Merge pull request stleary#524 from viveksacademia4git/i516-JSONArray-ConstructParam-InitCapacity

Development for stleary#516 completed with rebased repository

Author: stleary

src/main/java/org/json/JSONArray.java

@@ -205,6 +205,22 @@ public JSONArray(Object array) throws JSONException {
         }
     }
 
+    /**
+     * Construct a JSONArray with the specified initial capacity.
+     *
+     * @param initialCapacity
+     *            the initial capacity of the JSONArray.
+     * @throws JSONException
+     *             If the initial capacity is negative.
+     */
+    public JSONArray(int initialCapacity) throws JSONException {
+    	if (initialCapacity < 0) {
+            throw new JSONException(
+                    "JSONArray initial capacity cannot be negative.");
+    	}
+    	this.myArrayList = new ArrayList<Object>(initialCapacity);
+    }
+
     @Override
     public Iterator<Object> iterator() {
         return this.myArrayList.iterator();

src/test/java/org/json/junit/JSONArrayTest.java

@@ -26,6 +26,7 @@ of this software and associated documentation files (the "Software"), to deal
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
@@ -1119,4 +1120,24 @@ public void toList() {
         assertTrue("Removing an entry should succeed", list.remove(2) != null);
         assertTrue("List should have 2 elements", list.size() == 2);
     }
+
+    /**
+     * Create a JSONArray with specified initial capacity.
+     * Expects an exception if the initial capacity is specified as a negative integer 
+     */
+    @Test
+    public void testJSONArrayInt() {
+    	assertNotNull(new JSONArray(0));
+    	assertNotNull(new JSONArray(5));
+    	// Check Size -> Even though the capacity of the JSONArray can be specified using a positive
+    	// integer but the length of JSONArray always reflects upon the items added into it.
+    	assertEquals(0l, (long)new JSONArray(10).length());
+        try {
+        	assertNotNull("Should throw an exception", new JSONArray(-1));
+        } catch (JSONException e) {
+            assertEquals("Expected an exception message", 
+                    "JSONArray initial capacity cannot be negative.",
+                    e.getMessage());
+        }
+    }
 }