init

java/org/apache/tomcat/util/modeler/BaseNotificationBroadcaster.java

@@ -0,0 +1,192 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package org.apache.tomcat.util.modeler;
+
+
+import java.util.ArrayList;
+import java.util.Iterator;
+
+import javax.management.ListenerNotFoundException;
+import javax.management.MBeanNotificationInfo;
+import javax.management.Notification;
+import javax.management.NotificationBroadcaster;
+import javax.management.NotificationFilter;
+import javax.management.NotificationListener;
+
+
+/**
+ * <p>Implementation of <code>NotificationBroadcaster</code> for attribute
+ * change notifications.  This class is used by <code>BaseModelMBean</code> to
+ * handle notifications of attribute change events to interested listeners.
+ *</p>
+ *
+ * @author Craig R. McClanahan
+ * @author Costin Manolache
+ */
+
+public class BaseNotificationBroadcaster implements NotificationBroadcaster {
+
+
+    // ----------------------------------------------------------- Constructors
+
+
+    // ----------------------------------------------------- Instance Variables
+
+
+    /**
+     * The set of registered <code>BaseNotificationBroadcasterEntry</code>
+     * entries.
+     */
+    protected ArrayList<BaseNotificationBroadcasterEntry> entries =
+            new ArrayList<>();
+
+
+    // --------------------------------------------------------- Public Methods
+
+
+    /**
+     * Add a notification event listener to this MBean.
+     *
+     * @param listener Listener that will receive event notifications
+     * @param filter Filter object used to filter event notifications
+     *  actually delivered, or <code>null</code> for no filtering
+     * @param handback Handback object to be sent along with event
+     *  notifications
+     *
+     * @exception IllegalArgumentException if the listener parameter is null
+     */
+    @Override
+    public void addNotificationListener(NotificationListener listener,
+                                        NotificationFilter filter,
+                                        Object handback)
+        throws IllegalArgumentException {
+
+        synchronized (entries) {
+
+            // Optimization to coalesce attribute name filters
+            if (filter instanceof BaseAttributeFilter) {
+                BaseAttributeFilter newFilter = (BaseAttributeFilter) filter;
+                for (BaseNotificationBroadcasterEntry item : entries) {
+                    if ((item.listener == listener) &&
+                        (item.filter != null) &&
+                        (item.filter instanceof BaseAttributeFilter) &&
+                        (item.handback == handback)) {
+                        BaseAttributeFilter oldFilter =
+                            (BaseAttributeFilter) item.filter;
+                        String newNames[] = newFilter.getNames();
+                        String oldNames[] = oldFilter.getNames();
+                        if (newNames.length == 0) {
+                            oldFilter.clear();
+                        } else {
+                            if (oldNames.length != 0) {
+                                for (int i = 0; i < newNames.length; i++)
+                                    oldFilter.addAttribute(newNames[i]);
+                            }
+                        }
+                        return;
+                    }
+                }
+            }
+
+            // General purpose addition of a new entry
+            entries.add(new BaseNotificationBroadcasterEntry
+                        (listener, filter, handback));
+        }
+
+    }
+
+
+    /**
+     * Return an <code>MBeanNotificationInfo</code> object describing the
+     * notifications sent by this MBean.
+     */
+    @Override
+    public MBeanNotificationInfo[] getNotificationInfo() {
+        return new MBeanNotificationInfo[0];
+    }
+
+
+    /**
+     * Remove a notification event listener from this MBean.
+     *
+     * @param listener The listener to be removed (any and all registrations
+     *  for this listener will be eliminated)
+     *
+     * @exception ListenerNotFoundException if this listener is not
+     *  registered in the MBean
+     */
+    @Override
+    public void removeNotificationListener(NotificationListener listener)
+        throws ListenerNotFoundException {
+
+        synchronized (entries) {
+            Iterator<BaseNotificationBroadcasterEntry> items =
+                entries.iterator();
+            while (items.hasNext()) {
+                BaseNotificationBroadcasterEntry item = items.next();
+                if (item.listener == listener)
+                    items.remove();
+            }
+        }
+
+    }
+
+
+    /**
+     * Send the specified notification to all interested listeners.
+     *
+     * @param notification The notification to be sent
+     */
+    public void sendNotification(Notification notification) {
+
+        synchronized (entries) {
+            for (BaseNotificationBroadcasterEntry item : entries) {
+                if ((item.filter != null) &&
+                    (!item.filter.isNotificationEnabled(notification)))
+                    continue;
+                item.listener.handleNotification(notification, item.handback);
+            }
+        }
+
+    }
+
+}
+
+
+/**
+ * Utility class representing a particular registered listener entry.
+ */
+
+class BaseNotificationBroadcasterEntry {
+
+    public BaseNotificationBroadcasterEntry(NotificationListener listener,
+                                            NotificationFilter filter,
+                                            Object handback) {
+        this.listener = listener;
+        this.filter = filter;
+        this.handback = handback;
+    }
+
+    public NotificationFilter filter = null;
+
+    public Object handback = null;
+
+    public NotificationListener listener = null;
+
+}