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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * 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,
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 *
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package com.oracle.truffle.api.instrument;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.source.Source;

/**
 * Listener for receiving the result a client-provided Guest Language expression
 * {@linkplain Instrumenter#attach(Probe, Class, Source, EvalInstrumentListener, String) attached}
 * to a {@link Probe}.
 * <p>
 * Notification is fully synchronous, so method bodies have performance implications. Non-trivial
 * methods should be coded with Truffle guidelines and cautions in mind.
 *
 * @see Instrumenter
 */
public interface EvalInstrumentListener {

    /**
     * Notifies listener that a client-provided Guest Language expression
     * {@linkplain Instrumenter#attach(Probe, Class, Source, EvalInstrumentListener, String)
     * attached} to a {@link Probe} has just been executed with the specified result, possibly
     * {@code null}.
     * <p>
     * <strong>Note: </strong> Truffle will attempt to optimize implementations through partial
     * evaluation; annotate with {@link TruffleBoundary} if this should not be permitted.
     *
     * @param node the guest language AST node at which the expression was evaluated
     * @param vFrame execution frame at the guest-language AST node
     * @param result expression evaluation
     */
    void onExecution(Node node, VirtualFrame vFrame, Object result);

    /**
     * Notifies listener that a client-provided Guest Language expression
     * {@linkplain Instrumenter#attach(Probe, Class, Source, EvalInstrumentListener, String)
     * attached} to a {@link Probe} has just been executed and generated an exception. The exception
     * does not affect Guest language evaluation; the only report is to listeners implementing this
     * methods.
     * <p>
     * <strong>Note: </strong> Truffle will attempt to optimize implementations through partial
     * evaluation; annotate with {@link TruffleBoundary} if this should not be permitted.
     *
     * @param node the guest-language AST node to which the host Instrument's {@link Probe} is
     *            attached
     * @param vFrame execution frame at the guest-language AST node
     * @param ex the exception
     */
    void onFailure(Node node, VirtualFrame vFrame, Exception ex);

}