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- /*
- * Copyright (C) 2009, 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
- * 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 java.io.IOException;
-
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.errors.MissingObjectException;
-
- /**
- * Abstraction of arbitrary object storage.
- * <p>
- * An object database stores one or more Git objects, indexed by their unique
- * {@link ObjectId}.
- */
- public abstract class ObjectDatabase {
- /** Initialize a new database instance for access. */
- protected ObjectDatabase() {
- // Protected to force extension.
- }
-
- /**
- * Does this database exist yet?
- *
- * @return true if this database is already created; false if the caller
- * should invoke {@link #create()} to create this database location.
- */
- public boolean exists() {
- return true;
- }
-
- /**
- * Initialize a new object database at this location.
- *
- * @throws IOException
- * the database could not be created.
- */
- public void create() throws IOException {
- // Assume no action is required.
- }
-
- /**
- * Create a new {@code ObjectInserter} to insert new objects.
- * <p>
- * The returned inserter is not itself thread-safe, but multiple concurrent
- * inserter instances created from the same {@code ObjectDatabase} must be
- * thread-safe.
- *
- * @return writer the caller can use to create objects in this database.
- */
- public abstract ObjectInserter newInserter();
-
- /**
- * Create a new {@code ObjectReader} to read existing objects.
- * <p>
- * The returned reader is not itself thread-safe, but multiple concurrent
- * reader instances created from the same {@code ObjectDatabase} must be
- * thread-safe.
- *
- * @return reader the caller can use to load objects from this database.
- */
- public abstract ObjectReader newReader();
-
- /**
- * Close any resources held by this database.
- */
- public abstract void close();
-
- /**
- * Does the requested object exist in this database?
- * <p>
- * This is a one-shot call interface which may be faster than allocating a
- * {@link #newReader()} to perform the lookup.
- *
- * @param objectId
- * identity of the object to test for existence of.
- * @return true if the specified object is stored in this database.
- * @throws IOException
- * the object store cannot be accessed.
- */
- public boolean has(final AnyObjectId objectId) throws IOException {
- try (final ObjectReader or = newReader()) {
- return or.has(objectId);
- }
- }
-
- /**
- * Open an object from this database.
- * <p>
- * This is a one-shot call interface which may be faster than allocating a
- * {@link #newReader()} to perform the lookup.
- *
- * @param objectId
- * identity of the object to open.
- * @return a {@link ObjectLoader} for accessing the object.
- * @throws MissingObjectException
- * the object does not exist.
- * @throws IOException
- * the object store cannot be accessed.
- */
- public ObjectLoader open(final AnyObjectId objectId)
- throws IOException {
- return open(objectId, ObjectReader.OBJ_ANY);
- }
-
- /**
- * Open an object from this database.
- * <p>
- * This is a one-shot call interface which may be faster than allocating a
- * {@link #newReader()} to perform the lookup.
- *
- * @param objectId
- * identity of the object to open.
- * @param typeHint
- * hint about the type of object being requested, e.g.
- * {@link Constants#OBJ_BLOB}; {@link ObjectReader#OBJ_ANY} if
- * the object type is not known, or does not matter to the
- * caller.
- * @return a {@link ObjectLoader} for accessing the object.
- * @throws MissingObjectException
- * the object does not exist.
- * @throws IncorrectObjectTypeException
- * typeHint was not OBJ_ANY, and the object's actual type does
- * not match typeHint.
- * @throws IOException
- * the object store cannot be accessed.
- */
- public ObjectLoader open(AnyObjectId objectId, int typeHint)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException {
- try (final ObjectReader or = newReader()) {
- return or.open(objectId, typeHint);
- }
- }
-
- /**
- * Create a new cached database instance over this database. This instance might
- * optimize queries by caching some information about database. So some modifications
- * done after instance creation might fail to be noticed.
- *
- * @return new cached database instance
- */
- public ObjectDatabase newCachedDatabase() {
- return this;
- }
- }
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