Merge pull request #71 from jentfoo/issue70

Fix ClassCastException in UnmodifiableMap as well as fix modifying unmodifiable structures through iterators

classpath/java/util/Collections.java

@@ -168,7 +168,7 @@ public class Collections {
     }
 
     public Iterator<T> iterator() {
-      return new SynchronizedIterator(lock, collection.iterator());
+      return new SynchronizedIterator<T>(lock, collection.iterator());
     }
 
     public boolean containsAll(Collection<?> c) {
@@ -335,27 +335,27 @@ public class Collections {
     }
 
     public T set(int index, T value) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public T remove(int index) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean remove(Object o) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean add(T element) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public void add(int index, T element) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public Iterator<T> iterator() {
-      return inner.iterator();
+      return new UnmodifiableIterator<T>(inner.iterator());
     }
 
     public int indexOf(Object value) {
@@ -371,11 +371,11 @@ public class Collections {
     }
 
     public ListIterator<T> listIterator(int index) {
-      return inner.listIterator(index);
+      return new UnmodifiableListIterator<T>(inner.listIterator(index));
     }
 
     public ListIterator<T> listIterator() {
-      return inner.listIterator();
+      return new UnmodifiableListIterator<T>(inner.listIterator());
     }
 
     public int size() {
@@ -387,7 +387,7 @@ public class Collections {
     }
 
     public boolean addAll(Collection<? extends T> collection) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public Object[] toArray() {
@@ -399,15 +399,15 @@ public class Collections {
     }
 
     public void clear() {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean removeAll(Collection<?> c) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean addAll(int startIndex, Collection<? extends T> c) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean containsAll(Collection<?> c) {
@@ -427,7 +427,7 @@ public class Collections {
 	  }
 
     public void clear() {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public boolean containsKey(Object key) {
@@ -455,15 +455,15 @@ public class Collections {
     }
 
     public V put(K key, V value) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public void putAll(Map<? extends K, ? extends V> t) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public V remove(Object key) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
     }
 
     public int size() {
@@ -471,64 +471,132 @@ public class Collections {
     }
 
     public Collection<V> values() {
-      return unmodifiableSet((Set<V>)inner.values());
+      return unmodifiableCollection(inner.values());
     }
   }
-
+  
-  static class UnmodifiableSet<T> implements Set<T> {
+  static class UnmodifiableIterator<T> implements Iterator<T> {
-    private Set<T> inner;
+    private final Iterator<T> inner;
-
+    
-    UnmodifiableSet(Set<T> inner) {
+    UnmodifiableIterator(Iterator<T> inner) {
       this.inner = inner;
     }
-          
+    
-    public boolean add(T element) {
+    @Override
-      throw new UnsupportedOperationException("not supported");
+    public T next() {
+      return inner.next();
     }
 
-    public boolean addAll(Collection<? extends T> collection) {
+    @Override
-      throw new UnsupportedOperationException("not supported");
+    public boolean hasNext() {
+      return inner.hasNext();
     }
 
-    public void clear() {
+    @Override
-      throw new UnsupportedOperationException("not supported");
+    public void remove() {
+      throw new UnsupportedOperationException();
+    }
+  }
+  
+  
+  static class UnmodifiableListIterator<T> extends UnmodifiableIterator<T> 
+                                                   implements ListIterator<T> {
+    private final ListIterator<T> innerListIterator;
+    
+    UnmodifiableListIterator(ListIterator<T> listIterator) {
+      super(listIterator);
+      
+      this.innerListIterator = listIterator;
     }
 
-    public boolean contains(Object element) {
+    @Override
-      return inner.contains(element);
+    public boolean hasPrevious() {
+      return innerListIterator.hasPrevious();
     }
 
-    public boolean isEmpty() {
+    @Override
-      return inner.isEmpty();
+    public T previous() {
+      return innerListIterator.previous();
     }
-
+  }
+  
+  static class UnmodifiableCollection<T> implements Collection<T> {
+    private final Collection<T> inner;
+    
+    UnmodifiableCollection(Collection<T> inner) {
+      this.inner = inner;
+    }
+    
+    @Override
     public Iterator<T> iterator() {
-      return inner.iterator();
+      return new UnmodifiableIterator<T>(inner.iterator());
-    }
-
-    public boolean remove(Object element) {
-      throw new UnsupportedOperationException("not supported");
     }
 
+    @Override
     public int size() {
       return inner.size();
     }
 
-    public Object[] toArray() {
+    @Override
-      return toArray(new Object[size()]);      
+    public boolean isEmpty() {
+      return inner.isEmpty();
     }
 
-    public <S> S[] toArray(S[] array) {
+    @Override
-      return inner.toArray(array);
+    public boolean contains(Object element) {
+      return inner.contains(element);
     }
 
+    @Override
     public boolean containsAll(Collection<?> c) {
       return inner.containsAll(c);
     }
 
+    @Override
+    public boolean add(T element) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends T> collection) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean remove(Object element) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
     public boolean removeAll(Collection<?> c) {
-      throw new UnsupportedOperationException("not supported");
+      throw new UnsupportedOperationException();
-    }     
+    }
+
+    @Override
+    public Object[] toArray() {
+      return inner.toArray();
+    }
+
+    @Override
+    public <S> S[] toArray(S[] array) {
+      return inner.toArray(array);
+    }
+
+    @Override
+    public void clear() {
+      throw new UnsupportedOperationException();
+    }
+  }
+  
+  public static <T> UnmodifiableCollection<T> unmodifiableCollection(Collection<T> collection) {
+    return new UnmodifiableCollection<T>(collection);
+  }
+
+  static class UnmodifiableSet<T> extends UnmodifiableCollection<T> 
+                                  implements Set<T> {
+    UnmodifiableSet(Set<T> inner) {
+      super(inner);
+    }  
   }
   
   public static <T> Set<T> unmodifiableSet(Set<T> hs) {

test/Collections.java

@@ -0,0 +1,26 @@
+import java.util.Collection;
+import java.util.Map;
+
+public class Collections {
+  public static void main(String[] args) {
+    testValues();
+  }
+  
+  @SuppressWarnings("rawtypes")
+  private static void testValues() {
+    Map testMap = java.util.Collections.unmodifiableMap(java.util.Collections.emptyMap());
+    Collection values = testMap.values();
+    
+    if (values == null) {
+      throw new NullPointerException();
+    }
+    
+    try {
+      values.clear();
+      
+      throw new IllegalStateException("Object should be immutable, exception should have thrown");
+    } catch (Exception e) {
+      // expected
+    }
+  }
+}