/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.atlas.lib;
import java.util.ArrayList ;
import java.util.Collections ;
import java.util.Comparator ;
import java.util.Enumeration ;
import java.util.Iterator ;
import java.util.List ;
import java.util.Properties ;
/** Sorted output */
public class PropertiesSorted extends Properties
{
private Comparator<String> comparator = null ;
//public SortedProperties() { super() ; }
public PropertiesSorted(Comparator<String> comparator)
{
super() ;
this.comparator = comparator ;
}
@SuppressWarnings({"unchecked", "rawtypes"})
@Override
public synchronized Enumeration<Object> keys()
{
// Old world - enumeration, untyped. But we know they are strings (Propetries hides non-strings in get)
Enumeration<Object> keys = super.keys() ;
List<String> keys2 = new ArrayList<>(super.size()) ;
for( ; keys.hasMoreElements() ; )
{
Object obj = keys.nextElement() ;
if ( obj instanceof String )
keys2.add((String)obj);
}
// Keys are comparable because they are strings.
if ( comparator == null )
Collections.sort(keys2);
else
Collections.sort(keys2, comparator) ;
return new IteratorToEnumeration(keys2.listIterator()) ;
}
static class IteratorToEnumeration<T> implements Enumeration<T>
{
private Iterator<T> iterator ;
public IteratorToEnumeration(Iterator<T> iterator)
{
this.iterator = iterator ;
}
@Override
public boolean hasMoreElements()
{
return iterator.hasNext() ;
}
@Override
public T nextElement()
{
return iterator.next();
}
}
}