Java tutorial
/*==========================================================================*\ | $Id: GitTreeIterator.java,v 1.2 2011/11/08 14:06:07 aallowat Exp $ |*-------------------------------------------------------------------------*| | Copyright (C) 2011 Virginia Tech | | This file is part of Web-CAT. | | Web-CAT is free software; you can redistribute it and/or modify | it under the terms of the GNU Affero General Public License as published | by the Free Software Foundation; either version 3 of the License, or | (at your option) any later version. | | Web-CAT is distributed in the hope that it will be useful, | but WITHOUT ANY WARRANTY; without even the implied warranty of | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | GNU General Public License for more details. | | You should have received a copy of the GNU Affero General Public License | along with Web-CAT; if not, see <http://www.gnu.org/licenses/>. \*==========================================================================*/ package org.webcat.core.git; import java.io.IOException; import java.util.Iterator; import org.eclipse.jgit.lib.Constants; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.ObjectReader; import org.eclipse.jgit.revwalk.RevWalk; import org.eclipse.jgit.treewalk.CanonicalTreeParser; import org.eclipse.jgit.treewalk.TreeWalk; import com.webobjects.foundation.NSArray; import com.webobjects.foundation.NSMutableArray; //------------------------------------------------------------------------- /** * An iterator that iterates over a Git tree or commit object. * * @author Tony Allevato * @author Last changed by $Author: aallowat $ * @version $Revision: 1.2 $, $Date: 2011/11/08 14:06:07 $ */ public class GitTreeIterator implements Iterator<GitTreeEntry>, Iterable<GitTreeEntry> { //~ Constructors .......................................................... // ---------------------------------------------------------- /** * Creates a new non-recursive {@code GitTreeIterator} for the specified * tree or commit object. * * @param repository the repository * @param treeOrCommitId the id of the tree or commit object */ public GitTreeIterator(GitRepository repository, ObjectId treeOrCommitId) { this(repository, treeOrCommitId, null); } // ---------------------------------------------------------- /** * Creates a new non-recursive {@code GitTreeIterator} for the specified * tree or commit object. * * @param repository the repository * @param treeOrCommitId the id of the tree or commit object * @param pathPrefix a prefix to be prepended to the paths of the returned * entries, or null */ public GitTreeIterator(GitRepository repository, ObjectId treeOrCommitId, String pathPrefix) { this(repository, treeOrCommitId, false); this.pathPrefix = pathPrefix; } // ---------------------------------------------------------- /** * Creates a new {@code GitTreeIterator} for the specified tree or commit * object. * * @param repository the repository * @param treeOrCommitId the id of the tree or commit object * @param recursive true if the iterator should be recursive, otherwise * false */ public GitTreeIterator(GitRepository repository, ObjectId treeOrCommitId, boolean recursive) { this.repository = repository; this.recursive = recursive; int type = repository.typeOfObject(treeOrCommitId); if (type == Constants.OBJ_TREE) { initializeFromTree(treeOrCommitId); } else if (type == Constants.OBJ_COMMIT || type == Constants.OBJ_TAG) { initializeFromCommit(treeOrCommitId); } else { treeWalk = null; } } //~ Methods ............................................................... // ---------------------------------------------------------- /** * Gets a value indicating whether or not the iterator is recursive. * * @return true if the iterator is recursive, otherwise false */ public boolean isRecursive() { return recursive; } // ---------------------------------------------------------- /** * Gets an array of {@link GitTreeEntry} objects that represent the entire * contents of the tree. This method exhausts the iterator and may only be * called on a newly-created iterator; it may not be called once * {@link #next()} has been called. * * @return an {@code NSArray} containing all of the {@link GitTreeEntry} * objects in the tree */ public NSArray<GitTreeEntry> allEntries() { if (nextWasCalled) { throw new IllegalStateException("allEntries() cannot be called " + "once next() has been called."); } NSMutableArray<GitTreeEntry> entries = new NSMutableArray<GitTreeEntry>(); for (GitTreeEntry entry : this) { entries.addObject(entry); } GitUtilities.sortEntries(entries); return entries; } // ---------------------------------------------------------- /** * Releases any resources in use by the iterator. */ public void release() { if (revWalk != null) { revWalk.release(); } if (treeWalk != null) { treeWalk.release(); } } // ---------------------------------------------------------- /** * Returns this iterator. This method is provided so that the iterator * itself can be used in a for-each loop. * * @return this iterator */ public Iterator<GitTreeEntry> iterator() { return this; } // ---------------------------------------------------------- /** * Gets a value indicating whether or not the iterator has another entry. * * @return true if the iterator has another entry, or false if it does not */ public boolean hasNext() { try { return treeWalk != null && treeWalk.next(); } catch (IOException e) { return false; } } // ---------------------------------------------------------- /** * Gets the next entry in the tree. * * @return a {@link GitTreeEntry} representing the next entry in the tree */ public GitTreeEntry next() { nextWasCalled = true; return GitTreeEntry.fromTreeWalk(treeWalk, repository, pathPrefix); } // ---------------------------------------------------------- /** * Removal is not supported by {@code GitTreeIterator}. * * @throws UnsupportedOperationException */ public void remove() { throw new UnsupportedOperationException("remove() is not supported on " + "GitTreeIterators."); } // ---------------------------------------------------------- /** * Initializes the iterator from an object ID that represents a tree. * * @param treeId the tree id */ private void initializeFromTree(ObjectId treeId) { treeWalk = new TreeWalk(repository.repository()); treeWalk.setRecursive(recursive); try { treeWalk.addTree(treeId); } catch (IOException e) { // Do nothing. } } // ---------------------------------------------------------- /** * Initializes the iterator from an object ID that represents a commit. * * @param treeId the commit id */ private void initializeFromCommit(ObjectId commitId) { revWalk = new RevWalk(repository.repository()); treeWalk = new TreeWalk(repository.repository()); treeWalk.setRecursive(recursive); try { CanonicalTreeParser parser = new CanonicalTreeParser(); ObjectReader reader = repository.repository().newObjectReader(); parser.reset(reader, revWalk.parseTree(commitId)); treeWalk.addTree(parser); } catch (IOException e) { // Do nothing. } } //~ Static/instance variables ............................................. private GitRepository repository; private String pathPrefix; private boolean recursive; private boolean nextWasCalled; private TreeWalk treeWalk; private RevWalk revWalk; }