WeightRestriction.java

package edu.kit.pse.ws2013.routekit.map;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import edu.kit.pse.ws2013.routekit.profiles.Profile;

/**
 * A restriction of the vehicle weight.
 */
public class WeightRestriction extends Restriction {
	private static Map<Integer, WeightRestriction> instances = new HashMap<>();

	/**
	 * Returns an instance of this class for the specified weight.
	 * 
	 * @param weight
	 *            the maximum allowed weight of the vehicle (in kilograms)
	 * @return the desired instance
	 * @throws IllegalArgumentException
	 *             if {@code weight} is negative
	 */
	public static Restriction getInstance(int weight) {
		if (weight < 0) {
			throw new IllegalArgumentException();
		}

		if (!instances.containsKey(weight)) {
			instances.put(weight, new WeightRestriction(weight));
		}
		return instances.get(weight);
	}

	private final int weight;

	private WeightRestriction(int weight) {
		this.weight = weight;
	}

	@Override
	public boolean allows(Profile profile) {
		return profile.getWeight() <= weight;
	}

	@Override
	protected void saveInternal(DataOutput out) throws IOException {
		out.writeInt(weight);
	}

	protected static Restriction loadInternal(DataInput in) throws IOException {
		return getInstance(in.readInt());
	}
}