add concurrent test

Signed-off-by: Kaushal Kumar <ravi.kaushal97@gmail.com>

Author: kaushalmahi12

libs/autotagging-commons/src/test/java/org/opensearch/rule/storage/AttributeValueStoreTests.java

@@ -11,9 +11,15 @@
 import org.apache.commons.collections4.trie.PatriciaTrie;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
 public class AttributeValueStoreTests extends OpenSearchTestCase {
 
     AttributeValueStore<String, String> subjectUnderTest;
+    final static String ALPHA_NUMERIC = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+    final static Random random = new Random();
 
     public void setUp() throws Exception {
         super.setUp();
@@ -50,4 +56,73 @@ public void testClear() {
         subjectUnderTest.clear();
         assertEquals(0, subjectUnderTest.size());
     }
+
+    public void testConcurrentUpdatesAndReads() {
+        final List<String> randomStrings = new ArrayList<>();
+        for (int i = 0; i < 100; i++) {
+            randomStrings.add(generateRandom(20));
+        }
+        List<Thread> readerThreads = new ArrayList<>();
+        List<Thread> writerThreads = new ArrayList<>();
+        for (int i = 0; i < 10; i++) {
+            readerThreads.add(new AttributeValueStoreReader(subjectUnderTest, randomStrings));
+            writerThreads.add(new AttributeValueStoreWriter(subjectUnderTest, randomStrings));
+        }
+
+        for (int ii = 0; ii < 10; ii++) {
+            readerThreads.get(ii).start();
+            writerThreads.get(ii).start();
+        }
+    }
+
+    public static String generateRandom(int maxLength) {
+        int length = random.nextInt(maxLength) + 1; // +1 to avoid length 0
+        StringBuilder sb = new StringBuilder(length);
+        for (int i = 0; i < length; i++) {
+            sb.append(ALPHA_NUMERIC.charAt(random.nextInt(ALPHA_NUMERIC.length())));
+        }
+        return sb.toString();
+    }
+
+    private static class AttributeValueStoreReader extends Thread {
+        private final AttributeValueStore<String, String> subjectUnderTest;
+        private final List<String> toReadKeys;
+
+        public AttributeValueStoreReader(AttributeValueStore<String, String> subjectUnderTest, List<String> toReadKeys) {
+            super();
+            this.subjectUnderTest = subjectUnderTest;
+            this.toReadKeys = toReadKeys;
+        }
+
+        @Override
+        public void run() {
+            try {
+                Thread.sleep(random().nextInt(100));
+                for (String key : toReadKeys) {
+                    subjectUnderTest.get(key);
+                }
+            } catch (InterruptedException e) {}
+        }
+    }
+
+    private static class AttributeValueStoreWriter extends Thread {
+        private final AttributeValueStore<String, String> subjectUnderTest;
+        private final List<String> toWriteKeys;
+
+        public AttributeValueStoreWriter(AttributeValueStore<String, String> subjectUnderTest, List<String> toWriteKeys) {
+            super();
+            this.subjectUnderTest = subjectUnderTest;
+            this.toWriteKeys = toWriteKeys;
+        }
+
+        @Override
+        public void run() {
+            try {
+                Thread.sleep(random().nextInt(100));
+                for (String key : toWriteKeys) {
+                    subjectUnderTest.put(key, key);
+                }
+            } catch (InterruptedException e) {}
+        }
+    }
 }