Merge pull request #684 from fredoboulo/fix/682

Problem: Msg.getBytes does not return the bytes of the message.

src/main/java/zmq/Msg.java

@@ -88,7 +88,7 @@ enum Type
     // the file descriptor where this message originated, needs to be 64bit due to alignment
     private SocketChannel fileDesc;
 
-    private int              size;
+    private final int        size;
     private byte[]           data;
     private final ByteBuffer buf;
     // keep track of relative write position
@@ -330,7 +330,7 @@ public int getBytes(int index, byte[] dst, int off, int len)
         if (data == null) {
             ByteBuffer dup = buf.duplicate();
             dup.position(index);
-            dup.put(dst, off, count);
+            dup.get(dst, off, count);
         }
         else {
             System.arraycopy(data, index, dst, off, count);

src/test/java/zmq/TestMsg.java

@@ -1,11 +1,27 @@
 package zmq;
 
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
 import java.nio.ByteBuffer;
+import java.util.function.Function;
 
 import org.junit.Test;
 
 public class TestMsg
 {
+    private final Function<Integer, ByteBuffer> allocator;
+
+    public TestMsg()
+    {
+        this(ByteBuffer::allocateDirect);
+    }
+
+    protected TestMsg(Function<Integer, ByteBuffer> allocator)
+    {
+        this.allocator = allocator;
+    }
+
     @Test(expected = IllegalArgumentException.class)
     public void shouldThrowForNullByteBuffer()
     {
@@ -22,4 +38,61 @@ public void shouldWorkForFlippedBuffers()
         buffer.flip();
         new Msg(buffer);
     }
+
+    @Test
+    public void testGetBytes()
+    {
+        final Msg msg = initMsg();
+
+        final byte[] dst = new byte[3];
+        msg.getBytes(0, dst, 0, 3);
+        assertThat(dst, is(new byte[] { 0, 1, 2 }));
+    }
+
+    @Test
+    public void testGetBytesIndex()
+    {
+        final Msg msg = initMsg();
+
+        final byte[] dst = new byte[4];
+        msg.getBytes(1, dst, 0, 4);
+        assertThat(dst, is(new byte[] { 1, 2, 3, 4 }));
+    }
+
+    @Test
+    public void testGetBytesLength()
+    {
+        final Msg msg = initMsg();
+
+        final byte[] dst = new byte[5];
+        msg.getBytes(2, dst, 0, 2);
+        assertThat(dst, is(new byte[] { 2, 3, 0, 0, 0 }));
+    }
+
+    @Test
+    public void testGetBytesOffset()
+    {
+        final Msg msg = initMsg();
+
+        final byte[] dst = new byte[6];
+        msg.getBytes(3, dst, 1, 2);
+        assertThat(dst, is(new byte[] { 0, 3, 4, 0, 0, 0 }));
+    }
+
+    protected Msg initMsg()
+    {
+        return initDirectMsg(allocator);
+    }
+
+    Msg initDirectMsg(Function<Integer, ByteBuffer> allocator)
+    {
+        int size = 30;
+        final ByteBuffer buffer = allocator.apply(size);
+        for (int idx = 0; idx < size; ++idx) {
+            buffer.put((byte) idx);
+        }
+        buffer.position(0);
+        final Msg msg = new Msg(buffer);
+        return msg;
+    }
 }

src/test/java/zmq/TestMsgDirect.java

@@ -0,0 +1,11 @@
+package zmq;
+
+import java.nio.ByteBuffer;
+
+public class TestMsgDirect extends TestMsg
+{
+    public TestMsgDirect()
+    {
+        super(ByteBuffer::allocate);
+    }
+}