com.centurylink.mdw.monitor

Interface ServiceMonitor

All Superinterfaces:

Monitor, RegisteredService

All Known Implementing Classes:

MessageMonitor, TraceServiceMonitor

public interface ServiceMonitor
extends RegisteredService, Monitor

ServiceMonitors can be registered through @Monitor annotations to intercept service calls handled by the MDW framework. Must be threadsafe. Normally all registered monitors are called in sequence. However the first monitor whose onHandle() returns non-null breaks the chain, and this non-null response is passed back to the consumer. Same instance is guaranteed for all lifecycle methods.

Method Summary

Modifier and Type	Method and Description
default java.lang.Object	onError(java.lang.Throwable t, java.util.Map<java.lang.String,java.lang.String> headers)
default java.lang.Object	onHandle(java.lang.Object request, java.util.Map<java.lang.String,java.lang.String> headers) Called after onRequest(), but before the appropriate handler is determined.
default java.lang.Object	onRequest(java.lang.Object request, java.util.Map<java.lang.String,java.lang.String> headers) Called when the request comes in.
default java.lang.Object	onResponse(java.lang.Object response, java.util.Map<java.lang.String,java.lang.String> headers) Called before the response is sent out from the MDW event handler or camel route.

Methods inherited from interface com.centurylink.mdw.monitor.Monitor

isEnabled, isOffline

Method Detail

onRequest

default java.lang.Object onRequest(java.lang.Object request,
                                   java.util.Map<java.lang.String,java.lang.String> headers)
                            throws ServiceException

Called when the request comes in. Can change the incoming request contents. Currently must return null or a String.

Parameters:

request - Incoming request message content (String, XMLBean, JAXB Element, JSONObject, etc).

headers - Incoming protocol header values. May be modified by the monitor.

Returns:

null, or an alternative request that should be passed on instead of the incoming request

Throws:

ServiceException

onHandle

default java.lang.Object onHandle(java.lang.Object request,
                                  java.util.Map<java.lang.String,java.lang.String> headers)
                           throws ServiceException

Called after onRequest(), but before the appropriate handler is determined. Can be used to short-circuit the request. Currently must return null or a String. Returning non-null from here bypasses onResponse() and other monitors' onHandle().

Parameters:

request - Incoming request message content (String, XMLBean, JAXB Element, JSONObject, etc).

headers - protocol headers

Returns:

null, or an alternative response to send back to the service consumer

Throws:

ServiceException

onResponse

default java.lang.Object onResponse(java.lang.Object response,
                                    java.util.Map<java.lang.String,java.lang.String> headers)
                             throws ServiceException

Called before the response is sent out from the MDW event handler or camel route. Currently must return null or a String.

Parameters:

response - Outgoing response message content (probably a String, XMLBean or JAXB Element)

headers - Outbound protocol header values. May be modified by the monitor.

Returns:

null, or an alternative response to send back to the service consumer.

Throws:

ServiceException

onError

default java.lang.Object onError(java.lang.Throwable t,
                                 java.util.Map<java.lang.String,java.lang.String> headers)

Parameters:

t - Throwable error that was encountered

headers - service meta information

Returns:

alternate response or null