Variant.java

/*
   D-Bus Java Implementation
   Copyright (c) 2005-2006 Matthew Johnson

   This program is free software; you can redistribute it and/or modify it
   under the terms of either the GNU Lesser General Public License Version 2 or the
   Academic Free Licence Version 2.1.

   Full licence texts are included in the COPYING file with this program.
*/
package org.freedesktop.dbus;

import static org.freedesktop.dbus.Gettext._;

import java.lang.reflect.Type;
import java.text.MessageFormat;
import java.util.Vector;
import org.freedesktop.dbus.exceptions.DBusException;

import cx.ath.matthew.debug.Debug;

/**
 * A Wrapper class for Variant values. 
 * A method on DBus can send or receive a Variant. 
 * This will wrap another value whose type is determined at runtime.
 * The Variant may be parameterized to restrict the types it may accept.
 */
public class Variant<T>
{
   private final T o;
   private final Type type;
   private final String sig;
   /** 
    * Create a Variant from a basic type object.
    * @param o The wrapped value.
    * @throws IllegalArugmentException If you try and wrap Null or an object of a non-basic type.
    */
   public Variant(T o) throws IllegalArgumentException
   {
      if (null == o) throw new IllegalArgumentException(_("Can't wrap Null in a Variant"));
      type = o.getClass();
      try {
         String[] ss = Marshalling.getDBusType(o.getClass(), true);
         if (ss.length != 1)
         throw new IllegalArgumentException(_("Can't wrap a multi-valued type in a Variant: ")+type);
         this.sig = ss[0];
      } catch (DBusException DBe) {
         if (AbstractConnection.EXCEPTION_DEBUG && Debug.debug) Debug.print(Debug.ERR, DBe);
         throw new IllegalArgumentException(MessageFormat.format(_("Can't wrap {0} in an unqualified Variant ({1})."), new Object[] { o.getClass(), DBe.getMessage() }));
      }
      this.o = o;
   }
   /** 
    * Create a Variant.
    * @param o The wrapped value.
    * @param type The explicit type of the value.
    * @throws IllegalArugmentException If you try and wrap Null or an object which cannot be sent over DBus.
    */
   public Variant(T o, Type type) throws IllegalArgumentException
   {
      if (null == o) throw new IllegalArgumentException(_("Can't wrap Null in a Variant"));
      this.type = type;
      try {
         String[] ss = Marshalling.getDBusType(type);
         if (ss.length != 1)
         throw new IllegalArgumentException(_("Can't wrap a multi-valued type in a Variant: ")+type);
         this.sig = ss[0];
      } catch (DBusException DBe) {
         if (AbstractConnection.EXCEPTION_DEBUG && Debug.debug) Debug.print(Debug.ERR, DBe);
         throw new IllegalArgumentException(MessageFormat.format(_("Can't wrap {0} in an unqualified Variant ({1})."), new Object[] { type, DBe.getMessage() }));
      }
      this.o = o;
   }
   /** 
    * Create a Variant.
    * @param o The wrapped value.
    * @param sig The explicit type of the value, as a dbus type string.
    * @throws IllegalArugmentException If you try and wrap Null or an object which cannot be sent over DBus.
    */
   public Variant(T o, String sig) throws IllegalArgumentException
   {
      if (null == o) throw new IllegalArgumentException(_("Can't wrap Null in a Variant"));
      this.sig = sig;
      try {
         Vector<Type> ts = new Vector<Type>();
         Marshalling.getJavaType(sig, ts,1);
         if (ts.size() != 1)
            throw new IllegalArgumentException(_("Can't wrap multiple or no types in a Variant: ")+sig);
         this.type = ts.get(0);
      } catch (DBusException DBe) {
         if (AbstractConnection.EXCEPTION_DEBUG && Debug.debug) Debug.print(Debug.ERR, DBe);
         throw new IllegalArgumentException(MessageFormat.format(_("Can't wrap {0} in an unqualified Variant ({1})."), new Object[] { sig, DBe.getMessage() }));
      }
      this.o = o;
   }
   /** Return the wrapped value. */
   public T getValue() { return o; }
   /** Return the type of the wrapped value. */
   public Type getType() { return type; }
   /** Return the dbus signature of the wrapped value. */
   public String getSig() { return sig; }
   /** Format the Variant as a string. */
   public String toString() { return "["+o+"]"; }
   /** Compare this Variant with another by comparing contents */
   @SuppressWarnings("unchecked")
   public boolean equals(Object other)
   {
      if (null == other) return false;
      if (!(other instanceof Variant)) return false;
      return this.o.equals(((Variant<? extends Object>)other).o);
   }
}