* MBeanServerConnnection rootConnection = ...;
*
* // create a view at the local root of the namespace hierarchy.
* //
* JMXNamespaceView view = new JMXNamespaceView(rootConnection);
*
* // list all top level namespaces
* String[] list = view.list();
*
* // select one namespace from the list
* String whereToGo = ... ;
*
* // go down to the selected namespace:
* view = view.down(whereToGo);
* System.out.println("I am now in: " + view.where());
* System.out.println("I can see these MBeans:" +
* view.getMBeanServerConnection().queryNames(null,null));
*
* // list sub namespaces in current view ('whereToGo')
* list = view.list();
* System.out.println("Here are the sub namespaces of "+view.where()+": "+
* Arrays.toString(list));
*
* // go up one level
* view = view.up();
* System.out.println("I am now back to: " +
* (view.isRoot() ? "root namespace" : view.where()));
*
* @since 1.7
*/
public class JMXNamespaceView {
private static final ObjectName ALL_NAMESPACES;
static {
try {
ALL_NAMESPACES = ObjectName.getInstance("*" +
JMXNamespaces.NAMESPACE_SEPARATOR + ":"+
JMXNamespace.TYPE_ASSIGNMENT);
} catch (MalformedObjectNameException x) {
throw new ExceptionInInitializerError(x);
}
}
private static final int NAMESPACE_SEPARATOR_LENGTH =
JMXNamespaces.NAMESPACE_SEPARATOR.length();
private final JMXNamespaceView parent;
private final MBeanServerConnection here;
private final String where;
private static MBeanServerConnection checkRoot(MBeanServerConnection root) {
if (root == null)
throw new IllegalArgumentException(
"namespaceRoot: null is not a valid value");
return root;
}
/**
* Creates a view at the top of a JMX namespace hierarchy.
* @param namespaceRoot The {@code MBeanServerConnection} at the
* top of the hierarchy.
*/
public JMXNamespaceView(MBeanServerConnection namespaceRoot) {
this(null,checkRoot(namespaceRoot),"");
}
// This constructor should remain private. A user can only create
// JMXNamespaceView at the top of the hierarchy.
// JMXNamespaceView sub nodes are created by their parent nodes.
private JMXNamespaceView(JMXNamespaceView parent,
MBeanServerConnection here, String where) {
this.parent = parent;
this.here = here;
this.where = where;
}
/**
* Returns the path leading to the namespace in this view, from
* the top of the hierarchy.
* @return The path to the namespace in this view.
*/
public String where() {
return where;
}
/**
* Lists all direct sub namespaces in this view. The returned strings
* do not contain the {@code //} separator.
*
* @return A list of direct sub name spaces accessible from this
* namespace.
* @throws IOException if the attempt to list the namespaces fails because
* of a communication problem.
*/
public String[] list() throws IOException {
final Set
* JMX.narrowToNamespace(this.root().getMBeanServerConnection(),
* this.where());
*
* @return A MBeanServerConnection to the namespace shown by this view.
*/
public MBeanServerConnection getMBeanServerConnection() {
return here;
}
/**
* Get the name of the JMXNamespaceMBean handling the namespace shown by * this view, relative to the root of the hierarchy. If we are at the root * of the hierarchy, this method returns {@code null}.
* *You can use this method to make a proxy for the JMXNamespaceMBean * as follows:
* *
* JMXNamespaceView view = ...;
* ObjectName namespaceMBeanName = view.getJMXNamespaceMBeanName();
* JMXNamespaceMBean namespaceMBean = JMX.newMBeanProxy(
* view.root().getMBeanServerConnection(), namespaceMBeanName,
* JMXNamespaceMBean.class);
*
*
* @return The name of the {@code JMXNamespaceMBean} handling the namespace
* shown by this view, or {@code null}.
*/
public ObjectName getJMXNamespaceMBeanName() {
if (parent == null)
return null;
else
return JMXNamespaces.getNamespaceObjectName(where);
}
@Override
public int hashCode() {
return where.hashCode();
}
/**
* Returns true if this object is equal to the given object. The
* two objects are equal if the other object is also a {@code
* JMXNamespaceView} and both objects have the same {@linkplain #root root}
* MBeanServerConnection and the same {@linkplain #where path}.
* @param o the other object to compare to.
* @return true if both objects are equal.
*/
@Override
public boolean equals(Object o) {
if (o==this) return true;
if (! (o instanceof JMXNamespaceView)) return false;
if (!where.equals(((JMXNamespaceView)o).where)) return false;
return root().getMBeanServerConnection().equals(
((JMXNamespaceView)o).root().getMBeanServerConnection());
}
private JMXNamespaceView makeJMXNamespaceView(final JMXNamespaceView root,
final JMXNamespaceView directParent, final String pathFromRoot) {
if (pathFromRoot.equals("")) return root;
return new JMXNamespaceView(directParent,
narrowToNamespace(root.getMBeanServerConnection(),
pathFromRoot),pathFromRoot);
}
private MBeanServerConnection narrowToNamespace(MBeanServerConnection root,
String path) {
if (root instanceof MBeanServer)
return JMXNamespaces.narrowToNamespace((MBeanServer)root, path);
return JMXNamespaces.narrowToNamespace(root, path);
}
}