jetty-webapp/src/main/java/org/eclipse/jetty/webapp/AbsoluteOrdering.java

//
//  ========================================================================
//  Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.webapp;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.jetty.util.resource.Resource;

/**
 * AbsoluteOrdering
 *
 */
public class AbsoluteOrdering implements Ordering
{
    public static final String OTHER = "@@-OTHER-@@";
    protected List<String> _order = new ArrayList<String>();
    protected boolean _hasOther = false;
    protected MetaData _metaData;

    public AbsoluteOrdering (MetaData metaData)
    {
        _metaData = metaData;
    }
    
    @Override
    public List<Resource> order(List<Resource> jars)
    {           
        List<Resource> orderedList = new ArrayList<Resource>();
        List<Resource> tmp = new ArrayList<Resource>(jars);
      
        //1. put everything into the list of named others, and take the named ones out of there,
        //assuming we will want to use the <other> clause
        Map<String,FragmentDescriptor> others = new HashMap<String,FragmentDescriptor>(_metaData.getNamedFragments());
        
        //2. for each name, take out of the list of others, add to tail of list
        int index = -1;
        for (String item:_order)
        {
            if (!item.equals(OTHER))
            {
                FragmentDescriptor f = others.remove(item);
                if (f != null)
                {
                    Resource jar = _metaData.getJarForFragment(item);
                    orderedList.add(jar); //take from others and put into final list in order, ignoring duplicate names
                    //remove resource from list for resource matching name of descriptor
                    tmp.remove(jar);
                }
            }
            else
                index = orderedList.size(); //remember the index at which we want to add in all the others
        }
        
        //3. if <other> was specified, insert rest of the fragments 
        if (_hasOther)
        {
            orderedList.addAll((index < 0? 0: index), tmp);
        }
        
        return orderedList;
    }
    
    public void add (String name)
    {
        _order.add(name); 
    }
    
    public void addOthers ()
    {
        if (_hasOther)
            throw new IllegalStateException ("Duplicate <other> element in absolute ordering");
        
        _hasOther = true;
        _order.add(OTHER);
    }
}