1 /*
   2  * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.runtime;
  26 
  27 import java.util.*;
  28 import sun.jvm.hotspot.debugger.*;
  29 import sun.jvm.hotspot.types.*;
  30 
  31 /** This class provides generalized "virtual constructor"
  32     functionality for VMObjects. In simple terms, it creates
  33     correctly-typed Java wrapper objects for underlying Addresses,
  34     using the "RTTI-like" functionality of TypeDataBase. For example,
  35     if the given Address really is a DefNewGeneration*, the Java object
  36     created for it will be of type
  37     sun.jvm.hotspot.memory.DefNewGeneration, assuming the mapping from
  38     type "DefNewGeneration" to class
  39     sun.jvm.hotspot.memory.DefNewGeneration has been set up. */
  40 
  41 public class VirtualConstructor extends InstanceConstructor<VMObject> {
  42   private TypeDataBase db;
  43   private Map          map; // Map<String, Class>
  44 
  45   public VirtualConstructor(TypeDataBase db) {
  46     this.db = db;
  47     map     = new HashMap();
  48   }
  49 
  50   /** Adds a mapping from the given C++ type name to the given Java
  51       class. The latter must be a subclass of
  52       sun.jvm.hotspot.runtime.VMObject. Returns false if there was
  53       already a class for this type name in the map. */
  54   public boolean addMapping(String cTypeName, Class clazz) {
  55     if (map.get(cTypeName) != null) {
  56       return false;
  57     }
  58 
  59     map.put(cTypeName, clazz);
  60     return true;
  61   }
  62 
  63   /** Instantiate the most-precisely typed wrapper object available
  64       for the type of the given Address. If no type in the mapping
  65       matched the type of the Address, throws a WrongTypeException.
  66       Returns null for a null address (similar behavior to
  67       VMObjectFactory). */
  68   public VMObject instantiateWrapperFor(Address addr) throws WrongTypeException {
  69     if (addr == null) {
  70       return null;
  71     }
  72 
  73     for (Iterator iter = map.keySet().iterator(); iter.hasNext(); ) {
  74       String typeName = (String) iter.next();
  75       if (db.addressTypeIsEqualToType(addr, db.lookupType(typeName))) {
  76         return (VMObject) VMObjectFactory.newObject((Class) map.get(typeName), addr);
  77       }
  78     }
  79 
  80     throw newWrongTypeException(addr);
  81   }
  82 }