Java tutorial
/* * Copyright (C) 2008, 2014 Shawn O. Pearce <spearce@spearce.org> * and other copyright owners as documented in the project's IP log. * * This program and the accompanying materials are made available * under the terms of the Eclipse Distribution License v1.0 which * accompanies this distribution, is reproduced below, and is * available at http://www.eclipse.org/org/documents/edl-v10.php * * 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 Eclipse Foundation, Inc. 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 THE COPYRIGHT OWNER OR * CONTRIBUTORS 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 org.eclipse.jgit.revplot; import org.eclipse.jgit.lib.AnyObjectId; import org.eclipse.jgit.lib.Ref; import org.eclipse.jgit.revwalk.RevCommit; /** * A commit reference to a commit in the DAG. * * @param <L> * type of lane being used by the plotter. * @see PlotCommitList */ public class PlotCommit<L extends PlotLane> extends RevCommit { static final PlotCommit[] NO_CHILDREN = {}; static final PlotLane[] NO_LANES = {}; static final Ref[] NO_REFS = {}; PlotLane[] forkingOffLanes; PlotLane[] passingLanes; PlotLane[] mergingLanes; PlotLane lane; PlotCommit[] children; Ref[] refs; /** * Create a new commit. * * @param id * the identity of this commit. */ protected PlotCommit(AnyObjectId id) { super(id); forkingOffLanes = NO_LANES; passingLanes = NO_LANES; mergingLanes = NO_LANES; children = NO_CHILDREN; refs = NO_REFS; } void addForkingOffLane(PlotLane f) { forkingOffLanes = addLane(f, forkingOffLanes); } void addPassingLane(PlotLane c) { passingLanes = addLane(c, passingLanes); } void addMergingLane(PlotLane m) { mergingLanes = addLane(m, mergingLanes); } private static PlotLane[] addLane(PlotLane l, PlotLane[] lanes) { final int cnt = lanes.length; switch (cnt) { case 0: lanes = new PlotLane[] { l }; break; case 1: lanes = new PlotLane[] { lanes[0], l }; break; default: final PlotLane[] n = new PlotLane[cnt + 1]; System.arraycopy(lanes, 0, n, 0, cnt); n[cnt] = l; lanes = n; break; } return lanes; } void addChild(PlotCommit c) { final int cnt = children.length; switch (cnt) { case 0: children = new PlotCommit[] { c }; break; case 1: if (!c.getId().equals(children[0].getId())) children = new PlotCommit[] { children[0], c }; break; default: for (PlotCommit pc : children) if (c.getId().equals(pc.getId())) return; final PlotCommit[] n = new PlotCommit[cnt + 1]; System.arraycopy(children, 0, n, 0, cnt); n[cnt] = c; children = n; break; } } /** * Get the number of child commits listed in this commit. * * @return number of children; always a positive value but can be 0. */ public final int getChildCount() { return children.length; } /** * Get the nth child from this commit's child list. * * @param nth * child index to obtain. Must be in the range 0 through * {@link #getChildCount()}-1. * @return the specified child. * @throws java.lang.ArrayIndexOutOfBoundsException * an invalid child index was specified. */ public final PlotCommit getChild(int nth) { return children[nth]; } /** * Determine if the given commit is a child (descendant) of this commit. * * @param c * the commit to test. * @return true if the given commit built on top of this commit. */ public final boolean isChild(PlotCommit c) { for (PlotCommit a : children) if (a == c) return true; return false; } /** * Get the number of refs for this commit. * * @return number of refs; always a positive value but can be 0. */ public final int getRefCount() { return refs.length; } /** * Get the nth Ref from this commit's ref list. * * @param nth * ref index to obtain. Must be in the range 0 through * {@link #getRefCount()}-1. * @return the specified ref. * @throws java.lang.ArrayIndexOutOfBoundsException * an invalid ref index was specified. */ public final Ref getRef(int nth) { return refs[nth]; } /** * Obtain the lane this commit has been plotted into. * * @return the assigned lane for this commit. */ @SuppressWarnings("unchecked") public final L getLane() { return (L) lane; } /** {@inheritDoc} */ @Override public void reset() { forkingOffLanes = NO_LANES; passingLanes = NO_LANES; mergingLanes = NO_LANES; children = NO_CHILDREN; lane = null; super.reset(); } }