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/*
* 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
* null.
*
* @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
* null 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 - 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 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 interval 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 errored 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 null if no such error has occurred.
*
* @return Exception - the last exception that occurred during polling
* or null if no error condition exists.
* @see #isErrored
* @see #setLastException
*/
Exception getLastException();
/**
* Clear the last exception.
*
* Calling this method will clear the errored 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;
}