/*

 * Copyright (c) 2016, 2018, 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 jdk.jfr.internal.handlers;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import jdk.jfr.EventType;

import jdk.jfr.internal.EventControl;

import jdk.jfr.internal.JVM;

import jdk.jfr.internal.PlatformEventType;

import jdk.jfr.internal.PrivateAccess;

import jdk.jfr.internal.StringPool;

// Users should not be subclass for security reasons.

public abstract class EventHandler {

    // Accessed by generated sub class

    protected final PlatformEventType platformEventType;

    private final EventType eventType;

    private final EventControl eventControl;

    // Accessed by generated sub class

    protected EventHandler(boolean registered, EventType eventType, EventControl eventControl) {

        if (System.getSecurityManager() != null) {

            // Do not allow user subclasses when security is enforced.

            if (EventHandler.class.getClassLoader() != this.getClass().getClassLoader()) {

                throw new SecurityException("Illegal subclass");

            }

        }

        this.eventType = eventType;

        this.platformEventType = PrivateAccess.getInstance().getPlatformEventType(eventType);

        this.eventControl = eventControl;

        platformEventType.setRegistered(registered);

    }

    final protected StringPool createStringFieldWriter() {

        return new StringPool();

    }

    // Accessed by generated code in event class

    public final boolean shouldCommit(long duration) {

        return isEnabled() && duration >= platformEventType.getThresholdTicks();

    }

    // Accessed by generated code in event class

    // Accessed by generated sub class

    public final boolean isEnabled() {

        return platformEventType.isCommitable();

    }

    public final EventType getEventType() {

        return eventType;

    }

    public final PlatformEventType getPlatformEventType() {

        return platformEventType;

    }

    public final EventControl getEventControl() {

        return eventControl;

    }

    public static long timestamp() {

        return JVM.counterTime();

    }

    public static long duration(long startTime) {

        if (startTime == 0) {

            // User forgot to invoke begin, or instrumentation was

            // added after the user invoked begin.

            // Returning 0 will make it an instant event

            return 0;

        }

        return timestamp() - startTime;

    }

    // Prevent a malicious user from instantiating a generated event handlers.

    @Override

    public final Object clone() throws java.lang.CloneNotSupportedException {

        throw new CloneNotSupportedException();

    }

    private final void writeObject(ObjectOutputStream out) throws IOException {

        throw new IOException("Object cannot be serialized");

    }

    private final void readObject(ObjectInputStream in) throws IOException {

        throw new IOException("Class cannot be deserialized");

    }

    public boolean isRegistered() {

        return platformEventType.isRegistered();

    }

    public boolean setRegistered(boolean registered) {

       return platformEventType.setRegistered(registered);

    }

}