ArrayTypeHandler.java

/*
 * Copyright (c) 2002 Cunningham & Cunningham, Inc.
 * Copyright (c) 2009-2015 by Jochen Wierum & Cologne Intelligence
 *
 * This file is part of FitGoodies.
 *
 * FitGoodies is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * FitGoodies is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with FitGoodies.  If not, see <http://www.gnu.org/licenses/>.
*/

package de.cologneintelligence.fitgoodies.typehandler;

import java.lang.reflect.Array;
import java.text.ParseException;
import java.util.StringTokenizer;

/**
 * If the destination type is an array, this adapter handles it.
 * It splits the input at commas and converts each part into an array element.
 */
public class ArrayTypeHandler extends TypeHandler {
	/**
	 * {@code TypeAdapter} which handles the array items.
	 */
	private TypeHandler componentAdapter;

	/**
	 * Creates a new TypeAdapter which can read arrays.
	 * In contrast to the fit TypeAdapter, this one is able to process registered
	 * Types of array.
	 *
	 * @param convertParameter column/row parameter
	 * @param componentAdapter adapter to parse the array content
	 */
	public ArrayTypeHandler(final String convertParameter, TypeHandler componentAdapter) {
		super(convertParameter);
		this.componentAdapter = componentAdapter;
	}

	@Override
	public Class getType() {
		return null;
	}

	/**
	 * Converts a {@code String} into a {@code Array}.
	 *
	 * @param s the {@code String} to convert
	 * @return an {@code Array} which contains {@code s}
	 */
	@Override
	public Object unsafeParse(final String s) throws ParseException {
		final StringTokenizer t = new StringTokenizer(s, ",");
		final Object array = Array.newInstance(componentAdapter.getType(), t.countTokens());
		for (int i = 0; t.hasMoreTokens(); i++) {
			Array.set(array, i, componentAdapter.parse(t.nextToken().trim()));
		}
		return array;
	}

	/**
	 * Returns the String representation of the array. The result is a comma
	 * separated list of all items. The items are converted to Strings using
	 * an item-specific type adapter.
	 *
	 * @param o Array to convert
	 * @return {@code o} as a String
	 */
	@SuppressWarnings("unchecked")
	@Override
	public String toString(final Object o) {
		if (o == null) {
			return "";
		}

		final int length = Array.getLength(o);
		final StringBuilder b = new StringBuilder(5 * length);
		for (int i = 0; i < length; i++) {
			b.append(componentAdapter.toString(Array.get(o, i)));
			if (i < length - 1) {
				b.append(", ");
			}
		}
		return b.toString();
	}

	/**
	 * Checks whether two Arrays {@code a} and {@code b} are
	 * equal.
	 * <p>
	 * A type specific {@code TypeAdapter} is used to compare the items.
	 *
	 * @param a first array
	 * @param b second array
	 * @return {@code true} if all items are equal, {@code false} otherwise
	 */
	@SuppressWarnings("unchecked")
	@Override
	public boolean unsafeEquals(Object a, Object b) {
		final int length = Array.getLength(a);
		if (length != Array.getLength(b)) {
			return false;
		}
		for (int i = 0; i < length; i++) {
			if (!componentAdapter.unsafeEquals(Array.get(a, i), Array.get(b, i))) {
				return false;
			}
		}
		return true;
	}
}