//
// Copyright (C) 2006 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA). All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3. The NOSA has been approved by the Open Source
// Initiative. See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package gov.nasa.jpf.util;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* utility class for JPF internal linked lists that are tail-immutable
*/
public class ImmutableList<E> implements Iterable<E> {
static class IteratorImpl<E> implements Iterator<E> {
private ImmutableList<E> next;
private IteratorImpl(ImmutableList<E> list){
next = list;
}
public boolean hasNext() {
return (next != null);
}
public E next() {
if (next != null){
E elem = next.head;
next = next.tail;
return elem;
} else {
throw new NoSuchElementException();
}
}
public void remove() {
throw new UnsupportedOperationException("can't remove elements from ImmutableList");
}
}
public final E head;
public final ImmutableList<E> tail;
public ImmutableList(E data, ImmutableList<E> tail) {
this.head = data;
this.tail = tail;
}
public Iterator<E> iterator() {
return new IteratorImpl<E>(this);
}
public boolean contains (E object){
for (E e : this){
if (e.equals(object)){
return true;
}
}
return false;
}
}