RebaseToOriginMaster.java

package org.dstadler.jgit.porcelain;

/*
   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 java.util.List;

import org.dstadler.jgit.helper.CookbookHelper;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.RebaseCommand;
import org.eclipse.jgit.api.RebaseCommand.InteractiveHandler;
import org.eclipse.jgit.api.RebaseResult;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.errors.IllegalTodoFileModification;
import org.eclipse.jgit.lib.RebaseTodoLine;
import org.eclipse.jgit.lib.RebaseTodoLine.Action;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.RepositoryState;

/**
 * Snippet which shows how to rebase local changes onto a remote branch.
 *
 * See also http://stackoverflow.com/questions/22945257/jgit-how-to-squash-commits
 *
 * @author dominik.stadler at gmx.at
 */
public class RebaseToOriginMaster {

    public static void main(String[] args) throws IOException, GitAPIException {
        try (Repository repository = CookbookHelper.openJGitCookbookRepository()) {
            // all refs
            try (Git git = new Git(repository)) {
                InteractiveHandler handler = new InteractiveHandler() {
                    @Override
                    public void prepareSteps(List<RebaseTodoLine> steps) {
                        // the handler receives the list of commits that are rebased, i.e. the ones on the local branch
                        for(RebaseTodoLine step : steps) {
                            // for each step, you can decide which action should be taken
                            // default is PICK
                            try {
                                // by selecting "EDIT", the rebase will stop and ask you to edit the commit-contents
                                step.setAction(Action.EDIT);
                            } catch (IllegalTodoFileModification e) {
                                throw new IllegalStateException(e);
                            }
                        }
                    }

                    @Override
                    public String modifyCommitMessage(String oldMessage) {
                        return oldMessage;
                    }
                };

                RebaseResult result = git.rebase().setUpstream("origin/master").runInteractively(handler).call();
                System.out.println("Rebase had state: " + result.getStatus() + ": " + result.getConflicts());

                // because of the "EDIT" in the InteractiveHandler, the rebase was stopped in-between
                // now you can adjust the commit and continue rebasing with setOperation(RebaseCommand.Operation.CONTINUE)
                // to use the local changes for the commit or setOperation(RebaseCommand.Operation.SKIP) to skip this
                // commit (i.e. remove it from the branch!)

                if(!result.getStatus().isSuccessful() &&
                        // sometimes the repository does not need aborting afterwards?!
                        repository.getRepositoryState() != RepositoryState.SAFE) {
                    // if rebasing stopped or failed, you can get back to the original state by running it with setOperation(RebaseCommand.Operation.ABORT)
                    result = git.rebase().setUpstream("origin/master").runInteractively(handler).setOperation(RebaseCommand.Operation.ABORT).call();
                    System.out.println("Aborted reabse with state: " + result.getStatus() + ": " + result.getConflicts());
                }
            }
        }
    }
}