--- a/truffle/com.oracle.truffle.object/src/com/oracle/truffle/object/PropertyMap.java	Mon Sep 14 18:07:17 2015 +0200
+++ b/truffle/com.oracle.truffle.object/src/com/oracle/truffle/object/PropertyMap.java	Mon Sep 14 18:32:54 2015 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,332 +26,54 @@
 
 import com.oracle.truffle.api.object.*;
 
-public final class PropertyMap implements Map<Object, Property> {
-    private final PropertyMap car;
-    private final Property cdr;
-    private final int size;
-
-    private static final PropertyMap EMPTY = new PropertyMap();
-
-    private PropertyMap() {
-        this.car = null;
-        this.cdr = null;
-        this.size = 0;
-    }
-
-    private PropertyMap(PropertyMap parent, Property added) {
-        this.car = Objects.requireNonNull(parent);
-        this.cdr = added;
-        this.size = parent.size + 1;
-    }
+/**
+ * Immutable property map.
+ */
+public abstract class PropertyMap implements ImmutableMap<Object, Property> {
 
     public static PropertyMap empty() {
-        return EMPTY;
-    }
-
-    public int size() {
-        return size;
+        return ConsListPropertyMap.empty();
     }
 
-    public boolean isEmpty() {
-        return size() == 0;
-    }
+    public abstract Iterator<Object> orderedKeyIterator();
+
+    public abstract Iterator<Object> reverseOrderedKeyIterator();
 
-    public boolean containsKey(Object key) {
-        for (Map.Entry<Object, Property> entry : reverseOrderEntrySet()) {
-            if (entry.getKey().equals(key)) {
-                return true;
-            }
-        }
-        return false;
-    }
+    public abstract Iterator<Property> orderedValueIterator();
+
+    public abstract Iterator<Property> reverseOrderedValueIterator();
+
+    public abstract Property getLastProperty();
 
-    public boolean containsValue(Object value) {
-        for (Map.Entry<Object, Property> entry : reverseOrderEntrySet()) {
-            if (entry.getValue().equals(value)) {
-                return true;
-            }
-        }
-        return false;
-    }
+    public abstract PropertyMap putCopy(final Property element);
+
+    public abstract PropertyMap replaceCopy(final Property oldValue, final Property newValue);
 
-    public Property get(Object key) {
-        for (Map.Entry<Object, Property> entry : reverseOrderEntrySet()) {
-            if (entry.getKey().equals(key)) {
-                return entry.getValue();
-            }
-        }
-        return null;
-    }
+    public abstract PropertyMap removeCopy(final Property value);
 
-    public Property put(Object key, Property value) {
+    public abstract PropertyMap getParentMap();
+
+    @Override
+    public Property put(final Object key, final Property value) {
         throw unmodifiableException();
     }
 
-    public Property remove(Object key) {
+    @Override
+    public void putAll(final Map<? extends Object, ? extends Property> m) {
         throw unmodifiableException();
     }
 
-    public void putAll(Map<? extends Object, ? extends Property> m) {
+    @Override
+    public Property remove(final Object key) {
         throw unmodifiableException();
     }
 
+    @Override
     public void clear() {
         throw unmodifiableException();
     }
 
-    public Set<Object> keySet() {
-        return new AbstractSet<Object>() {
-            @Override
-            public Iterator<Object> iterator() {
-                Object[] keys = new Object[size()];
-                Iterator<Map.Entry<Object, Property>> iterator = reverseOrderEntrySet().iterator();
-                for (int pos = size() - 1; pos >= 0; pos--) {
-                    keys[pos] = iterator.next().getKey();
-                }
-                return Arrays.asList(keys).iterator();
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    public Collection<Property> values() {
-        return new AbstractSet<Property>() {
-            @Override
-            public Iterator<Property> iterator() {
-                Property[] values = new Property[size()];
-                Iterator<Map.Entry<Object, Property>> iterator = reverseOrderEntrySet().iterator();
-                for (int pos = size() - 1; pos >= 0; pos--) {
-                    values[pos] = iterator.next().getValue();
-                }
-                return Arrays.asList(values).iterator();
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    public Set<Map.Entry<Object, Property>> entrySet() {
-        return new AbstractSet<Map.Entry<Object, Property>>() {
-            @Override
-            public Iterator<Map.Entry<Object, Property>> iterator() {
-                @SuppressWarnings("unchecked")
-                Map.Entry<Object, Property>[] entries = (Map.Entry<Object, Property>[]) new Map.Entry<?, ?>[size()];
-                Iterator<Map.Entry<Object, Property>> iterator = reverseOrderEntrySet().iterator();
-                for (int pos = size() - 1; pos >= 0; pos--) {
-                    entries[pos] = iterator.next();
-                }
-                return Arrays.asList(entries).iterator();
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    public Set<Map.Entry<Object, Property>> reverseOrderEntrySet() {
-        return new AbstractSet<Map.Entry<Object, Property>>() {
-            @Override
-            public Iterator<Map.Entry<Object, Property>> iterator() {
-                return new Iterator<Map.Entry<Object, Property>>() {
-                    PropertyMap current = PropertyMap.this;
-
-                    public Entry<Object, Property> next() {
-                        if (hasNext()) {
-                            try {
-                                return new MapEntryImpl(current.cdr);
-                            } finally {
-                                current = current.car;
-                            }
-                        } else {
-                            throw new NoSuchElementException();
-                        }
-                    }
-
-                    public boolean hasNext() {
-                        return current != empty();
-                    }
-
-                    public void remove() {
-                        throw new UnsupportedOperationException();
-                    }
-                };
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    public Set<Object> reverseOrderKeys() {
-        return new AbstractSet<Object>() {
-            @Override
-            public Iterator<Object> iterator() {
-                return new Iterator<Object>() {
-                    PropertyMap current = PropertyMap.this;
-
-                    public Object next() {
-                        if (hasNext()) {
-                            try {
-                                return current.cdr.getKey();
-                            } finally {
-                                current = current.car;
-                            }
-                        } else {
-                            throw new NoSuchElementException();
-                        }
-                    }
-
-                    public boolean hasNext() {
-                        return current != empty();
-                    }
-
-                    public void remove() {
-                        throw new UnsupportedOperationException();
-                    }
-                };
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    public Set<Property> reverseOrderValues() {
-        return new AbstractSet<Property>() {
-            @Override
-            public Iterator<Property> iterator() {
-                return new Iterator<Property>() {
-                    PropertyMap current = PropertyMap.this;
-
-                    public Property next() {
-                        if (hasNext()) {
-                            try {
-                                return current.cdr;
-                            } finally {
-                                current = current.car;
-                            }
-                        } else {
-                            throw new NoSuchElementException();
-                        }
-                    }
-
-                    public boolean hasNext() {
-                        return current != empty();
-                    }
-
-                    public void remove() {
-                        throw new UnsupportedOperationException();
-                    }
-                };
-            }
-
-            @Override
-            public int size() {
-                return PropertyMap.this.size();
-            }
-        };
-    }
-
-    private static final class MapEntryImpl implements Map.Entry<Object, Property> {
-        private final Property backingProperty;
-
-        public MapEntryImpl(Property backingProperty) {
-            this.backingProperty = backingProperty;
-        }
-
-        public Object getKey() {
-            return backingProperty.getKey();
-        }
-
-        public Property getValue() {
-            return backingProperty;
-        }
-
-        public Property setValue(Property value) {
-            throw unmodifiableException();
-        }
-    }
-
-    private static UnsupportedOperationException unmodifiableException() {
-        throw new UnsupportedOperationException("unmodifiable");
-    }
-
-    public PropertyMap putCopy(Property value) {
-        return new PropertyMap(this, value);
-    }
-
-    public PropertyMap removeCopy(Property value) {
-        Deque<Property> shelve = new ArrayDeque<>();
-        PropertyMap current = this;
-        while (!current.isEmpty()) {
-            if (current.getLastProperty().equals(value)) {
-                PropertyMap newMap = current.getParentMap();
-                for (Property property : shelve) {
-                    newMap = newMap.putCopy(property);
-                }
-                return newMap;
-            } else {
-                shelve.push(current.getLastProperty());
-                current = current.getParentMap();
-            }
-        }
-        return this;
-    }
-
-    public PropertyMap replaceCopy(Property oldValue, Property newValue) {
-        Deque<Property> shelve = new ArrayDeque<>();
-        PropertyMap current = this;
-        while (!current.isEmpty()) {
-            if (current.getLastProperty().equals(oldValue)) {
-                PropertyMap newMap = current.getParentMap();
-                newMap = newMap.putCopy(newValue);
-                for (Property property : shelve) {
-                    newMap = newMap.putCopy(property);
-                }
-                return newMap;
-            } else {
-                shelve.push(current.getLastProperty());
-                current = current.getParentMap();
-            }
-        }
-        return this;
-    }
-
-    public PropertyMap getOwningMap(Property value) {
-        PropertyMap current = this;
-        while (!current.isEmpty()) {
-            if (current.getLastProperty().equals(value)) {
-                return current;
-            }
-            current = current.getParentMap();
-        }
-        return null;
-    }
-
-    PropertyMap getParentMap() {
-        return car;
-    }
-
-    public Property getLastProperty() {
-        return cdr;
-    }
-
-    @Override
-    public String toString() {
-        return values().toString();
+    protected static RuntimeException unmodifiableException() {
+        throw new UnsupportedOperationException();
     }
 }