Extracted the utility methods in ZlibEncoder to a new utility class 'ZlibUtil'

src/main/java/org/jboss/netty/handler/codec/compression/ZlibDecoder.java

@@ -48,7 +48,7 @@ public class ZlibDecoder extends OneToOneDecoder {
     public ZlibDecoder() throws ZStreamException {
         int resultCode = z.inflateInit();
         if (resultCode != JZlib.Z_OK) {
-            ZlibEncoder.fail(z, "initialization failure", resultCode);
+            ZlibUtil.fail(z, "initialization failure", resultCode);
         }
     }
 
@@ -65,11 +65,11 @@ public class ZlibDecoder extends OneToOneDecoder {
         int resultCode;
         resultCode = z.inflateInit();
         if (resultCode != JZlib.Z_OK) {
-            ZlibEncoder.fail(z, "initialization failure", resultCode);
+            ZlibUtil.fail(z, "initialization failure", resultCode);
         } else {
             resultCode = z.inflateSetDictionary(dictionary, dictionary.length);
             if (resultCode != JZlib.Z_OK) {
-                ZlibEncoder.fail(z, "failed to set the dictionary", resultCode);
+                ZlibUtil.fail(z, "failed to set the dictionary", resultCode);
             }
         }
     }
@@ -111,9 +111,7 @@ public class ZlibDecoder extends OneToOneDecoder {
                     z.avail_out = out.length;
                     break;
                 default:
-                    throw new ZStreamException(
+                    ZlibUtil.fail(z, "decompression failure", resultCode);
-                            "decompression failure (" + resultCode + ")" +
-                            (z.msg != null? ": " + z.msg : ""));
                 }
             } while (z.avail_in > 0);
 

src/main/java/org/jboss/netty/handler/codec/compression/ZlibEncoder.java

@@ -79,7 +79,7 @@ public class ZlibEncoder extends OneToOneEncoder {
     public ZlibEncoder(int compressionLevel) throws ZStreamException {
         int resultCode = z.deflateInit(compressionLevel, false); // Default: ZLIB format
         if (resultCode != JZlib.Z_OK) {
-            fail(z, "initialization failure", resultCode);
+            ZlibUtil.fail(z, "initialization failure", resultCode);
         }
     }
 
@@ -119,11 +119,11 @@ public class ZlibEncoder extends OneToOneEncoder {
         int resultCode;
         resultCode = z.deflateInit(compressionLevel, false); // Default: ZLIB format
         if (resultCode != JZlib.Z_OK) {
-            fail(z, "initialization failure", resultCode);
+            ZlibUtil.fail(z, "initialization failure", resultCode);
         } else {
             resultCode = z.deflateSetDictionary(dictionary, dictionary.length);
             if (resultCode != JZlib.Z_OK){
-                fail(z, "failed to set the dictionary", resultCode);
+                ZlibUtil.fail(z, "failed to set the dictionary", resultCode);
             }
         }
     }
@@ -152,7 +152,7 @@ public class ZlibEncoder extends OneToOneEncoder {
             // Note that Z_PARTIAL_FLUSH has been deprecated.
             int resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
             if (resultCode != JZlib.Z_OK) {
-                fail(z, "compression failure", resultCode);
+                ZlibUtil.fail(z, "compression failure", resultCode);
             }
 
             if (z.next_out_index != 0) {
@@ -216,7 +216,7 @@ public class ZlibEncoder extends OneToOneEncoder {
             if (resultCode != JZlib.Z_OK && resultCode != JZlib.Z_STREAM_END) {
                 future = Channels.failedFuture(
                         ctx.getChannel(),
-                        exception(z, "compression failure", resultCode));
+                        ZlibUtil.exception(z, "compression failure", resultCode));
             } else if (z.next_out_index != 0) {
                 future = Channels.future(ctx.getChannel());
                 Channels.write(
@@ -250,13 +250,4 @@ public class ZlibEncoder extends OneToOneEncoder {
             z.next_out = null;
         }
     }
-
-    static void fail(ZStream z, String message, int resultCode) throws ZStreamException {
-        throw exception(z, message, resultCode);
-    }
-
-    static ZStreamException exception(ZStream z, String message, int resultCode) {
-        return new ZStreamException(message + " (" + resultCode + ")" +
-                (z.msg != null? ": " + z.msg : ""));
-    }
 }

src/main/java/org/jboss/netty/handler/codec/compression/ZlibUtil.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat licenses this file to you under the Apache License, version 2.0
+ * (the "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at:
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package org.jboss.netty.handler.codec.compression;
+
+import com.jcraft.jzlib.ZStream;
+import com.jcraft.jzlib.ZStreamException;
+
+/**
+ * Utility methods used by {@link ZlibEncoder} and {@link ZlibDecoder}.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ * @version $Rev$, $Date$
+ */
+class ZlibUtil {
+
+    static void fail(ZStream z, String message, int resultCode) throws ZStreamException {
+        throw exception(z, message, resultCode);
+    }
+
+    static ZStreamException exception(ZStream z, String message, int resultCode) {
+        return new ZStreamException(message + " (" + resultCode + ")" +
+                (z.msg != null? ": " + z.msg : ""));
+    }
+
+    private ZlibUtil() {
+        super();
+    }
+}