Java tutorial
/* * Copyright (C) 2010, Google Inc. * Copyright (C) 2008, 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.lib; import org.eclipse.jgit.annotations.NonNull; import org.eclipse.jgit.annotations.Nullable; /** * A {@link org.eclipse.jgit.lib.Ref} that points directly at an * {@link org.eclipse.jgit.lib.ObjectId}. */ public abstract class ObjectIdRef implements Ref { /** Any reference whose peeled value is not yet known. */ public static class Unpeeled extends ObjectIdRef { /** * Create a new ref pairing. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate * a ref that does not exist yet. */ public Unpeeled(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id) { super(st, name, id, UNDEFINED_UPDATE_INDEX); } /** * Create a new ref pairing with update index. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate * a ref that does not exist yet. * @param updateIndex * number increasing with each update to the reference. * @since 5.3 */ public Unpeeled(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id, long updateIndex) { super(st, name, id, updateIndex); } @Override @Nullable public ObjectId getPeeledObjectId() { return null; } @Override public boolean isPeeled() { return false; } } /** An annotated tag whose peeled object has been cached. */ public static class PeeledTag extends ObjectIdRef { private final ObjectId peeledObjectId; /** * Create a new ref pairing. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. * @param p * the first non-tag object that tag {@code id} points to. */ public PeeledTag(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id, @NonNull ObjectId p) { super(st, name, id, UNDEFINED_UPDATE_INDEX); peeledObjectId = p; } /** * Create a new ref pairing with update index. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate * a ref that does not exist yet. * @param p * the first non-tag object that tag {@code id} points to. * @param updateIndex * number increasing with each update to the reference. * @since 5.3 */ public PeeledTag(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id, @NonNull ObjectId p, long updateIndex) { super(st, name, id, updateIndex); peeledObjectId = p; } @Override @NonNull public ObjectId getPeeledObjectId() { return peeledObjectId; } @Override public boolean isPeeled() { return true; } } /** A reference to a non-tag object coming from a cached source. */ public static class PeeledNonTag extends ObjectIdRef { /** * Create a new ref pairing. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate * a ref that does not exist yet. */ public PeeledNonTag(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id) { super(st, name, id, UNDEFINED_UPDATE_INDEX); } /** * Create a new ref pairing with update index. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate * a ref that does not exist yet. * @param updateIndex * number increasing with each update to the reference. * @since 5.3 */ public PeeledNonTag(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id, long updateIndex) { super(st, name, id, updateIndex); } @Override @Nullable public ObjectId getPeeledObjectId() { return null; } @Override public boolean isPeeled() { return true; } } private final String name; private final Storage storage; private final ObjectId objectId; private final long updateIndex; /** * Create a new ref pairing. * * @param st * method used to store this ref. * @param name * name of this ref. * @param id * current value of the ref. May be {@code null} to indicate a * ref that does not exist yet. * @param updateIndex * number that increases with each ref update. Set to -1 if the * storage doesn't support versioning. * @since 5.3 */ protected ObjectIdRef(@NonNull Storage st, @NonNull String name, @Nullable ObjectId id, long updateIndex) { this.name = name; this.storage = st; this.objectId = id; this.updateIndex = updateIndex; } /** {@inheritDoc} */ @Override @NonNull public String getName() { return name; } /** {@inheritDoc} */ @Override public boolean isSymbolic() { return false; } /** {@inheritDoc} */ @Override @NonNull public Ref getLeaf() { return this; } /** {@inheritDoc} */ @Override @NonNull public Ref getTarget() { return this; } /** {@inheritDoc} */ @Override @Nullable public ObjectId getObjectId() { return objectId; } /** {@inheritDoc} */ @Override @NonNull public Storage getStorage() { return storage; } /** * {@inheritDoc} * @since 5.3 */ @Override public long getUpdateIndex() { if (updateIndex == UNDEFINED_UPDATE_INDEX) { throw new UnsupportedOperationException(); } return updateIndex; } /** {@inheritDoc} */ @NonNull @Override public String toString() { StringBuilder r = new StringBuilder(); r.append("Ref["); //$NON-NLS-1$ r.append(getName()); r.append('='); r.append(ObjectId.toString(getObjectId())); r.append('('); r.append(updateIndex); // Print value, even if -1 r.append(")]"); //$NON-NLS-1$ return r.toString(); } }