* Grammar fixes

* Implementing optional data members in Java

3 files changed, 102 insertions, 3 deletions

diff --git a/java/src/Ice/Optional.java b/java/src/Ice/Optional.java
new file mode 100644
index 00000000000..87c4b8cb526
--- /dev/null
+++ b/java/src/Ice/Optional.java
@@ -0,0 +1,85 @@
+// **********************************************************************
+//
+// Copyright (c) 2003-2012 ZeroC, Inc. All rights reserved.
+//
+// This copy of Ice is licensed to you under the terms described in the
+// ICE_LICENSE file included in this distribution.
+//
+// **********************************************************************
+
+package Ice;
+
+/**
+ * Generic class for optional parameters.
+ **/
+public class Optional<T>
+{
+    /**
+     * The value defaults to unset.
+     **/
+    public Optional()
+    {
+        _isSet = false;
+    }
+
+    /**
+     * Sets the value to the given argument.
+     *
+     * @param v The initial value.
+     **/
+    public Optional(T v)
+    {
+        _value = v;
+        _isSet = true;
+    }
+
+    /**
+     * Sets the value to a shallow copy of the given optional.
+     *
+     * @param opt The source value.
+     **/
+    public Optional(Optional<T> opt)
+    {
+        _value = opt._value;
+        _isSet = opt._isSet;
+    }
+
+    /**
+     * Obtains the current value.
+     *
+     * @return The current value.
+     * @throws IllegalStateException If the value is not set.
+     **/
+    public T get()
+    {
+        if(!_isSet)
+        {
+            throw new IllegalStateException("no value is set");
+        }
+        return _value;
+    }
+
+    /**
+     * Sets the value to the given argument.
+     *
+     * @param v The new value.
+     **/
+    public void set(T v)
+    {
+        _value = v;
+        _isSet = true;
+    }
+
+    /**
+     * Determines whether the value is set.
+     *
+     * @return True if the value is set, false otherwise.
+     **/
+    public boolean isSet()
+    {
+        return _isSet;
+    }
+
+    private T _value;
+    private boolean _isSet;
+}
diff --git a/java/src/Ice/OutputStream.java b/java/src/Ice/OutputStream.java
index 7d7df18b576..b54fc8a3f92 100644
--- a/java/src/Ice/OutputStream.java
+++ b/java/src/Ice/OutputStream.java
@@ -264,6 +264,14 @@ public interface OutputStream
     void writePendingObjects();
 
     /**
+     * Write the header information for an optional value.
+     *
+     * @param tag The numeric tag associated with the value.
+     * @param type The optional type of the value.
+     **/
+    void writeOptional(int tag, Ice.OptionalType type);
+
+    /**
      * Indicates that marshaling of a request or reply is finished.
      *
      * @return The byte sequence containing the encoded request or reply.
@@ -280,10 +288,10 @@ public interface OutputStream
     /**
      * Inserts a fixed 32-bit size value into the stream at the given position.
      *
+     * @param sz The 32-bit size value.
      * @param pos The position at which to write the value.
-     * @param sz The size value.
      **/
-    void rewrite(int pos, int sz);
+    void rewrite(int sz, int pos);
 
     /**
      * Resets this output stream. This method allows the stream to be reused, to avoid creating
diff --git a/java/src/Ice/OutputStreamI.java b/java/src/Ice/OutputStreamI.java
index d7b4ffd23d5..60973c2fc69 100644
--- a/java/src/Ice/OutputStreamI.java
+++ b/java/src/Ice/OutputStreamI.java
@@ -243,6 +243,12 @@ public class OutputStreamI implements OutputStream
         _os.writePendingObjects();
     }
 
+    public void
+    writeOptional(int tag, Ice.OptionalType type)
+    {
+        _os.writeOpt(tag, type);
+    }
+
     public byte[]
     finished()
     {
@@ -260,7 +266,7 @@ public class OutputStreamI implements OutputStream
     }
 
     public void
-    rewrite(int pos, int sz)
+    rewrite(int sz, int pos)
     {
         _os.writeInt(sz, pos);
     }