/*
* Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
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package com.sun.corba.se.impl.ior ;
import java.util.Collection ;
import java.util.List ;
import java.util.AbstractList ;
import java.util.ListIterator ;
import java.util.Iterator ;
import com.sun.corba.se.spi.ior.MakeImmutable ;
/** Simple class that delegates all List operations to
* another list. It also can be frozen, which means that
* a number of operations can be performed on the list,
* and then the list can be made immutable, so that no
* further changes are possible. A FreezableList is frozen
* using the makeImmutable method.
*/
public class FreezableList extends AbstractList {
private List delegate = null ;
private boolean immutable = false ;
public boolean equals( Object obj )
{
if (obj == null)
return false ;
if (!(obj instanceof FreezableList))
return false ;
FreezableList other = (FreezableList)obj ;
return delegate.equals( other.delegate ) &&
(immutable == other.immutable) ;
}
public int hashCode()
{
return delegate.hashCode() ;
}
public FreezableList( List delegate, boolean immutable )
{
this.delegate = delegate ;
this.immutable = immutable ;
}
public FreezableList( List delegate )
{
this( delegate, false ) ;
}
public void makeImmutable()
{
immutable = true ;
}
public boolean isImmutable()
{
return immutable ;
}
public void makeElementsImmutable()
{
Iterator iter = iterator() ;
while (iter.hasNext()) {
Object obj = iter.next() ;
if (obj instanceof MakeImmutable) {
MakeImmutable element = (MakeImmutable)obj ;
element.makeImmutable() ;
}
}
}
// Methods overridden from AbstractList
public int size()
{
return delegate.size() ;
}
public Object get(int index)
{
return delegate.get(index) ;
}
public Object set(int index, Object element)
{
if (immutable)
throw new UnsupportedOperationException() ;
return delegate.set(index, element) ;
}
public void add(int index, Object element)
{
if (immutable)
throw new UnsupportedOperationException() ;
delegate.add(index, element) ;
}
public Object remove(int index)
{
if (immutable)
throw new UnsupportedOperationException() ;
return delegate.remove(index) ;
}
// We also override subList so that the result is a FreezableList.
public List subList(int fromIndex, int toIndex)
{
List list = delegate.subList(fromIndex, toIndex) ;
List result = new FreezableList( list, immutable ) ;
return result ;
}
}