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package com.sun.jdi.request;
import com.sun.jdi.*;
/**
* Represents a request for notification of an event. Examples include
* {@link BreakpointRequest} and {@link ExceptionRequest}.
* When an event occurs for which an enabled request is present,
* an {@link com.sun.jdi.event.EventSet EventSet} will
* be placed on the {@link com.sun.jdi.event.EventQueue EventQueue}.
* The collection of existing event requests is
* managed by the {@link EventRequestManager}.
* <p>
* 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
* {@link 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.
* <p>
* The set of available filters is dependent on the event request,
* some examples of filters are:
* <ul>
* <li>Thread filters allow control over the thread for which events are
* generated.
* <li>Class filters allow control over the class in which the event
* occurs.
* <li>Instance filters allow control over the instance in which
* the event occurs.
* <li>Count filters allow control over the number of times an event
* is reported.
* </ul>
* Filters can dramatically improve debugger performance by reducing the
* amount of event traffic sent from the target VM to the debugger VM.
* <p>
* Any method on {@code EventRequest} which
* takes {@code EventRequest} as an parameter may throw
* {@link com.sun.jdi.VMDisconnectedException} if the target VM is
* disconnected and the {@link com.sun.jdi.event.VMDisconnectEvent} has been or is
* available to be read from the {@link com.sun.jdi.event.EventQueue}.
* <p>
* Any method on {@code EventRequest} which
* takes {@code EventRequest} as an parameter may throw
* {@link com.sun.jdi.VMOutOfMemoryException} if the target VM has run out of memory.
*
* @see com.sun.jdi.event.BreakpointEvent
* @see com.sun.jdi.event.EventQueue
* @see EventRequestManager
*
* @author Robert Field
* @since 1.3
*/
public interface EventRequest extends Mirror {
/**
* Determines if this event request is currently enabled.
*
* @return {@code true} if enabled;
* {@code false} otherwise.
*/
boolean isEnabled();
/**
* 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
* {@link EventRequestManager#breakpointRequests()}.
*
* @param val {@code true} if the event request is to be enabled;
* {@code false} otherwise.
* @throws InvalidRequestStateException if this request
* has been deleted.
* @throws IllegalThreadStateException if this is a StepRequest,
* {@code val} is {@code true}, and the
* thread named in the request has died or is not yet started.
*/
void setEnabled(boolean val);
/**
* Same as {@link #setEnabled setEnabled(true)}.
* @throws InvalidRequestStateException if this request
* has been deleted.
* @throws IllegalThreadStateException if this is a StepRequest
* and the thread named in the request has died or is not yet started.
*/
void enable();
/**
* Same as {@link #setEnabled setEnabled(false)}.
* @throws InvalidRequestStateException if this request
* has been deleted.
*/
void disable();
/**
* Limit the requested event to be reported at most once after a
* given number of occurrences. The event is not reported
* the first {@code count - 1} times this filter is reached.
* To request a one-off event, call this method with a count of 1.
* <p>
* 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.
*
* @param 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.
* @throws IllegalArgumentException if {@code count}
* is less than one.
*/
void addCountFilter(int count);
/** Suspend no threads when the event occurs */
int SUSPEND_NONE = 0;
/** Suspend only the thread which generated the event when the event occurs */
int SUSPEND_EVENT_THREAD = 1;
/** Suspend all threads when the event occurs */
int SUSPEND_ALL = 2;
/**
* Determines the threads to suspend when the requested event occurs
* in the target VM. Use {@link #SUSPEND_ALL} to suspend all
* threads in the target VM (the default). Use {@link #SUSPEND_EVENT_THREAD}
* to suspend only the thread which generated the event. Use
* {@link #SUSPEND_NONE} to suspend no threads.
* <p>
* Thread suspensions through events have the same functionality
* as explicitly requested suspensions. See
* {@link com.sun.jdi.ThreadReference#suspend} and
* {@link com.sun.jdi.VirtualMachine#suspend} for details.
*
* @param 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.
* @throws IllegalArgumentException if the policy argument
* contains an illegal value.
*/
void setSuspendPolicy(int policy);
/**
* Returns a value which describes the threads to suspend when the
* requested event occurs in the target VM.
* The returned value is {@link #SUSPEND_ALL},
* {@link #SUSPEND_EVENT_THREAD}, or {@link #SUSPEND_NONE}.
*
* @return the current suspend mode for this request
*/
int suspendPolicy();
/**
* 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.
* <p>
* The {@code get/putProperty} methods provide access to
* a small per-instance map. This is <b>not</b> to be confused
* with {@link java.util.Properties}.
* <p>
* If value is null this method will remove the property.
*
* @see #getProperty
*/
void putProperty(Object key, Object value);
/**
* Returns the value of the property with the specified key. Only
* properties added with {@link #putProperty} will return
* a non-null value.
*
* @return the value of this property or null
* @see #putProperty
*/
Object getProperty(Object key);
}