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- /*
- * Copyright (C) 2010, 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;
- import org.eclipse.jgit.storage.pack.ObjectReuseAsIs;
-
- /**
- * Reads an {@link ObjectDatabase} for a single thread.
- * <p>
- * Readers that can support efficient reuse of pack encoded objects should also
- * implement the companion interface {@link ObjectReuseAsIs}.
- */
- public abstract class ObjectReader {
- /** Type hint indicating the caller doesn't know the type. */
- protected static final int OBJ_ANY = -1;
-
- /**
- * Construct a new reader from the same data.
- * <p>
- * Applications can use this method to build a new reader from the same data
- * source, but for an different thread.
- *
- * @return a brand new reader, using the same data source.
- */
- public abstract ObjectReader newReader();
-
- /**
- * Does the requested object exist in this database?
- *
- * @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(AnyObjectId objectId) throws IOException {
- return has(objectId, OBJ_ANY);
- }
-
- /**
- * Does the requested object exist in this database?
- *
- * @param objectId
- * identity of the object to test for existence of.
- * @param typeHint
- * hint about the type of object being requested;
- * {@link #OBJ_ANY} if the object type is not known, or does not
- * matter to the caller.
- * @return true if the specified object is stored in this database.
- * @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 boolean has(AnyObjectId objectId, int typeHint) throws IOException {
- try {
- open(objectId, typeHint);
- return true;
- } catch (MissingObjectException notFound) {
- return false;
- }
- }
-
- /**
- * Open an object from this database.
- *
- * @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(AnyObjectId objectId)
- throws MissingObjectException, IOException {
- return open(objectId, OBJ_ANY);
- }
-
- /**
- * Open an object from this database.
- *
- * @param objectId
- * identity of the object to open.
- * @param typeHint
- * hint about the type of object being requested;
- * {@link #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 abstract ObjectLoader open(AnyObjectId objectId, int typeHint)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException;
-
- /**
- * Get only the size of an object.
- * <p>
- * The default implementation of this method opens an ObjectLoader.
- * Databases are encouraged to override this if a faster access method is
- * available to them.
- *
- * @param objectId
- * identity of the object to open.
- * @param typeHint
- * hint about the type of object being requested;
- * {@link #OBJ_ANY} if the object type is not known, or does not
- * matter to the caller.
- * @return size of object in bytes.
- * @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 long getObjectSize(AnyObjectId objectId, int typeHint)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException {
- return open(objectId, typeHint).getSize();
- }
-
- /**
- * Release any resources used by this reader.
- * <p>
- * A reader that has been released can be used again, but may need to be
- * released after the subsequent usage.
- */
- public void release() {
- // Do nothing.
- }
- }
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