Make barcodes.dmcode.Placement thread safe

DEVSIX-1848

Author: pavel-alay

barcodes/src/main/java/com/itextpdf/barcodes/dmcode/Placement.java

@@ -44,21 +44,25 @@ This file is part of the iText (R) project.
 package com.itextpdf.barcodes.dmcode;
 
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 public class Placement {
-    private int nrow;
-    private int ncol;
-    private short[] array;
-    private static final Map<Integer, short[]> cache = new HashMap<>();
-
-    private Placement() {
+    private final int nrow;
+    private final int ncol;
+    private final short[] array;
+    private static final Map<Integer, short[]> cache = new ConcurrentHashMap<>();
+
+    private Placement(int nrow, int ncol) {
+        this.nrow = nrow;
+        this.ncol = ncol;
+        array = new short[nrow * ncol];
     }
 
 
     /**
      * Execute the placement
+     *
      * @param nrow number of rows
      * @param ncol number of columns
      * @return array containing appropriate values for ECC200
@@ -68,10 +72,7 @@ public static short[] doPlacement(int nrow, int ncol) {
         short[] pc = cache.get(key);
         if (pc != null)
             return pc;
-        Placement p = new Placement();
-        p.nrow = nrow;
-        p.ncol = ncol;
-        p.array = new short[nrow * ncol];
+        Placement p = new Placement(nrow, ncol);
         p.ecc200();
         cache.put(key, p.array);
         return p.array;
@@ -150,19 +151,19 @@ private void corner4(int chr) {
     /* "ECC200" fills an nrow x ncol array with appropriate values for ECC200 */
     private void ecc200() {
         int row, col, chr;
-            /* First, fill the array[] with invalid entries */
+        /* First, fill the array[] with invalid entries */
         Arrays.fill(array, (short) 0);
-            /* Starting in the correct location for character #1, bit 8,... */
+        /* Starting in the correct location for character #1, bit 8,... */
         chr = 1;
         row = 4;
         col = 0;
         do {
-                /* repeatedly first check for one of the special corner cases, then... */
+            /* repeatedly first check for one of the special corner cases, then... */
             if (row == nrow && col == 0) corner1(chr++);
             if (row == nrow - 2 && col == 0 && ncol % 4 != 0) corner2(chr++);
             if (row == nrow - 2 && col == 0 && ncol % 8 == 4) corner3(chr++);
             if (row == nrow + 4 && col == 2 && ncol % 8 == 0) corner4(chr++);
-                /* sweep upward diagonally, inserting successive characters,... */
+            /* sweep upward diagonally, inserting successive characters,... */
             do {
                 if (row < nrow && col >= 0 && array[row * ncol + col] == 0)
                     utah(row, col, chr++);
@@ -171,7 +172,7 @@ private void ecc200() {
             } while (row >= 0 && col < ncol);
             row += 1;
             col += 3;
-                /* & then sweep downward diagonally, inserting successive characters,... */
+            /* & then sweep downward diagonally, inserting successive characters,... */
 
             do {
                 if (row >= 0 && col < ncol && array[row * ncol + col] == 0)
@@ -181,9 +182,9 @@ private void ecc200() {
             } while (row < nrow && col >= 0);
             row += 3;
             col += 1;
-                /* ... until the entire array is scanned */
+            /* ... until the entire array is scanned */
         } while (row < nrow || col < ncol);
-            /* Lastly, if the lower righthand corner is untouched, fill in fixed pattern */
+        /* Lastly, if the lower righthand corner is untouched, fill in fixed pattern */
         if (array[nrow * ncol - 1] == 0) {
             array[nrow * ncol - 1] = array[nrow * ncol - ncol - 2] = 1;
         }

barcodes/src/test/java/com/itextpdf/barcodes/BarcodeMultiThreadingTest.java

@@ -0,0 +1,35 @@
+package com.itextpdf.barcodes;
+
+import com.itextpdf.test.annotations.type.UnitTest;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category(UnitTest.class)
+public class BarcodeMultiThreadingTest {
+
+    private static class DataMatrixThread extends Thread {
+        @Override
+        public void run() {
+            BarcodeDataMatrix bc = new BarcodeDataMatrix();
+            bc.setOptions(BarcodeDataMatrix.DM_AUTO);
+            bc.setWidth(10);
+            bc.setHeight(10);
+            int result = bc.setCode("AB01");
+
+            Assert.assertEquals(BarcodeDataMatrix.DM_NO_ERROR, result);
+        }
+    }
+
+    @Test(timeout = 10000)
+    public void test() throws InterruptedException {
+        Thread[] threads = new DataMatrixThread[20];
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new DataMatrixThread();
+            threads[i].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+    }
+}