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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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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);

}