introduced custom field serializers for com.sap.sse.common types in com.sap.sse.gwt;

This avoids a direct dependency of com.sap.sse.common on GWT code. The custom field serializers are
bundled in a new module "SSECommonSerializers" which is inherited by the SSESharedGWT module and hence
exposed to all modules inheriting SSESharedGWT.

Further classes in com.sap.sailing.domain.common could have final fields and no no-arg constructor.
Started with ImageSizeImpl. The corresponding custom field serializers can go to com.sap.sailing.gwt.ui
which is the GWT-dependent module using the com.sap.sailing.domain.common stuff.

java/com.sap.sse.gwt/src/com/sap/sse/common/SSECommonSerializers.gwt.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.7.0//EN" "http://gwtproject.org/doctype/2.7.0/gwt-module.dtd">
+<module>
+  <source path='impl'/>
+</module>

java/com.sap.sse.gwt/src/com/sap/sse/common/impl/HSVColor_CustomFieldSerializer.java

@@ -0,0 +1,52 @@
+package com.sap.sse.common.impl;
+
+import com.google.gwt.user.client.rpc.CustomFieldSerializer;
+import com.google.gwt.user.client.rpc.SerializationException;
+import com.google.gwt.user.client.rpc.SerializationStreamReader;
+import com.google.gwt.user.client.rpc.SerializationStreamWriter;
+import com.sap.sse.common.impl.HSVColor;
+
+public class HSVColor_CustomFieldSerializer extends CustomFieldSerializer<HSVColor> {
+    public static void serialize(SerializationStreamWriter streamWriter, HSVColor instance) throws SerializationException {
+        streamWriter.writeFloat(instance.getHue());
+        streamWriter.writeFloat(instance.getSaturation());
+        streamWriter.writeFloat(instance.getBrightness());
+    }
+    
+    public static HSVColor instantiate(SerializationStreamReader streamReader) throws SerializationException {
+        final float hue = streamReader.readFloat();
+        final float saturation = streamReader.readFloat();
+        final float brightness = streamReader.readFloat();
+        return new HSVColor(hue, saturation, brightness);
+    }
+    
+    public static boolean hasCustomInstantiate() {
+        return true;
+    }
+    
+    public static void deserialize(SerializationStreamReader streamReader, HSVColor instance)
+            throws SerializationException {
+        // no operation
+    }
+    
+    @Override
+    public void serializeInstance(SerializationStreamWriter streamWriter, HSVColor instance) throws SerializationException {
+        serialize(streamWriter, instance);
+    }
+    
+    @Override
+    public HSVColor instantiateInstance(SerializationStreamReader streamReader) throws SerializationException {
+        return instantiate(streamReader);
+    }
+    
+    @Override
+    public boolean hasCustomInstantiateInstance() {
+        return hasCustomInstantiate();
+    }
+    
+    @Override
+    public void deserializeInstance(SerializationStreamReader streamReader, HSVColor instance)
+            throws SerializationException {
+        deserialize(streamReader, instance);
+    }
+}

java/com.sap.sse.gwt/src/com/sap/sse/common/impl/RGBColor_CustomFieldSerializer.java

@@ -0,0 +1,52 @@
+package com.sap.sse.common.impl;
+
+import com.google.gwt.user.client.rpc.CustomFieldSerializer;
+import com.google.gwt.user.client.rpc.SerializationException;
+import com.google.gwt.user.client.rpc.SerializationStreamReader;
+import com.google.gwt.user.client.rpc.SerializationStreamWriter;
+import com.sap.sse.common.impl.RGBColor;
+
+public class RGBColor_CustomFieldSerializer extends CustomFieldSerializer<RGBColor> {
+    public static void serialize(SerializationStreamWriter streamWriter, RGBColor instance) throws SerializationException {
+        streamWriter.writeInt(instance.getRed());
+        streamWriter.writeInt(instance.getGreen());
+        streamWriter.writeInt(instance.getBlue());
+    }
+    
+    public static RGBColor instantiate(SerializationStreamReader streamReader) throws SerializationException {
+        final int red = streamReader.readInt();
+        final int green = streamReader.readInt();
+        final int blue = streamReader.readInt();
+        return new RGBColor(red, green, blue);
+    }
+    
+    public static boolean hasCustomInstantiate() {
+        return true;
+    }
+    
+    public static void deserialize(SerializationStreamReader streamReader, RGBColor instance)
+            throws SerializationException {
+        // no operation
+    }
+    
+    @Override
+    public void serializeInstance(SerializationStreamWriter streamWriter, RGBColor instance) throws SerializationException {
+        serialize(streamWriter, instance);
+    }
+    
+    @Override
+    public RGBColor instantiateInstance(SerializationStreamReader streamReader) throws SerializationException {
+        return instantiate(streamReader);
+    }
+    
+    @Override
+    public boolean hasCustomInstantiateInstance() {
+        return hasCustomInstantiate();
+    }
+    
+    @Override
+    public void deserializeInstance(SerializationStreamReader streamReader, RGBColor instance)
+            throws SerializationException {
+        deserialize(streamReader, instance);
+    }
+}

java/com.sap.sse.gwt/src/com/sap/sse/gwt/SSESharedGWT.gwt.xml

@@ -2,6 +2,7 @@
 <!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.7.0//EN" "http://gwtproject.org/doctype/2.7.0/gwt-module.dtd">
 <module>
   <inherits name="com.google.gwt.activity.Activity" />
+  <inherits name="com.sap.sse.common.SSECommonSerializers" />
   <source path='client'/>
   <source path='shared'/>
 </module>