package org.dstadler.jgit.api;
/*
Copyright 2013, 2014 Dominik Stadler
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
import java.io.IOException;
import org.dstadler.jgit.helper.CookbookHelper;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.filter.PathFilter;
/**
* Snippet which shows how to use RevWalk and TreeWalk to read the contents
* of a specific file from a specific commit.
*
* @author dominik.stadler at gmx.at
*/
public class ReadFileFromCommit {
public static void main(String[] args) throws IOException, GitAPIException {
Repository repository = CookbookHelper.openJGitCookbookRepository();
// find the HEAD
ObjectId lastCommitId = repository.resolve(Constants.HEAD);
// a RevWalk allows to walk over commits based on some filtering that is defined
RevWalk revWalk = new RevWalk(repository);
RevCommit commit = revWalk.parseCommit(lastCommitId);
// and using commit's tree find the path
RevTree tree = commit.getTree();
System.out.println("Having tree: " + tree);
// now try to find a specific file
TreeWalk treeWalk = new TreeWalk(repository);
treeWalk.addTree(tree);
treeWalk.setRecursive(true);
treeWalk.setFilter(PathFilter.create("README.md"));
if (!treeWalk.next()) {
throw new IllegalStateException("Did not find expected file 'README.md'");
}
ObjectId objectId = treeWalk.getObjectId(0);
ObjectLoader loader = repository.open(objectId);
// and then one can the loader to read the file
loader.copyTo(System.out);
revWalk.dispose();
repository.close();
}
}