/*
* Copyright (c) 2008, 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 com.sun.tracing;
/**
* The {@code Probe} interface represents a tracepoint.
*
* A {@code Probe} instance is obtained by calling the
* {@code Provider.getProbe()} method of a provider instance created by
* {@code ProviderFactory.createProvider()}. A {@code Probe} can be used to
* trigger a probe manually (provided the correct arguments are passed to
* it), or to check a probe to see if anything is currently tracing it.
* <p>
* A tracing check can be used to avoid lengthy work that might be
* needed to set up the probe's arguments. However, checking
* whether the probe is enabled generally takes the same amount of time
* as actually triggering the probe. So, you should only check a probe's status
* without triggering it if setting up the arguments is very expensive.
* <p>
* Users do not need to implement this interface: instances are
* created automatically by the system when a {@code Provider)} instance is
* created.
* <p>
* @since 1.7
*/
public interface Probe {
/**
* Checks whether there is an active trace of this probe.
*
* @return true if an active trace is detected.
*/
boolean isEnabled();
/**
* Determines whether a tracepoint is enabled.
*
* Typically, users do not need to use this method. It is called
* automatically when a Provider's instance method is called. Calls to
* this method expect the arguments to match the declared parameters for
* the method associated with the probe.
*
* @param args the parameters to pass to the method.
* @throws IllegalArgumentException if the provided parameters do not
* match the method declaration for this probe.
*/
void trigger(Object ... args);
}