QMapObject.java

package org.andork.tracker.model;

import java.util.Map;

import org.andork.tracker.model.QSpec.Property;

/**
 * {@code QObject} (along with {@link QSpec}) provides the closest functionality
 * to reflection on a POJO that is possible without actually using reflection.
 * It also provides property {@linkplain #changeSupport() change support} that
 * will notify listeners of any property changes, so that you don't have to
 * write any boilerplate property change notification code.<br>
 * <br>
 * The Q doesn't stand for anything.
 *
 * @author andy.edwards
 * @param <S>
 *            the type of {@link QSpec} for this object.
 */
public abstract class QMapObject<S extends QSpec> extends QObject<S> {
	final Map<Property<?>, Object> values;

	public QMapObject(S spec, Map<Property<?>, Object> values) {
		super(spec);
		if (!values.isEmpty()) {
			throw new IllegalArgumentException("values must be empty");
		}
		this.values = values;
		for (Property<?> property : spec.propertyList) {
			Object initValue = property.initValue().get();
			if (initValue != null) {
				values.put(property, initValue);
			}
		}
	}

	protected abstract Map<Property<?>, Object> createValuesMap();

	@Override
	@SuppressWarnings("unchecked")
	public <T> T doGet(Property<T> property) {
		return (T) values.get(property);
	}

	@Override
	@SuppressWarnings("unchecked")
	public <T> T doSet(Property<T> property, T newValue) {
		T oldValue = newValue == null ? (T) values.remove(this) : (T) values.put(property, newValue);
		return oldValue;
	}
}