/* * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.jvmstat.monitor; import java.util.List; import sun.jvmstat.monitor.event.VmListener; /** * Interface for interacting with a monitorable Java Virtual Machine. * The MonitoredVm interface provides methods for discovery of exported * instrumentation, for attaching event listeners, and for overall * maintenance of the connection to the target. * * @author Brian Doherty * @since 1.5 */public interface MonitoredVm {     /**     * Get the VmIdentifier associated with this MonitoredVm     *     * @return VmIdentifier - the fully resolved Vm identifier associated     *                        with this MonitoredVm.     */    VmIdentifier getVmIdentifier();     /**     * Find a named Instrumentation object.     *     * This method will look for the named instrumentation object in the     * instrumentation exported by this Java Virtual Machine. If an     * instrumentation object with the given name exists, a Monitor interface     * to that object will be return. Otherwise, the method returns     * <tt>null</tt>.     *     * @param name the name of the Instrumentation object to find.     * @return Monitor - the {@link Monitor} object that can be used to     *                   monitor the the named instrumentation object, or     *                   <tt>null</tt> if the named object doesn't exist.     * @throws MonitorException Thrown if an error occurs while communicating     *                          with the target Java Virtual Machine.     */    Monitor findByName(String name) throws MonitorException;     /**     * Find all Instrumentation objects with names matching the given pattern.     *     * This method returns a {@link List} of Monitor objects such that     * the name of each object matches the given pattern.     *     * @param patternString a string containing a pattern as described in     *                      {@link java.util.regex.Pattern}.     * @return List<Monitor> - a List of {@link Monitor} objects that can be used to     *                monitor the instrumentation objects whose names match     *                the given pattern. If no instrumentation objects have`     *                names matching the given pattern, then an empty List     *                is returned.     * @throws MonitorException Thrown if an error occurs while communicating     *                          with the target Java Virtual Machine.     * @see java.util.regex.Pattern     */    List<Monitor> findByPattern(String patternString) throws MonitorException;     /**     * Detach from target Java Virtual Machine.     *     * After calling this method, updates of the instrumentation data values     * may be halted. All event notifications are halted. Further interactions     * with this object should be avoided.     */    void detach();      /* ---- Methods to support polled MonitoredVm Implementations ---- */     /**     * Set the polling interval to <code>interval</code> milliseconds.     *     * Polling based monitoring implementations need to refresh the     * instrumentation data on a periodic basis. This interface allows     * the interval to override the implementation specific default     * interval.     *     * @param interval the polling interval in milliseconds     */    void setInterval(int interval);     /**     * Get the polling interval.     *     * @return int - the current polling interval in milliseconds.     * @see #setInterval     */    int getInterval();     /**     * Set the last exception encountered while polling this MonitoredVm.     *     * Polling implementations may choose to poll asynchronously. This     * method allows an asynchronous task to communicate any polling related     * exceptions with the application. When an a non-null exception is reported     * through this interface, the MonitoredVm instance is considered to     * be in the <em>errored</em> state.     *     * @param cause the exception to record.     * @see #isErrored     */    void setLastException(Exception cause);     /**     * Get the last exception encountered while polling this MonitoredVm.     *     * Returns the last exception observed by the implementation dependent     * polling task or <tt>null</tt> if no such error has occurred.     *     * @return Exception - the last exception that occurred during polling     *                     or <tt>null</tt> if no error condition exists.     * @see #isErrored     * @see #setLastException     */    Exception getLastException();     /**     * Clear the last exception.     *     * Calling this method will clear the <em>errored</em> state of this     * MonitoredVm. However, there is no guarantee that clearing the     * the errored state return the asynchronous polling task to an     * operational state.     *     */    void clearLastException();     /**     * Test if this MonitoredVm is in the errored state.     * The errored state exists only if an error was reported with     * call to {@link #setLastException} and only if the parameter to     * that call was non-null and no subsequent calls are made to     * {@link #clearLastException}.     *     * @return boolean - true if the instance has a non-null error condition     *                   set, false otherwise.     *     * @see #setLastException     * @see #getLastException     */    boolean isErrored();     /**     * Add a VmListener. The given listener is added to the list of     * VmListener objects to be notified of MonitoredVm related events.     *     * @param listener the VmListener to add.     * @throws MonitorException Thrown if any problems occur while attempting     *                          to add this listener.     */    void addVmListener(VmListener listener) throws MonitorException;     /**     * Remove a VmListener. The given listener is removed from the list of     * VmListener objects to be notified of MonitoredVm related events.     *     * @param listener the VmListener to be removed.     * @throws MonitorException Thrown if any problems occur while attempting     *                            to remove this listener.     */    void removeVmListener(VmListener listener) throws MonitorException;}