1 files changed, 145 insertions, 0 deletions

diff --git a/server/src/com/vaadin/util/SerializerHelper.java b/server/src/com/vaadin/util/SerializerHelper.java
new file mode 100644
index 0000000000..5b7b388dd6
--- /dev/null
+++ b/server/src/com/vaadin/util/SerializerHelper.java
@@ -0,0 +1,145 @@
+/*
+@VaadinApache2LicenseForJavaFiles@
+ */
+package com.vaadin.util;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+/**
+ * Helper class for performing serialization. Most of the methods are here are
+ * workarounds for problems in Google App Engine. Used internally by Vaadin and
+ * should not be used by application developers. Subject to change at any time.
+ * 
+ * @since 6.0
+ */
+public class SerializerHelper {
+
+    /**
+     * Serializes the class reference so {@link #readClass(ObjectInputStream)}
+     * can deserialize it. Supports null class references.
+     * 
+     * @param out
+     *            The {@link ObjectOutputStream} to serialize to.
+     * @param cls
+     *            A class or null.
+     * @throws IOException
+     *             Rethrows any IOExceptions from the ObjectOutputStream
+     */
+    public static void writeClass(ObjectOutputStream out, Class<?> cls)
+            throws IOException {
+        if (cls == null) {
+            out.writeObject(null);
+        } else {
+            out.writeObject(cls.getName());
+        }
+
+    }
+
+    /**
+     * Serializes the class references so
+     * {@link #readClassArray(ObjectInputStream)} can deserialize it. Supports
+     * null class arrays.
+     * 
+     * @param out
+     *            The {@link ObjectOutputStream} to serialize to.
+     * @param classes
+     *            An array containing class references or null.
+     * @throws IOException
+     *             Rethrows any IOExceptions from the ObjectOutputStream
+     */
+    public static void writeClassArray(ObjectOutputStream out,
+            Class<?>[] classes) throws IOException {
+        if (classes == null) {
+            out.writeObject(null);
+        } else {
+            String[] classNames = new String[classes.length];
+            for (int i = 0; i < classes.length; i++) {
+                classNames[i] = classes[i].getName();
+            }
+            out.writeObject(classNames);
+        }
+    }
+
+    /**
+     * Deserializes a class references serialized by
+     * {@link #writeClassArray(ObjectOutputStream, Class[])}. Supports null
+     * class arrays.
+     * 
+     * @param in
+     *            {@link ObjectInputStream} to read from.
+     * @return Class array with the class references or null.
+     * @throws ClassNotFoundException
+     *             If one of the classes could not be resolved.
+     * @throws IOException
+     *             Rethrows IOExceptions from the ObjectInputStream
+     */
+    public static Class<?>[] readClassArray(ObjectInputStream in)
+            throws ClassNotFoundException, IOException {
+        String[] classNames = (String[]) in.readObject();
+        if (classNames == null) {
+            return null;
+        }
+        Class<?>[] classes = new Class<?>[classNames.length];
+        for (int i = 0; i < classNames.length; i++) {
+            classes[i] = resolveClass(classNames[i]);
+        }
+
+        return classes;
+    }
+
+    /**
+     * List of primitive classes. Google App Engine has problems
+     * serializing/deserializing these (#3064).
+     */
+    private static Class<?>[] primitiveClasses = new Class<?>[] { byte.class,
+            short.class, int.class, long.class, float.class, double.class,
+            boolean.class, char.class };
+
+    /**
+     * Resolves the class given by {@code className}.
+     * 
+     * @param className
+     *            The fully qualified class name.
+     * @return A {@code Class} reference.
+     * @throws ClassNotFoundException
+     *             If the class could not be resolved.
+     */
+    public static Class<?> resolveClass(String className)
+            throws ClassNotFoundException {
+        for (Class<?> c : primitiveClasses) {
+            if (className.equals(c.getName())) {
+                return c;
+            }
+        }
+
+        return Class.forName(className);
+    }
+
+    /**
+     * Deserializes a class reference serialized by
+     * {@link #writeClass(ObjectOutputStream, Class)}. Supports null class
+     * references.
+     * 
+     * @param in
+     *            {@code ObjectInputStream} to read from.
+     * @return Class reference to the resolved class
+     * @throws ClassNotFoundException
+     *             If the class could not be resolved.
+     * @throws IOException
+     *             Rethrows IOExceptions from the ObjectInputStream
+     */
+    public static Class<?> readClass(ObjectInputStream in) throws IOException,
+            ClassNotFoundException {
+        String className = (String) in.readObject();
+        if (className == null) {
+            return null;
+        } else {
+            return resolveClass(className);
+
+        }
+
+    }
+
+}