All Downloads are FREE. Search and download functionalities are using the official Maven repository.

io.sirix.axis.concurrent.ConcurrentIntersectAxis Maven / Gradle / Ivy

Go to download

SirixDB is a hybrid on-disk and in-memory document oriented, versioned database system. It has a lightweight buffer manager, stores everything in a huge persistent and durable tree and allows efficient reconstruction of every revision. Furthermore, SirixDB implements change tracking, diffing and supports time travel queries.

There is a newer version: 0.11.0
Show newest version
/**
 * Copyright (c) 2011, University of Konstanz, Distributed Systems Group All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met: * Redistributions of source code must retain the
 * above copyright notice, this list of conditions and the following disclaimer. * Redistributions
 * in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * * Neither the name of the University of Konstanz nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL  BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package io.sirix.axis.concurrent;

import io.sirix.api.Axis;
import io.sirix.api.NodeCursor;
import io.sirix.api.NodeReadOnlyTrx;
import io.sirix.axis.AbstractAxis;
import io.sirix.settings.Fixed;

/**
 * 

* Computes concurrently and returns an intersection of two operands. This axis takes two node * sequences as operands and returns a sequence containing all the nodes that occur in both * operands. The result is in doc order and duplicate free. *

*/ public final class ConcurrentIntersectAxis extends AbstractAxis { /** First operand sequence. */ private final ConcurrentAxis op1; /** Second operand sequence. */ private final ConcurrentAxis op2; /** Is axis called for the first time? */ private boolean first; /** Current result of the 1st axis */ private long currentResult1; /** Current result of the 2nd axis. */ private long currentResult2; /** * Constructor. Initializes the internal state. * * @param rtx exclusive (immutable) trx to iterate with. * @param operand1 first operand * @param operand2 second operand * @throws NullPointerException if {@code rtx}, {@code operand1} or {@code operand2} is {@code null} */ public ConcurrentIntersectAxis(final R rtx, final Axis operand1, final Axis operand2) { super(rtx); op1 = new ConcurrentAxis<>(rtx, operand1); op2 = new ConcurrentAxis<>(rtx, operand2); first = true; currentResult1 = Fixed.NULL_NODE_KEY.getStandardProperty(); currentResult2 = Fixed.NULL_NODE_KEY.getStandardProperty(); } @Override public synchronized void reset(final long nodeKey) { super.reset(nodeKey); if (op1 != null) { op1.reset(nodeKey); } if (op2 != null) { op2.reset(nodeKey); } first = true; currentResult1 = Fixed.NULL_NODE_KEY.getStandardProperty(); currentResult2 = Fixed.NULL_NODE_KEY.getStandardProperty(); } @Override protected long nextKey() { if (first) { first = false; currentResult1 = Util.getNext(op1); currentResult2 = Util.getNext(op2); } final long nodeKey; // if 1st axis has a result left that is not contained in the 2nd it is // returned while (!op1.isFinished()) { while (!op2.isFinished()) { // if both results are not equal get next values while (currentResult1 != currentResult2 && !op1.isFinished() && !op2.isFinished()) { // get next result from 1st axis, if current is smaller than // 2nd while (currentResult1 < currentResult2 && !op1.isFinished() && !op2.isFinished()) { currentResult1 = Util.getNext(op1); } // get next result from 2nd axis if current is smaller than // 1st while (currentResult1 > currentResult2 && !op1.isFinished() && !op2.isFinished()) { currentResult2 = Util.getNext(op2); } } if (!op1.isFinished() && !op2.isFinished()) { // if both results are equal return it assert (currentResult1 == currentResult2); nodeKey = currentResult1; if (Util.isValid(nodeKey)) { currentResult1 = Util.getNext(op1); currentResult2 = Util.getNext(op2); return nodeKey; } // should never come here! throw new IllegalStateException(nodeKey + " is not valid!"); } break; } break; } return done(); } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy