msgpack · xerial · Jun 4, 2014 · May 20, 2014 · May 20, 2014 · May 20, 2014
diff --git a/README.md b/README.md
@@ -0,0 +1,73 @@
+MessagePack for Java
+=== 
+
+[MessagePack](http://msgpack.org) is an efficient binary serialization format. It lets you exchange data among multiple languages like JSON. But it's faster and smaller. Small integers are encoded into a single byte, and typical short strings require only one extra byte in addition to the strings themselves.
+
+ * Message Pack specification: <https://github.com/msgpack/msgpack/blob/master/spec.md>
+
+## Quick Start
+
+For Maven users:
+```
+<dependency>
+   <groupId>org.msgpack</groupId>
+   <artifactId>msgpack-core</artifactId>
+   <version>0.7.0</version>
+</dependency>
+```
+
+For sbt users:
+```
+libraryDependencies += "org.msgpack" % "msgpack-core" % "0.7.0"
+```
+
+
+## For Developers
+
+msgpack-java uses [sbt](http://www.scala-sbt.org/) for building the projects. For the basic usage of sbt, see:
+ * [Building Java projects with sbt](http://xerial.org/blog/2014/03/24/sbt/)
+
+### Basic sbt commands
+Enter the sbt console:
+```
+$ ./sbt
+```
+
+Here is a list of sbt commands for daily development:
+```
+> ~compile                                 # Compile source codes
+> ~test:compile                            # Compile both source and test codes
+> ~test                                    # Run tests upon source code change
+> ~test-only *MessagePackTest              # Run tests in the specified class
+> ~test-only *MessagePackTest -- -n prim   # Run the test tagged as "prim"
+> project msgpack-core                     # Focus on a specific project
+> package                                  # Create a jar file in the target folder of each project
+> findbugs                                 # Produce findbugs report in target/findbugs
+> jacoco:cover                             # Report the code coverage of tests to target/jacoco folder
+```
+
+### Publishing
+
+```
+> publishLocal            # Install to local .ivy2 repository
+> publishM2               # Install to local .m2 Maven repository
+> publishSigned           # Publish GPG signed artifacts to the Sonatype repository
+> sonatypeRelease         # Publish to the Maven Central (It will be synched within less than 4 hours)
+```
+
+For publishing to Maven central, msgpack-java uses [sbt-sonatype](https://github.com/xerial/sbt-sonatype) plugin. Set Sonatype account information (user name and password) in the global sbt settings. To protect your password, never include this file in your project.
+
+___$HOME/.sbt/(sbt-version)/sonatype.sbt___
+
+```
+credentials += Credentials("Sonatype Nexus Repository Manager",
+        "oss.sonatype.org",
+        "(Sonatype user name)",
+        "(Sonatype password)")
+```
+
+### Project Structure
+
+```
+msgpack-core                 # Contains packer/unpacker implementation that never uses third-party libraries
+```
diff --git a/develop.md b/develop.md
diff --git a/msgpack-core/src/main/java/org/msgpack/core/ExtendedTypeHeader.java b/msgpack-core/src/main/java/org/msgpack/core/ExtendedTypeHeader.java
@@ -1,14 +1,18 @@
 package org.msgpack.core;
 
+import static org.msgpack.core.Preconditions.*;
+
 /**
- * Header of extended type
+ * Header of the extended types
  */
 public class ExtendedTypeHeader {
-    private final int type;
     private final int length;
-    ExtendedTypeHeader(int type, int length) {
-        this.type = type;
+    private final int type;
+
+    ExtendedTypeHeader(int length, int type) {
+        checkArgument(length >= 0, String.format("length must be >= 0: %,d", length));
         this.length = length;
+        this.type = type;
     }
 
     public int getType() {
@@ -18,4 +22,24 @@ public int getType() {
     public int getLength() {
         return length;
     }
+
+    @Override
+    public int hashCode() {
+        return (type + 31) * 31 + length;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if(obj instanceof ExtendedTypeHeader) {
+            ExtendedTypeHeader other = (ExtendedTypeHeader) obj;
+            return this.type == other.type && this.length == other.length;
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("ExtendedTypeHeader(type:%d, length:%,d)", type, length);
+    }
+
 }