition(true)

    // A map containing alternative input to use instead of the output of
    // the watch's input
    .setAlternativeInput(new HashMap<String, Object>())

    // Trigger data to use (Note that "scheduled_time" is not provided to the
    // ctx.trigger by this execution method so you may want to include it here)
    .setTriggerData(new HashMap<String, Object>())

    // Simulating the "email_admin" action while ignoring its throttle state. Use
    // "_all" to set the action execution mode to all actions
    .setActionMode("_all", ActionExecutionMode.FORCE_SIMULATE)

    // If the execution of this watch should be written to the `.watcher-history`
    // index and reflected in the persisted Watch
    .setRecordExecution(false)

    // Indicates whether the watch should execute in debug mode. In debug mode the
    // returned watch record will hold the execution vars
    .setDebug(true)

    .get();

XContentSource source = executeWatchResponse.getRecordSource();
String actionId = source.getValue("result.actions.0.id");

GetWatchResponse getWatchResponse = watcherClient.prepareGetWatch("my-watch").get();
State state = getWatchResponse.getStatus().actionStatus("my-action").ackStatus().state();

AckWatchResponse ackResponse = watcherClient.prepareAckWatch("my-watch").setActionIds("my-action").get();

WatchStatus status = ackResponse.getStatus();
ActionStatus actionStatus = status.actionStatus("my-action");
ActionStatus.AckStatus ackStatus = actionStatus.ackStatus();
ActionStatus.AckStatus.State ackState = ackStatus.state();

AckWatchResponse ackResponse = watcherClient.prepareAckWatch("my-watch")
  .setActionIds("action1", "action2")
  .get();

AckWatchResponse ackResponse = watcherClient.prepareAckWatch("my-watch").get();

GetWatchResponse getWatchResponse = watcherClient.prepareGetWatch("my-watch").get();
boolean active = getWatchResponse.getStatus().state().isActive();

ActivateWatchResponse activateResponse = watcherClient.prepareActivateWatch("my-watch", true).get();
boolean active = activateResponse.getStatus().state().isActive();

GetWatchResponse getWatchResponse = watcherClient.prepareGetWatch("my-watch").get();
boolean active = getWatchResponse.getStatus().state().isActive();

ActivateWatchResponse activateResponse = watcherClient.prepareActivateWatch("my-watch", false).get();
boolean active = activateResponse.getStatus().state().isActive();

WatcherStatsResponse watcherStatsResponse = watcherClient.prepareWatcherStats().get();

WatcherBuild build = watcherStatsResponse.getBuild();

// The current size of the watcher execution queue
long executionQueueSize = watcherStatsResponse.getThreadPoolQueueSize();

// The maximum size the watch execution queue has grown to
long executionQueueMaxSize = watcherStatsResponse.getThreadPoolQueueSize();

// The total number of watches registered in the system
long totalNumberOfWatches = watcherStatsResponse.getWatchesCount();

// {watcher} state (STARTING,STOPPED or STARTED)
WatcherState watcherState = watcherStatsResponse.getWatcherState();

WatcherServiceResponse watcherServiceResponse = watcherClient.prepareWatchService().start().get();

WatcherServiceResponse watcherServiceResponse = watcherClient.prepareWatchService().stop().get();

WatcherServiceResponse watcherServiceResponse = watcherClient.prepareWatchService().restart().get();