Interface EventRequest

All Superinterfaces:: Mirror

All Known Subinterfaces:: AccessWatchpointRequest, BreakpointRequest, ClassPrepareRequest, ClassUnloadRequest, ExceptionRequest, MethodEntryRequest, MethodExitRequest, ModificationWatchpointRequest, MonitorContendedEnteredRequest, MonitorContendedEnterRequest, MonitorWaitedRequest, MonitorWaitRequest, StepRequest, ThreadDeathRequest, ThreadStartRequest, VMDeathRequest, WatchpointRequest

public interface EventRequest
extends Mirror

Represents a request for notification of an event. Examples include BreakpointRequest and ExceptionRequest. When an event occurs for which an enabled request is present, an EventSet will be placed on the EventQueue. The collection of existing event requests is managed by the EventRequestManager.

The number of events generated for an event request can be controlled through filters. Filters provide additional constraints that an event must satisfy before it is placed on the event queue. Multiple filters can be used by making multiple calls to filter addition methods such as ExceptionRequest.addClassFilter(java.lang.String classPattern). Filters are added to an event one at a time only while the event is disabled. Multiple filters are applied with CUT-OFF AND, in the order it was added to the request. Only events that satisfy all filters are placed in the event queue.

The set of available filters is dependent on the event request, some examples of filters are:

Thread filters allow control over the thread for which events are generated.
Class filters allow control over the class in which the event occurs.
Instance filters allow control over the instance in which the event occurs.
Count filters allow control over the number of times an event is reported.

Filters can dramatically improve debugger performance by reducing the amount of event traffic sent from the target VM to the debugger VM.

Any method on EventRequest which takes EventRequest as an parameter may throw VMDisconnectedException if the target VM is disconnected and the VMDisconnectEvent has been or is available to be read from the EventQueue.

Any method on EventRequest which takes EventRequest as an parameter may throw VMOutOfMemoryException if the target VM has run out of memory.

Since:: 1.3
See Also:: BreakpointEvent, EventQueue, EventRequestManager

Fields

Modifier and Type	Field	Description
`static int`	`SUSPEND_ALL`	Suspend all threads when the event occurs
`static int`	`SUSPEND_EVENT_THREAD`	Suspend only the thread which generated the event when the event occurs
`static int`	`SUSPEND_NONE`	Suspend no threads when the event occurs

Methods

Modifier and Type	Method	Description
`void`	`addCountFilter(int count)`	Limit the requested event to be reported at most once after a given number of occurrences.
`void`	`disable()`	Same as `setEnabled(false)`.
`void`	`enable()`	Same as `setEnabled(true)`.
`Object`	`getProperty(Object key)`	Returns the value of the property with the specified key.
`boolean`	`isEnabled()`	Determines if this event request is currently enabled.
`void`	`putProperty(Object key, Object value)`	Add an arbitrary key/value "property" to this request.
`void`	`setEnabled(boolean val)`	Enables or disables this event request.
`void`	`setSuspendPolicy(int policy)`	Determines the threads to suspend when the requested event occurs in the target VM.
`int`	`suspendPolicy()`	Returns a value which describes the threads to suspend when the requested event occurs in the target VM.

Methods declared in interface com.sun.jdi.Mirror

toString, virtualMachine

Fields

SUSPEND_NONE

static final int SUSPEND_NONE

Suspend no threads when the event occurs

See Also:: Constant Field Values

SUSPEND_EVENT_THREAD

static final int SUSPEND_EVENT_THREAD

Suspend only the thread which generated the event when the event occurs

See Also:: Constant Field Values

SUSPEND_ALL

static final int SUSPEND_ALL

Suspend all threads when the event occurs

See Also:: Constant Field Values

Methods

isEnabled

boolean isEnabled()

Determines if this event request is currently enabled.

Returns:: true if enabled; false otherwise.

setEnabled

void setEnabled(boolean val)

Enables or disables this event request. While this event request is disabled, the event request will be ignored and the target VM will not be stopped if any of its threads reaches the event request. Disabled event requests still exist, and are included in event request lists such as EventRequestManager.breakpointRequests().

Parameters:: val - true if the event request is to be enabled; false otherwise.
Throws:: InvalidRequestStateException - if this request has been deleted.; IllegalThreadStateException - if this is a StepRequest, val is true, and the thread named in the request has died or is not yet started.

enable

void enable()

Same as setEnabled(true).

Throws:: InvalidRequestStateException - if this request has been deleted.; IllegalThreadStateException - if this is a StepRequest and the thread named in the request has died or is not yet started.

disable

void disable()

Same as setEnabled(false).

Throws:: InvalidRequestStateException - if this request has been deleted.

addCountFilter

void addCountFilter(int count)

Limit the requested event to be reported at most once after a given number of occurrences. The event is not reported the first count - 1 times this filter is reached. To request a one-off event, call this method with a count of 1.

Once the count reaches 0, any subsequent filters in this request are applied. If none of those filters cause the event to be suppressed, the event is reported. Otherwise, the event is not reported. In either case subsequent events are never reported for this request.

Parameters:: count - the number of ocurrences before generating an event.
Throws:: InvalidRequestStateException - if this request is currently enabled or has been deleted. Filters may be added only to disabled requests.; IllegalArgumentException - if count is less than one.

setSuspendPolicy

void setSuspendPolicy(int policy)

Determines the threads to suspend when the requested event occurs in the target VM. Use SUSPEND_ALL to suspend all threads in the target VM (the default). Use SUSPEND_EVENT_THREAD to suspend only the thread which generated the event. Use SUSPEND_NONE to suspend no threads.

Thread suspensions through events have the same functionality as explicitly requested suspensions. See ThreadReference.suspend() and VirtualMachine.suspend() for details.

Parameters:: policy - the selected suspend policy.
Throws:: InvalidRequestStateException - if this request is currently enabled or has been deleted. Suspend policy may only be set in disabled requests.; IllegalArgumentException - if the policy argument contains an illegal value.

suspendPolicy

int suspendPolicy()

Returns a value which describes the threads to suspend when the requested event occurs in the target VM. The returned value is SUSPEND_ALL, SUSPEND_EVENT_THREAD, or SUSPEND_NONE.

Returns:: the current suspend mode for this request

putProperty

void putProperty(Object key,
                 Object value)

Add an arbitrary key/value "property" to this request. The property can be used by a client of the JDI to associate application information with the request; These client-set properties are not used internally by the JDI.

The get/putProperty methods provide access to a small per-instance map. This is not to be confused with Properties.

If value is null this method will remove the property.

See Also:: getProperty(java.lang.Object)

getProperty

Object getProperty(Object key)

Returns the value of the property with the specified key. Only properties added with putProperty(java.lang.Object, java.lang.Object) will return a non-null value.

Returns:: the value of this property or null
See Also:: putProperty(java.lang.Object, java.lang.Object)

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https://docs.oracle.com/en/java/javase/11/docs/api/jdk.jdi/com/sun/jdi/request/EventRequest.html