SideConstraint.java

package org.andork.awt.layout;

import java.awt.Component;

/**
 * Info for constraining to a fixed offset from a given side of a given
 * component.
 *
 * @author James
 */
public class SideConstraint {
	/**
	 * the component whose side to constrain to.
	 */
	final Component targetComponent;
	/**
	 * the side of {@link #targetComponent} to constrain to.
	 */
	final Side targetSide;
	/**
	 * the offset from {@link #targetSide}; positive values are downward (if
	 * {@link #targetSide} is horizontal) or to the right (if
	 * {@link #targetSide} is vertical).
	 */
	final int offset;

	/**
	 * Creates a {@code SideConstraint}.
	 *
	 * @param targetComponent
	 *            the component whose side to constrain to.
	 * @param targetSide
	 *            the side of {@code targetComponent} to constrain to.
	 * @param offset
	 *            the offset from {@code targetSide}; positive values are
	 *            downward (if {@code targetSide} is horizontal) or to the right
	 *            (if {@code targetSide} is vertical).
	 */
	public SideConstraint(Component targetComponent, Side targetSide, int offset) {
		super();
		this.targetComponent = targetComponent;
		this.targetSide = targetSide;
		this.offset = offset;
	}

	/**
	 * @return the current location of this {@link SideConstraint}, which is
	 *         {@link #offset} pixels away from the current
	 *         {@link Side#location(Component)} location of {@link #targetSide}
	 *         of {@link #targetComponent}.
	 */
	public int location() {
		return targetSide.location(targetComponent) + offset;
	}
}