XIDGenerator.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 * 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,
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package sun.java2d.xr;

/**
 * Class provides unused XIDs, used for creating server-side objects
 * created by the java backend.
 * It does buffering, to minimize JNI overhead.
 *
 * @author Clemens Eisserer
 */

public class XIDGenerator {
    private final static int XID_BUFFER_SIZE = 512;

    int[] xidBuffer = new int[XID_BUFFER_SIZE];
    int currentIndex = XID_BUFFER_SIZE;

    public int getNextXID() {

        if (currentIndex >= XID_BUFFER_SIZE) {
            bufferXIDs(xidBuffer, xidBuffer.length);
            currentIndex = 0;
        }

        return xidBuffer[currentIndex++];
    }

    private static native void bufferXIDs(int[] buffer, int arraySize);
}