Ability to disable array content printout on UnsafeBuffer#toString().

agrona/src/main/java/org/agrona/ExpandableArrayBuffer.java

@@ -38,6 +38,10 @@
  */
 public class ExpandableArrayBuffer implements MutableDirectBuffer
 {
+
+    private static final boolean SHOULD_PRINT_ARRAY_CONTENT =
+        !Boolean.getBoolean(DISABLE_ARRAY_CONTENT_PRINTOUT_PROP_NAME);
+
     /**
      * Maximum length to which the underlying buffer can grow. Some JVMs set bits in the last few bytes.
      */
@@ -1107,7 +1111,7 @@ public int compareTo(final DirectBuffer that)
     public String toString()
     {
         return "ExpandableArrayBuffer{" +
-            "byteArray=" + Arrays.toString(byteArray) +
+            "byteArray=" + (SHOULD_PRINT_ARRAY_CONTENT ? Arrays.toString(byteArray) : byteArray) +
             '}';
     }
 }

agrona/src/main/java/org/agrona/MutableDirectBuffer.java

@@ -26,6 +26,12 @@
  */
 public interface MutableDirectBuffer extends DirectBuffer
 {
+
+    /**
+     * Don't print the content of the array while calling toString() on buffer instance.
+     */
+    String DISABLE_ARRAY_CONTENT_PRINTOUT_PROP_NAME = "agrona.disable.array.printout";
+
     /**
      * Is this buffer expandable to accommodate putting data into it beyond the current capacity?
      *

agrona/src/main/java/org/agrona/concurrent/UnsafeBuffer.java

@@ -55,6 +55,8 @@ public class UnsafeBuffer implements AtomicBuffer
 
     public static final String DISABLE_BOUNDS_CHECKS_PROP_NAME = "agrona.disable.bounds.checks";
     public static final boolean SHOULD_BOUNDS_CHECK = !Boolean.getBoolean(DISABLE_BOUNDS_CHECKS_PROP_NAME);
+    public static final boolean SHOULD_PRINT_ARRAY_CONTENT =
+        !Boolean.getBoolean(DISABLE_ARRAY_CONTENT_PRINTOUT_PROP_NAME);
 
     private long addressOffset;
     private int capacity;
@@ -1752,7 +1754,8 @@ public String toString()
         return "UnsafeBuffer{" +
             "addressOffset=" + addressOffset +
             ", capacity=" + capacity +
-            ", byteArray=" + Arrays.toString(byteArray) +
+            ", byteArray=" + (SHOULD_PRINT_ARRAY_CONTENT ?
+                Arrays.toString(byteArray) : byteArray) +
             ", byteBuffer=" + byteBuffer +
             '}';
     }

agrona/src/test/java/org/agrona/concurrent/UnsafeBufferTest.java

@@ -22,6 +22,8 @@
 import org.junit.experimental.theories.Theory;
 import org.junit.runner.RunWith;
 
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
@@ -30,8 +32,7 @@
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.lessThan;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
+import static org.junit.Assert.*;
 
 @RunWith(Theories.class)
 public class UnsafeBufferTest
@@ -236,6 +237,25 @@ private void putAscii(final UnsafeBuffer buffer, final String value)
         buffer.putBytes(INDEX, value.getBytes(US_ASCII));
     }
 
+    @Test
+    public void shouldSkipArrayContentPrintout() throws Exception
+    {
+        final Field settingField = UnsafeBuffer.class.getDeclaredField("SHOULD_PRINT_ARRAY_CONTENT");
+        settingField.setAccessible(true);
+        final Field modifiersField = Field.class.getDeclaredField("modifiers");
+        modifiersField.setAccessible(true);
+        modifiersField.setInt(settingField, settingField.getModifiers() & ~Modifier.FINAL);
+
+        final byte[] backingArray = new byte[10];
+        final UnsafeBuffer unsafeBuffer = new UnsafeBuffer(backingArray);
+
+        settingField.set(null, true);
+        assertTrue(unsafeBuffer.toString().contains(Arrays.toString(backingArray)));
+
+        settingField.set(null, false);
+        assertFalse(unsafeBuffer.toString().contains(Arrays.toString(backingArray)));
+    }
+
     @DataPoints
     public static int[][] valuesAndLengths()
     {