+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- * Copyright (C) 2015 EfficiOS Inc.
- * Copyright (C) 2015 Alexandre Montplaisir <alexmonthy@efficios.com>
- */
-
-package org.lttng.ust.agent.filter;
-
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-
-import org.lttng.ust.agent.session.EventRule;
-
-/**
- * Singleton class managing the filter notifications.
- *
- * Applications can register a {@link IFilterChangeListener} to be notified when
- * event filtering rules change in the tracing sessions.
- *
- * @author Alexandre Montplaisir
- */
-public final class FilterChangeNotifier {
-
- /** Lazy-loaded singleton instance object */
- private static FilterChangeNotifier instance = null;
-
- private final Map<EventRule, Integer> enabledEventRules = new HashMap<EventRule, Integer>();
- private final Collection<IFilterChangeListener> registeredListeners = new LinkedList<IFilterChangeListener>();
-
-
- /**
- * Private constructor, singleton class should not be instantiated directly.
- */
- private FilterChangeNotifier() {
- }
-
- /**
- * Get the singleton instance, initializing it if needed.
- *
- * @return The singleton instance
- */
- public static synchronized FilterChangeNotifier getInstance() {
- if (instance == null) {
- instance = new FilterChangeNotifier();
- }
- return instance;
- }
-
- /**
- * Notify the filter manager that a new rule was enabled in a tracing
- * session ("lttng enable-event ...")
- *
- * This is meant to be called by the LTTng Agent only. External Java
- * applications should not call this.
- *
- * @param rule
- * The rule that was added
- */
- public synchronized void addEventRule(EventRule rule) {
- Integer count = enabledEventRules.get(rule);
- if (count == null) {
- /*
- * This is the first instance of this rule being enabled. Add it to
- * the map and send notifications to the registered notifiers.
- */
- enabledEventRules.put(rule, Integer.valueOf(1));
- notifyForAddedRule(rule);
- return;
- }
- if (count.intValue() <= 0) {
- /* It should not have been in the map! */
- throw new IllegalStateException();
- }
- /*
- * This exact event rule was already enabled, just increment its
- * refcount without sending notifications
- */
- enabledEventRules.put(rule, Integer.valueOf(count.intValue() + 1));
- }
-
- /**
- * Notify the filter manager that an event name was disabled in the tracing
- * sessions ("lttng disable-event ...").
- *
- * The "disable-event" only specifies an event name. This means all the
- * rules containing this event name are to be disabled.
- *
- * This is meant to be called by the LTTng Agent only. External Java
- * applications should not call this.
- *
- * @param eventName
- * The event name to disable
- */
- public synchronized void removeEventRules(String eventName) {
- List<EventRule> rulesToRemove = new LinkedList<EventRule>();
-
- for (EventRule eventRule : enabledEventRules.keySet()) {
- if (eventRule.getEventName().equals(eventName)) {
- rulesToRemove.add(eventRule);
- }
- }
- /*
- * We cannot modify the map while iterating on it. We have to do the
- * removal separately from the iteration above.
- */
- for (EventRule rule : rulesToRemove) {
- removeEventRule(rule);
- }
- }
-
- private synchronized void removeEventRule(EventRule eventRule) {
- Integer count = enabledEventRules.get(eventRule);
- if (count == null || count.intValue() <= 0) {
- /*
- * We were asked us to disable an event rule that was not enabled
- * previously. Command error?
- */
- throw new IllegalStateException();
- }
- if (count.intValue() == 1) {
- /*
- * This is the last instance of this event rule being disabled,
- * remove it from the map and send notifications of this rule being
- * gone.
- */
- enabledEventRules.remove(eventRule);
- notifyForRemovedRule(eventRule);
- return;
- }
- /*
- * Other sessions/daemons are still looking for this event rule, simply
- * decrement its refcount, and do not send notifications.
- */
- enabledEventRules.put(eventRule, Integer.valueOf(count.intValue() - 1));
-
- }
-
- /**
- * Register a new listener to the manager.
- *
- * @param listener
- * The listener to add
- */
- public synchronized void registerListener(IFilterChangeListener listener) {
- registeredListeners.add(listener);
-
- /* Send the current rules to the new listener ("statedump") */
- for (EventRule rule : enabledEventRules.keySet()) {
- listener.eventRuleAdded(rule);
- }
- }
-
- /**
- * Unregister a listener from the manager.
- *
- * @param listener
- * The listener to remove
- */
- public synchronized void unregisterListener(IFilterChangeListener listener) {
- registeredListeners.remove(listener);
- }
-
- private void notifyForAddedRule(final EventRule rule) {
- for (IFilterChangeListener notifier : registeredListeners) {
- notifier.eventRuleAdded(rule);
- }
- }
-
- private void notifyForRemovedRule(final EventRule rule) {
- for (IFilterChangeListener notifier : registeredListeners) {
- notifier.eventRuleRemoved(rule);
- }
- }
-}
projects / lttng-ust.git / blobdiff