nxt.http

Class EventWait

java.lang.Object

nxt.http.APIServlet.APIRequestHandler

nxt.http.EventWait

public class EventWait
extends APIServlet.APIRequestHandler

The EventWait API will wait for one of the server events registered by EventRegister. EventWait will return immediately if one or more events have occurred since the last time EventWait was called. All pending events will be returned in a single response. The events remain registered so successive calls to EventWait can be made without another call to EventRegister.

Only one EventWait can be outstanding for the same network address. If a second EventWait is issued, the current EventWait will be replaced by the new EventWait.

Request parameters:

• timeout - Number of seconds to wait for an event. The EventWait will complete normally if no event is received within the timeout interval. nxt.apiEventTimeout will be used if no timeout value is specified or if the requested timeout is greater than nxt.apiEventTimeout.

Response parameters:

• events - An array of event objects

Error Response parameters:

• errorCode - API error code
• errorDescription - API error description

Event object:

• name - The event name
• ids - An array of event object identifiers

Event names:

• Block.BLOCK_GENERATED
• Block.BLOCK_POPPED
• Block.BLOCK_PUSHED
• Ledger.ADD_ENTRY.account - The account suffix will be Reed-Solomon identifier of the account associated with the ledger entry.
• Peer.ADD_INBOUND
• Peer.ADDED_ACTIVE_PEER
• Peer.BLACKLIST
• Peer.CHANGED_ACTIVE_PEER
• Peer.DEACTIVATE
• Peer.NEW_PEER
• Peer.REMOVE
• Peer.REMOVE_INBOUND
• Peer.UNBLACKLIST
• Transaction.ADDED_CONFIRMED_TRANSACTIONS
• Transaction.ADDED_UNCONFIRMED_TRANSACTIONS
• Transaction.REJECT_PHASED_TRANSACTION
• Transaction.RELEASE_PHASED_TRANSACTION
• Transaction.REMOVE_UNCONFIRMED_TRANSACTIONS

Event object identifiers:

• Block string identifier for a Block event
• Peer network address for a Peer event
• Transaction string identifier for a Transaction event

Field Summary

Fields inherited from class nxt.http.APIServlet.APIRequestHandler

DESCRIPTION_FIELD, MESSAGE_FIELD, NAME_FIELD

Method Summary

Modifier and Type	Method and Description
protected boolean	allowRequiredBlockParameters() No required block parameters
protected org.json.simple.JSONStreamAware	processRequest(javax.servlet.http.HttpServletRequest req) Process the EventWait API request The response will be returned immediately if there are any pending events.
protected boolean	requirePost()

Methods inherited from class nxt.http.APIServlet.APIRequestHandler

getAPITags, getFileParameter, getParameters, processRequest, requireBlockchain, requireFullClient, requirePassword, startDbTransaction

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

processRequest

protected org.json.simple.JSONStreamAware processRequest(javax.servlet.http.HttpServletRequest req)

Process the EventWait API request The response will be returned immediately if there are any pending events. Otherwise, an asynchronous context will be created and the response will be returned after the wait has completed. By using an asynchronous context, we avoid tying up the Jetty servlet thread while waiting for an event.

Specified by:

processRequest in class APIServlet.APIRequestHandler

Parameters:

req - API request

Returns:

API response or null

requirePost

protected final boolean requirePost()

Overrides:

requirePost in class APIServlet.APIRequestHandler

allowRequiredBlockParameters

protected boolean allowRequiredBlockParameters()

No required block parameters

Overrides:

allowRequiredBlockParameters in class APIServlet.APIRequestHandler

Returns:

FALSE to disable the required block parameters