Java tutorial
/* * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> * Copyright 2013 gitblit.com. * 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. * * 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. */ package com.gitblit.servlet; import java.awt.BasicStroke; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.Stroke; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.Serializable; import java.util.ArrayList; import java.util.LinkedList; import java.util.List; import java.util.Set; import java.util.TreeSet; import javax.imageio.ImageIO; import com.google.inject.Inject; import com.google.inject.Singleton; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.Ref; import org.eclipse.jgit.lib.Repository; import org.eclipse.jgit.revplot.AbstractPlotRenderer; import org.eclipse.jgit.revplot.PlotCommit; import org.eclipse.jgit.revplot.PlotCommitList; import org.eclipse.jgit.revplot.PlotLane; import org.eclipse.jgit.revplot.PlotWalk; import org.eclipse.jgit.revwalk.RevCommit; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.gitblit.Constants; import com.gitblit.IStoredSettings; import com.gitblit.Keys; import com.gitblit.manager.IRepositoryManager; import com.gitblit.utils.JGitUtils; import com.gitblit.utils.StringUtils; /** * Handles requests for branch graphs * * @author James Moger * */ @Singleton public class BranchGraphServlet extends HttpServlet { private static final long serialVersionUID = 1L; private static final int LANE_WIDTH = 14; // must match tr.commit css height private static final int ROW_HEIGHT = 24; private static final int RIGHT_PAD = 2; private final Logger log = LoggerFactory.getLogger(getClass()); private final Stroke[] strokeCache; private IStoredSettings settings; private IRepositoryManager repositoryManager; @Inject public BranchGraphServlet(IStoredSettings settings, IRepositoryManager repositoryManager) { this.settings = settings; this.repositoryManager = repositoryManager; strokeCache = new Stroke[4]; for (int i = 1; i < strokeCache.length; i++) { strokeCache[i] = new BasicStroke(i); } } /** * Returns an url to this servlet for the specified parameters. * * @param baseURL * @param repository * @param objectId * @param numberCommits * @return an url */ public static String asLink(String baseURL, String repository, String objectId, int numberCommits) { if (baseURL.length() > 0 && baseURL.charAt(baseURL.length() - 1) == '/') { baseURL = baseURL.substring(0, baseURL.length() - 1); } return baseURL + Constants.BRANCH_GRAPH_PATH + "?r=" + repository + (objectId == null ? "" : ("&h=" + objectId)) + (numberCommits > 0 ? ("&l=" + numberCommits) : ""); } @Override protected long getLastModified(HttpServletRequest req) { String repository = req.getParameter("r"); if (StringUtils.isEmpty(repository)) { return 0; } String objectId = req.getParameter("h"); Repository r = null; try { r = repositoryManager.getRepository(repository); if (StringUtils.isEmpty(objectId)) { objectId = JGitUtils.getHEADRef(r); } ObjectId id = r.resolve(objectId); if (id == null) { return 0; } RevCommit commit = JGitUtils.getCommit(r, objectId); return JGitUtils.getCommitDate(commit).getTime(); } catch (Exception e) { log.error("Failed to determine last modified", e); return 0; } finally { if (r != null) { r.close(); } } } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { InputStream is = null; Repository r = null; PlotWalk rw = null; try { String repository = request.getParameter("r"); if (StringUtils.isEmpty(repository)) { response.setStatus(HttpServletResponse.SC_BAD_REQUEST); response.getWriter().append("Bad request"); return; } String objectId = request.getParameter("h"); String length = request.getParameter("l"); r = repositoryManager.getRepository(repository); if (r == null) { response.setStatus(HttpServletResponse.SC_BAD_REQUEST); response.getWriter().append("Bad request"); return; } rw = new PlotWalk(r); if (StringUtils.isEmpty(objectId)) { objectId = JGitUtils.getHEADRef(r); } ObjectId id = r.resolve(objectId); if (id == null) { response.setStatus(HttpServletResponse.SC_BAD_REQUEST); response.getWriter().append("Bad request"); return; } rw.markStart(rw.lookupCommit(id)); // default to the items-per-page setting, unless specified int maxCommits = settings.getInteger(Keys.web.itemsPerPage, 50); int requestedCommits = maxCommits; if (!StringUtils.isEmpty(length)) { int l = Integer.parseInt(length); if (l > 0) { requestedCommits = l; } } // fetch the requested commits plus some extra so that the last // commit displayed *likely* has correct lane assignments CommitList commitList = new CommitList(); commitList.source(rw); commitList.fillTo(2 * Math.max(requestedCommits, maxCommits)); // determine the appropriate width for the image int numLanes = 1; int numCommits = Math.min(requestedCommits, commitList.size()); if (numCommits > 1) { // determine graph width Set<String> parents = new TreeSet<String>(); for (int i = 0; i < commitList.size(); i++) { PlotCommit<Lane> commit = commitList.get(i); boolean checkLane = false; if (i < numCommits) { // commit in visible list checkLane = true; // remember parents for (RevCommit p : commit.getParents()) { parents.add(p.getName()); } } else if (parents.contains(commit.getName())) { // commit outside visible list, but it is a parent of a // commit in the visible list so we need to know it's lane // assignment checkLane = true; } if (checkLane) { int pos = commit.getLane().getPosition(); numLanes = Math.max(numLanes, pos + 1); } } } int graphWidth = numLanes * LANE_WIDTH + RIGHT_PAD; int rowHeight = ROW_HEIGHT; // create an image buffer and render the lanes BufferedImage image = new BufferedImage(graphWidth, rowHeight * numCommits, BufferedImage.TYPE_INT_ARGB); Graphics2D g = null; try { g = image.createGraphics(); g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); LanesRenderer renderer = new LanesRenderer(); for (int i = 0; i < commitList.size(); i++) { PlotCommit<Lane> commit = commitList.get(i); Graphics row = g.create(0, i * rowHeight, graphWidth, rowHeight); try { renderer.paint(row, commit, rowHeight, graphWidth); } finally { row.dispose(); row = null; } } } finally { if (g != null) { g.dispose(); g = null; } } // write the image buffer to the client response.setContentType("image/png"); if (numCommits > 1) { response.setHeader("Cache-Control", "public, max-age=60, must-revalidate"); response.setDateHeader("Last-Modified", JGitUtils.getCommitDate(commitList.get(0)).getTime()); } OutputStream os = response.getOutputStream(); ImageIO.write(image, "png", os); os.flush(); image.flush(); image = null; } catch (Exception e) { e.printStackTrace(); } finally { if (is != null) { is.close(); is = null; } if (rw != null) { rw.dispose(); rw = null; } if (r != null) { r.close(); r = null; } } } private Stroke stroke(final int width) { if (width < strokeCache.length) return strokeCache[width]; return new BasicStroke(width); } static class CommitList extends PlotCommitList<Lane> { final List<Color> laneColors; final LinkedList<Color> colors; CommitList() { laneColors = new ArrayList<Color>(); laneColors.add(new Color(133, 166, 214)); laneColors.add(new Color(221, 205, 93)); laneColors.add(new Color(199, 134, 57)); laneColors.add(new Color(131, 150, 98)); laneColors.add(new Color(197, 123, 127)); laneColors.add(new Color(139, 136, 140)); laneColors.add(new Color(48, 135, 144)); laneColors.add(new Color(190, 93, 66)); laneColors.add(new Color(143, 163, 54)); laneColors.add(new Color(180, 148, 74)); laneColors.add(new Color(101, 101, 217)); laneColors.add(new Color(72, 153, 119)); laneColors.add(new Color(23, 101, 160)); laneColors.add(new Color(132, 164, 118)); laneColors.add(new Color(255, 230, 59)); laneColors.add(new Color(136, 176, 70)); laneColors.add(new Color(255, 138, 1)); laneColors.add(new Color(123, 187, 95)); laneColors.add(new Color(233, 88, 98)); laneColors.add(new Color(93, 158, 254)); laneColors.add(new Color(175, 215, 0)); laneColors.add(new Color(140, 134, 142)); laneColors.add(new Color(232, 168, 21)); laneColors.add(new Color(0, 172, 191)); laneColors.add(new Color(251, 58, 4)); laneColors.add(new Color(63, 64, 255)); laneColors.add(new Color(27, 194, 130)); laneColors.add(new Color(0, 104, 183)); colors = new LinkedList<Color>(); repackColors(); } private void repackColors() { colors.addAll(laneColors); } @Override protected Lane createLane() { final Lane lane = new Lane(); if (colors.isEmpty()) repackColors(); lane.color = colors.removeFirst(); return lane; } @Override protected void recycleLane(final Lane lane) { colors.add(lane.color); } } static class Lane extends PlotLane { private static final long serialVersionUID = 1L; Color color; @Override public boolean equals(Object o) { return super.equals(o) && color.equals(((Lane) o).color); } @Override public int hashCode() { return super.hashCode() ^ color.hashCode(); } } class LanesRenderer extends AbstractPlotRenderer<Lane, Color> implements Serializable { private static final long serialVersionUID = 1L; final Color commitDotFill = new Color(220, 220, 220); final Color commitDotOutline = new Color(110, 110, 110); transient Graphics2D g; void paint(Graphics in, PlotCommit<Lane> commit, int h, int w) { g = (Graphics2D) in.create(); try { if (commit != null) paintCommit(commit, h); } finally { g.dispose(); g = null; } } @Override protected void drawLine(Color color, int x1, int y1, int x2, int y2, int width) { if (y1 == y2) { x1 -= width / 2; x2 -= width / 2; } else if (x1 == x2) { y1 -= width / 2; y2 -= width / 2; } g.setColor(color); g.setStroke(stroke(width)); g.drawLine(x1, y1, x2, y2); } @Override protected void drawCommitDot(int x, int y, int w, int h) { g.setColor(commitDotFill); g.setStroke(strokeCache[2]); g.fillOval(x + 2, y + 1, w - 2, h - 2); g.setColor(commitDotOutline); g.drawOval(x + 2, y + 1, w - 2, h - 2); } @Override protected void drawBoundaryDot(int x, int y, int w, int h) { drawCommitDot(x, y, w, h); } @Override protected void drawText(String msg, int x, int y) { } @Override protected Color laneColor(Lane myLane) { return myLane != null ? myLane.color : Color.black; } @Override protected int drawLabel(int x, int y, Ref ref) { return 0; } } }