src/java.base/share/classes/jdk/internal/vm/ContinuationSupport.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package jdk.internal.vm;

/**
 * Defines a static method to test if the VM has continuations support.
 */
public class ContinuationSupport {
    private static final boolean SUPPORTED = isSupported0();

    private ContinuationSupport() {
    }

    /**
     * Return true if the VM has continuations support.
     */
    public static boolean isSupported() {
        return SUPPORTED;
    }

    /**
     * Ensures that VM has continuations support.
     * @throws UnsupportedOperationException if not supported
     */
    public static void ensureSupported() {
        if (!isSupported()) {
            throw new UnsupportedOperationException("VM does not support continuations");
        }
    }

    /**
     * Pins the current continuation if the VM has continuations support.
     */
    public static void pinIfSupported() {
        if (isSupported()) {
            Continuation.pin();
        }
    }

    /**
     * Unpins the current continuation if the VM has continuations support.
     */
    public static void unpinIfSupported() {
        if (isSupported()) {
            Continuation.unpin();
        }
    }

    private static native boolean isSupported0();
}