jgit/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftable/RefCursor.java

/*
 * Copyright (C) 2017, Google Inc.
 * 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
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 *
 * - Redistributions of source code must retain the above copyright
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 *
 * - 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
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package org.eclipse.jgit.internal.storage.reftable;

import java.io.IOException;

import org.eclipse.jgit.lib.Ref;

/**
 * Iterator over references inside a
 * {@link org.eclipse.jgit.internal.storage.reftable.Reftable}.
 */
public abstract class RefCursor implements AutoCloseable {
	/**
	 * Check if another reference is available.
	 *
	 * @return {@code true} if there is another result.
	 * @throws java.io.IOException
	 *             references cannot be read.
	 */
	public abstract boolean next() throws IOException;

	/**
	 * Get reference at the current position.
	 *
	 * @return reference at the current position.
	 */
	public abstract Ref getRef();

	/**
	 * Whether the current reference was deleted.
	 *
	 * @return {@code true} if the current reference was deleted.
	 */
	public boolean wasDeleted() {
		Ref r = getRef();
		return r.getStorage() == Ref.Storage.NEW && r.getObjectId() == null;
	}

	/** {@inheritDoc} */
	@Override
	public abstract void close();
}