constructorhandler.java

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/*
 * Created on Mar 1, 2005
 */
package org.flexdock.plaf.resources;

import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.StringTokenizer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * @author Christopher Butler
 */
public class ConstructorHandler extends ResourceHandler {
    private static Log log = LogFactory.getLog(ConstructorHandler.class);
    
	private Constructor constructor;

	public ConstructorHandler(Constructor constructor) {
		this.constructor = constructor;
	}

	public Object getResource(String stringValue) {
		Object[] arguments = getArguments(stringValue);
		try {
			return constructor.newInstance(arguments);
		} catch(Exception e) {
			log.debug(e.getMessage(),e);
			return null;
		}
	}
	
	private Object[] getArguments(String data) {
		String[] supplied = parseArguments(data);
		Object[] arguments = new Object[supplied.length];
		Class[] paramTypes = constructor.getParameterTypes();
		if(arguments.length!=paramTypes.length)
			throw new IllegalArgumentException("Cannot match '" + data + "' to constructor " + constructor + ".");
		
		for(int i=0; i<paramTypes.length; i++) {
			arguments[i] = toObject(supplied[i], paramTypes[i]);
		}
		return arguments;
	}
	
	private Object toObject(String data, Class type) {
		if(type==int.class)
			return new Integer(data);
		if(type==long.class)
			return new Long(data);
		if(type==boolean.class)
			return new Boolean(data);
		if(type==float.class)
			return new Float(data);
		if(type==double.class)
			return new Double(data);
		if(type==byte.class)
			return new Byte(data);
		if(type==short.class)
			return new Short(data);
		
		return data;
	}
	
	private String[] parseArguments(String data) {
		if(!data.endsWith(","))
			data += ",";
		
		ArrayList args = new ArrayList();
		StringTokenizer st = new StringTokenizer(data, ",");
		while(st.hasMoreTokens()) {
			args.add(st.nextToken().trim());
		}
		return (String[])args.toArray(new String[0]);
	}
}