diff --git a/source/net/yacy/visualization/CircleTool.java b/source/net/yacy/visualization/CircleTool.java
index 87bbfbef5..def9c6d51 100644
--- a/source/net/yacy/visualization/CircleTool.java
+++ b/source/net/yacy/visualization/CircleTool.java
@@ -24,17 +24,28 @@ import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
public class CircleTool {
- private static List<int[]> circles = new ArrayList<>();
+ /** Cache of calculated circles */
+ private static final List<int[]> CIRCLES_CACHE = new ArrayList<>();
+
+ /** Synchronization lock for cache access */
+ private static final ReentrantLock CIRCLES_CACHE_LOCK = new ReentrantLock();
public static void clearcache() {
- circles.clear();
+ CIRCLES_CACHE_LOCK.lock();
+ try {
+ CIRCLES_CACHE.clear();
+ } finally {
+ CIRCLES_CACHE_LOCK.unlock();
+ }
}
- private static int[] getCircleCoords(final short radius) {
+ private static int[] getCircleCoords(final short radius, final List<int[]> circles) {
if (radius - 1 < circles.size()) return circles.get(radius - 1);
// read some lines from known circles
@@ -90,10 +101,23 @@ public class CircleTool {
}
public static void circle(final RasterPlotter matrix, final int xc, final int yc, final int radius, final int intensity) {
- if (radius == 0) {
- //matrix.plot(xc, yc, 100);
- } else {
- final int[] c = getCircleCoords((short) radius);
+ if (radius != 0) {
+ final int[] c;
+ try {
+ if (CIRCLES_CACHE_LOCK.tryLock(1, TimeUnit.SECONDS)) {
+ try {
+ c = getCircleCoords((short) radius, CIRCLES_CACHE);
+ } finally {
+ CIRCLES_CACHE_LOCK.unlock();
+ }
+ } else {
+ /* Cache is too busy : let's calculate without it */
+ c = getCircleCoords((short) radius, new ArrayList<>());
+ }
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt(); // preserve thread interrupted state
+ return;
+ }
short x, y;
short limit = (short) c.length;
int co;
@@ -116,11 +140,23 @@ public class CircleTool {
while (fromArc < 0 ) fromArc +=360;
while ( toArc > 360) toArc -=360;
while ( toArc < 0 ) toArc +=360;
- if (radius == 0) {
- //matrix.plot(xc, yc, 100);
- } else {
- int[] c = getCircleCoords((short) radius);
- if (c == null) c = getCircleCoords((short) radius);
+ if (radius != 0) {
+ final int[] c;
+ try {
+ if (CIRCLES_CACHE_LOCK.tryLock(1, TimeUnit.SECONDS)) {
+ try {
+ c = getCircleCoords((short) radius, CIRCLES_CACHE);
+ } finally {
+ CIRCLES_CACHE_LOCK.unlock();
+ }
+ } else {
+ /* Cache is too busy : let's calculate without it */
+ c = getCircleCoords((short) radius, new ArrayList<>());
+ }
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt(); // preserve thread interrupted state
+ return;
+ }
final short q = (short) c.length;
final short q2 = (short) (q * 2);
final short q3 = (short) (q * 3);
diff --git a/test/java/net/yacy/visualization/CircleToolTest.java b/test/java/net/yacy/visualization/CircleToolTest.java
new file mode 100644
index 000000000..14fda8c23
--- /dev/null
+++ b/test/java/net/yacy/visualization/CircleToolTest.java
@@ -0,0 +1,119 @@
+// CircleToolTest.java
+// Copyright 2018 by luccioman; https://github.com/luccioman
+//
+// This is a part of YaCy, a peer-to-peer based web search engine
+//
+// LICENSE
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program 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 General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package net.yacy.visualization;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import org.bouncycastle.util.Arrays;
+import org.junit.Assert;
+import org.junit.Test;
+
+import net.yacy.peers.graphics.EncodedImage;
+
+/**
+ * Unit tests for the {@link CircleTool} class.
+ */
+public class CircleToolTest {
+
+ /**
+ * Check circle function consistency when run on multiple concurrent threads.
+ *
+ * @throws Exception when an unexpected error occurred
+ */
+ @Test
+ public void testCircleConcurrentConsistency() throws Exception {
+ final int concurrency = 20;
+ final int side = 600;
+ final String ext = "png";
+
+ final Callable<byte[]> drawTask = () -> {
+ final RasterPlotter raster = new RasterPlotter(side, side, RasterPlotter.DrawMode.MODE_SUB, "FFFFFF");
+ for (int radius = side / 4; radius < side / 2; radius++) {
+ raster.setColor(RasterPlotter.GREEN);
+ CircleTool.circle(raster, side / 2, side / 2, radius, 100);
+ raster.setColor(RasterPlotter.RED);
+ CircleTool.circle(raster, side / 2, side / 2, radius, 0, 45);
+ }
+
+ final EncodedImage image = new EncodedImage(raster, ext, true);
+ return image.getImage().getBytes();
+ };
+
+ /* Generate a reference image without concurrency */
+ CircleTool.clearcache();
+ final byte[] refImageBytes = drawTask.call();
+
+ /* Write the reference image to the file system to enable manual visual check */
+ final Path outputPath = Paths.get(System.getProperty("java.io.tmpdir", ""), "CircleToolTest." + ext);
+ try {
+ Files.write(outputPath, refImageBytes);
+ System.out.println("Wrote CircleTool.circle() test image to file " + outputPath.toAbsolutePath());
+ } catch (final IOException e) {
+ /*
+ * Even if output file writing failed we do not make the test fail as this is
+ * not the purpose of the test
+ */
+ e.printStackTrace();
+ }
+
+ /*
+ * Generate the same image multiple times in concurrent threads without initial
+ * cache
+ */
+ CircleTool.clearcache();
+ final ExecutorService executor = Executors.newFixedThreadPool(concurrency);
+ final ArrayList<Future<byte[]>> futures = new ArrayList<>();
+ for (int i = 0; i < concurrency; i++) {
+ futures.add(executor.submit(drawTask));
+ }
+ try {
+ for (final Future<byte[]> future : futures) {
+ /* Check that all concurrently generated images are equal to the reference */
+ final byte[] imageBytes = future.get();
+ if (!Arrays.areEqual(refImageBytes, imageBytes)) {
+ /* Write the image in error to file system to enable manual visual check */
+ final Path errOutputPath = Paths.get(System.getProperty("java.io.tmpdir", ""),
+ "CircleToolTestError." + ext);
+ try {
+ Files.write(errOutputPath, imageBytes);
+ System.out.println(
+ "Wrote CircleTool.circle() error image to file " + errOutputPath.toAbsolutePath());
+ } catch (final IOException e) {
+ e.printStackTrace();
+ }
+ Assert.fail();
+ }
+ }
+ } finally {
+ executor.shutdown();
+ }
+ }
+
+}