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'databene commons' is an open source Java library by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * Licensed 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.databene.commons.converter;

import org.databene.commons.ArrayUtil;
import org.databene.commons.ConversionException;
import org.databene.commons.Converter;

/**
 * Converts arrays from one component type to arrays of another component type.
 * If there are no converters registered, it only transforms the array type.
 * If there is a single converter, all elements are converted with the same converter.
 * If there are several converters, the number of converters and array elements are 
 * assumed to be equal and each element is converted with the converter of the same index.
 * Created: 07.06.2007 14:35:18
 * @param  the object type to convert from
 * @param  the object type to convert to
 * @author Volker Bergmann
 */
public class ArrayConverter extends MultiConverterWrapper implements Converter {

    private Class targetComponentType;
    private Class sourceType;
    private Class targetType;

    @SuppressWarnings("unchecked")
    public ArrayConverter(Class sourceComponentType, Class targetComponentType, Converter ... converters) {
    	super(converters);
        this.targetComponentType = targetComponentType;
        this.sourceType = ArrayUtil.arrayType(sourceComponentType);
        this.targetType = ArrayUtil.arrayType(targetComponentType);
    }

	@Override
	public Class getSourceType() {
	    return sourceType;
    }

	@Override
	public Class getTargetType() {
	    return targetType;
    }
    
	/** 
	 * If there are no converters, it only transforms the array type; 
	 * if there is a single converter, all elements are converted with the same converter;
	 * if there are several converters, the number of converters and array elements are 
	 * assumed to be equal and each element is converted with the converter of the same index.
	 */
    @Override
	public T[] convert(S[] sourceValues) throws ConversionException {
        if (sourceValues == null)
            return null;
        if (components.length == 0)
        	return convertWith(null, targetComponentType, sourceValues);
        else if (components.length == 1)
        	return convertWith(components[0], targetComponentType, sourceValues);
        else {
        	if (sourceValues.length != components.length)
        		throw new IllegalArgumentException("Array has a different size than the converter list");
            T[] result = ArrayUtil.newInstance(targetComponentType, components.length);
            for (int i = 0; i < components.length; i++)
	            result[i] = components[i].convert(sourceValues[i]);
            return result;
        }
    }

    /** Converts all array elements with the same {@link Converter}. 
     * @param converter the converter to apply
     * @param componentType the component type of the result array
     * @param sourceValues the source values to convert
     * @return an array with the mapped values
	 * @param  the object type to convert from
	 * @param  the object type to convert to
     * @throws ConversionException if conversion fails */
    public static  T[] convertWith(Converter converter, Class componentType, S[] sourceValues) throws ConversionException {
        T[] result = ArrayUtil.newInstance(componentType, sourceValues.length);
        for (int i = 0; i < sourceValues.length; i++) {
        	Object tmp = (converter != null ? converter.convert(sourceValues[i]) : sourceValues[i]);
            result[i] = AnyConverter.convert(tmp, componentType);
        }
        return result;
    }

}