org.apache.tomcat.util.modeler.BaseAttributeFilter Maven / Gradle / Ivy
/*
* 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.HashSet;
import java.util.Set;
import javax.management.AttributeChangeNotification;
import javax.management.Notification;
import javax.management.NotificationFilter;
/**
* Implementation of NotificationFilter for attribute change
* notifications. This class is used by BaseModelMBean to
* construct attribute change notification event filters when a filter is not
* supplied by the application.
*
* @author Craig R. McClanahan
*/
public class BaseAttributeFilter implements NotificationFilter {
private static final long serialVersionUID = 1L;
// ----------------------------------------------------------- Constructors
/**
* Construct a new filter that accepts only the specified attribute
* name.
*
* @param name Name of the attribute to be accepted by this filter, or
* null to accept all attribute names
*/
public BaseAttributeFilter(String name) {
super();
if (name != null) {
addAttribute(name);
}
}
// ----------------------------------------------------- Instance Variables
/**
* The set of attribute names that are accepted by this filter. If this
* list is empty, all attribute names are accepted.
*/
private Set names = new HashSet<>();
// --------------------------------------------------------- Public Methods
/**
* Add a new attribute name to the set of names accepted by this filter.
*
* @param name Name of the attribute to be accepted
*/
public void addAttribute(String name) {
synchronized (names) {
names.add(name);
}
}
/**
* Clear all accepted names from this filter, so that it will accept
* all attribute names.
*/
public void clear() {
synchronized (names) {
names.clear();
}
}
/**
* Return the set of names that are accepted by this filter. If this
* filter accepts all attribute names, a zero length array will be
* returned.
* @return the array of names
*/
public String[] getNames() {
synchronized (names) {
return names.toArray(new String[0]);
}
}
/**
* Test whether notification enabled for this event.
* Return true if:
*
* - This is an attribute change notification
* - Either the set of accepted names is empty (implying that all
* attribute names are of interest) or the set of accepted names
* includes the name of the attribute in this notification
*
*/
@Override
public boolean isNotificationEnabled(Notification notification) {
if (notification == null) {
return false;
}
if (!(notification instanceof AttributeChangeNotification)) {
return false;
}
AttributeChangeNotification acn =
(AttributeChangeNotification) notification;
if (!AttributeChangeNotification.ATTRIBUTE_CHANGE.equals(acn.getType())) {
return false;
}
synchronized (names) {
if (names.size() < 1) {
return true;
} else {
return names.contains(acn.getAttributeName());
}
}
}
/**
* Remove an attribute name from the set of names accepted by this
* filter.
*
* @param name Name of the attribute to be removed
*/
public void removeAttribute(String name) {
synchronized (names) {
names.remove(name);
}
}
}