javaunohelper/com/sun/star/lib/uno/helper/WeakBase.java

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  30
  31 package com.sun.star.lib.uno.helper;
  32 import com.sun.star.uno.XWeak;
  33 import com.sun.star.uno.XAdapter;
  34 import com.sun.star.lang.XTypeProvider;
  35 import com.sun.star.uno.Type;
  36 import java.util.Vector;
  37 import java.util.Map;
  38 import java.util.Hashtable;
  39
  40
  41 /** This class can be used as the base class for UNO components. It implements the capability
  42  *  to be kept weak (com.sun.star.uno.XWeak) and it implements com.sun.star.lang.XTypeProvider
  43  *  which is necessary for using the component with StarBasic.
  44  */
  45 public class WeakBase implements XWeak, XTypeProvider
  46 {
  47     private final boolean DEBUG= false;
  48
  49     // Contains all WeakAdapter which have been created in this class
  50     // They have to be notified when this object dies
  51     private WeakAdapter m_adapter;
  52
  53     protected static Map _mapImplementationIds= new Hashtable();
  54     protected static Map _mapTypes= new Hashtable();
  55
  56     /** Method of XWeak. The returned XAdapter implementation can be used to keap
  57      * a weak reference to this object.
  58      * @return a com.sun.star.uno.XAdapter implementation.
  59      */
  60     synchronized public XAdapter queryAdapter()
  61     {
  62         if (m_adapter == null)
  63             m_adapter= new WeakAdapter(this);
  64         return m_adapter;
  65     }
  66
  67     /** Override of Object.finalize. When there are no references to this object anymore
  68      * then the garbage collector calls this method. Thereby causing the adapter object
  69      * to be notified. The adapter, in turn, notifies all listeners (com.sun.star.uno.XReference)
  70      */
  71     protected void finalize() throws java.lang.Throwable
  72     {
  73         if (m_adapter != null)
  74             m_adapter.referentDying();
  75         super.finalize();
  76     }
  77
  78     /** Method of XTypeProvider. It returns an array of Type objects which represent
  79      * all implemented UNO interfaces of this object.
  80      * @return Type objects of all implemented interfaces.
  81      */
  82     public Type[] getTypes()
  83     {
  84         Type[] arTypes= (Type[]) _mapTypes.get( getClass());
  85         if (arTypes == null)
  86         {
  87             Vector vec= new Vector();
  88             Class currentClass= getClass();
  89             do
  90             {
  91                 Class interfaces[]= currentClass.getInterfaces();
  92                 for(int i = 0; i < interfaces.length; ++ i)
  93                 {
  94                     // Test if it is a UNO interface
  95                     if (com.sun.star.uno.XInterface.class.isAssignableFrom((interfaces[i])))
  96                         vec.add(new Type(interfaces[i]));
  97                 }
  98                 // get the superclass the currentClass inherits from
  99                 currentClass= currentClass.getSuperclass();
 100             } while (currentClass != null);
 101
 102             Type types[]= new Type[vec.size()];
 103             for( int i= 0; i < types.length; i++)
 104                 types[i]= (Type) vec.elementAt(i);
 105             _mapTypes.put(getClass(), types);
 106             arTypes= types;
 107         }
 108         return arTypes;
 109     }
 110
 111     /** Method of XTypeProvider. It provides an identifier that represents the set of UNO
 112      * interfaces implemented by this class. All instances of this class
 113      * which run in the same Java Virtual Machine return the same array. (This only works as long
 114      * the ClassLoader preserves the class even if no instance exist.)
 115      *@return identifier as array of bytes
 116      */
 117     public byte[] getImplementationId()
 118     {
 119         byte[] id= null;
 120         synchronized (_mapImplementationIds)
 121         {
 122             id= (byte[]) _mapImplementationIds.get(getClass());
 123
 124             if (id == null)
 125             {
 126                 int hash = hashCode();
 127                 String sName= getClass().getName();
 128                 byte[] arName= sName.getBytes();
 129                 int nNameLength= arName.length;
 130
 131                 id= new byte[ 4 + nNameLength];
 132                 id[0]= (byte)(hash & 0xff);
 133                 id[1]= (byte)((hash >>> 8) & 0xff);
 134                 id[2]= (byte)((hash >>> 16) & 0xff);
 135                 id[3]= (byte)((hash >>>24) & 0xff);
 136
 137                 for (int i= 0; i < nNameLength; i++)
 138                 {
 139                     id[4 + i]= arName[i];
 140                 }
 141                 _mapImplementationIds.put(getClass(), id);
 142             }
 143         }
 144         return id;
 145     }
 146 }