LanguageContributor.java

/*
Copyright (c) 2009 Andr� Arnold.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License v1.0
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/epl-v10.html

Contributors:
    Andr� Arnold - initial API and implementation
 */
package org.eclipse.xtend.middleend;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.eclipse.emf.mwe.core.ConfigurationException;
import org.eclipse.xtend.middleend.plugins.LanguageSpecificMiddleEnd;
import org.eclipse.xtend.middleend.plugins.LanguageSpecificMiddleEndFactory;

public class LanguageContributor {
	
    private static final Log _log = LogFactory.getLog (LanguageContributor.class);

    public final static LanguageContributor INSTANCE = new LanguageContributor (); 
	
	private final Map<String, LanguageSpecificMiddleEndFactory> _middleEndContributions = new HashMap<String, LanguageSpecificMiddleEndFactory> ();
	
	private LanguageContributor () {
	}
	
	
	public void addLanguageContribution (Class<? extends LanguageSpecificMiddleEndFactory> middleEndFactoryClass) throws ConfigurationException {
		try {
			final LanguageSpecificMiddleEndFactory factory = middleEndFactoryClass.newInstance ();
			_middleEndContributions.put (factory.getName(), factory);
		} catch (InstantiationException e) {
			throw new ConfigurationException(e);
		} catch (IllegalAccessException e) {
			throw new ConfigurationException(e);
		}
	}
	
	public Collection<LanguageSpecificMiddleEndFactory> getLanguageContributions () {
		return _middleEndContributions.values();
	}
	
	public LanguageSpecificMiddleEndFactory getLanguageContributionByName (String middleEndName) {
		return _middleEndContributions.get (middleEndName);
	}

    public List<LanguageSpecificMiddleEnd> getFreshMiddleEnds (Map<Class<?>, Object> specificParams) {
        
        final List<LanguageSpecificMiddleEnd> result = new ArrayList<LanguageSpecificMiddleEnd>();

        for (LanguageSpecificMiddleEndFactory factory: _middleEndContributions.values()) {
            try {
                result.add (factory.create (specificParams.get (factory.getClass())));
            }
            catch (IllegalArgumentException exc) {
                // this is the official way for an implementation to withdraw from the pool for this call
                _log.debug ("middle end implementation " + factory.getName() + " says it is not available: " + exc.getMessage());
            }
        }
        
        return result;
    }
}