/**
 * Portions Copyright 2006 DFKI GmbH.
 * Portions Copyright 2001 Sun Microsystems, Inc.
 * Portions Copyright 1999-2001 Language Technologies Institute, 
 * Carnegie Mellon University.
 * All Rights Reserved.  Use is subject to license terms.
 * 
 * Permission is hereby granted, free of charge, to use and distribute
 * this software and its documentation without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of this work, and to
 * permit persons to whom this work is furnished to do so, subject to
 * the following conditions:
 * 
 * 1. The code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 * 2. Any modifications must be clearly marked as such.
 * 3. Original authors' names are not deleted.
 * 4. The authors' names are not used to endorse or promote products
 *    derived from this software without specific prior written
 *    permission.
 *
 * DFKI GMBH AND THE CONTRIBUTORS TO THIS WORK DISCLAIM ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DFKI GMBH NOR THE
 * CONTRIBUTORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 * THIS SOFTWARE.
 */

package marytts.unitselection.weightingfunctions;

import java.util.HashMap;
import java.util.Map;

/**
 * This class connects weighting function names with the actual instances of the weighting functions.
 * 
 * @author sacha
 * 
 */
public class WeightFunctionManager {

	public static Map weightFuncMap;

	static {
		weightFuncMap = new HashMap();
		weightFuncMap.put("linear", new WeightingFunction.linear());
		weightFuncMap.put("step", new WeightingFunction.step());
	}

	/**
	 * Dummy empty contructor.
	 */
	public WeightFunctionManager() {
	}

	/**
	 * Accessor for the hash map mapping names to interface instances.
	 * 
	 * @return a hash map.
	 */
	public static Map getWeightFunc() {
		return weightFuncMap;
	}

	/**
	 * Returns the weighting function from its name.
	 * 
	 * @param funcName
	 *            The name of the weighting function.
	 * @return an interface to a weighting function.
	 */
	public WeightFunc getWeightFunction(String funcName) {
		/* Split the string in 2 parts: function name plus parameters */
		String[] strPart = funcName.split("\\s", 2);
		WeightFunc wf = (WeightFunc) weightFuncMap.get(strPart[0]);
		/* If the function asked for does not exist, inform the user and throw an exception. */
		if (wf == null) {
			String[] known = (String[]) weightFuncMap.keySet().toArray(new String[0]);
			String strKnown = known[0];
			for (int i = 1; i < known.length; i++) {
				strKnown = strKnown + "; " + known[i];
			}
			strKnown = strKnown + ".";
			throw new RuntimeException("The weighting manager was asked for the unknown weighting function type [" + funcName
					+ "]. Known types are: " + strKnown);
		}
		/* If the function has a parameter, parse and set it */
		// TODO: This is not thread-safe! What if several threads call wf.setParam() with different values?
		if (strPart.length > 1)
			wf.setParam(strPart[1]);
		/* Return the functionś interface */
		return (wf);
	}

}