Resolved issue: NETTY-254 Do not do lazy-initialization in dynamic buffer

* No lazy initialization anymore for DynamicChannelBuffer - it just causes confusion to users!

src/main/java/org/jboss/netty/buffer/DynamicChannelBuffer.java

@@ -38,9 +38,8 @@ import java.nio.channels.ScatteringByteChannel;
 public class DynamicChannelBuffer extends AbstractChannelBuffer {
 
     private final ChannelBufferFactory factory;
-    private final int initialCapacity;
     private final ByteOrder endianness;
-    private ChannelBuffer buffer = ChannelBuffers.EMPTY_BUFFER;
+    private ChannelBuffer buffer;
 
     public DynamicChannelBuffer(int estimatedLength) {
         this(ByteOrder.BIG_ENDIAN, estimatedLength);
@@ -61,8 +60,8 @@ public class DynamicChannelBuffer extends AbstractChannelBuffer {
             throw new NullPointerException("factory");
         }
         this.factory = factory;
-        initialCapacity = estimatedLength;
         this.endianness = endianness;
+        buffer = factory.getBuffer(order(), estimatedLength);
     }
 
     public ChannelBufferFactory factory() {
@@ -268,10 +267,7 @@ public class DynamicChannelBuffer extends AbstractChannelBuffer {
 
         int newCapacity;
         if (capacity() == 0) {
-            newCapacity = initialCapacity;
-            if (newCapacity == 0) {
             newCapacity = 1;
-            }
         } else {
             newCapacity = capacity();
         }

src/test/java/org/jboss/netty/buffer/DynamicChannelBufferTest.java

@@ -17,6 +17,8 @@ package org.jboss.netty.buffer;
 
 import static org.junit.Assert.*;
 
+import java.nio.ByteOrder;
+
 import org.junit.Test;
 
 /**
@@ -34,14 +36,7 @@ public class DynamicChannelBufferTest extends AbstractChannelBufferTest {
     protected ChannelBuffer newBuffer(int length) {
         buffer = ChannelBuffers.dynamicBuffer(length);
 
-        // A dynamic buffer does lazy initialization.
-        assertEquals(0, buffer.capacity());
-
-        // Initialize.
-        buffer.writeZero(1);
-        buffer.clear();
-
-        // And validate the initial capacity
+        assertEquals(0, buffer.readerIndex());
         assertEquals(0, buffer.writerIndex());
         assertEquals(length, buffer.capacity());
 
@@ -57,4 +52,21 @@ public class DynamicChannelBufferTest extends AbstractChannelBufferTest {
     public void shouldNotAllowNullInConstructor() {
         new DynamicChannelBuffer(null, 0);
     }
+
+    @Test
+    public void shouldNotFailOnInitialIndexUpdate() {
+        new DynamicChannelBuffer(ByteOrder.BIG_ENDIAN, 10).setIndex(0, 10);
+    }
+
+    @Test
+    public void shouldNotFailOnInitialIndexUpdate2() {
+        new DynamicChannelBuffer(ByteOrder.BIG_ENDIAN, 10).writerIndex(10);
+    }
+
+    @Test
+    public void shouldNotFailOnInitialIndexUpdate3() {
+        ChannelBuffer buf = new DynamicChannelBuffer(ByteOrder.BIG_ENDIAN, 10);
+        buf.writerIndex(10);
+        buf.readerIndex(10);
+    }
 }