Row.java

package org.sigmah.client.ui.view.project.logframe.grid;

/*
 * #%L
 * Sigmah
 * %%
 * Copyright (C) 2010 - 2016 URD
 * %%
 * This program 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.
 * 
 * This program 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 this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import com.google.gwt.user.client.ui.Widget;

/**
 * Represents a row.
 * 
 * @param <T>
 *          The type of the user object displayed by this row.
 * @author tmi (v1.3)
 * @author Denis Colliot (dcolliot@ideia.fr) (v2.0)
 */
public abstract class Row<T> {

	/**
	 * Define an element that can be positionable in a group of rows.
	 * 
	 * @author tmi (v1.3)
	 * @author Denis Colliot (dcolliot@ideia.fr) (v2.0)
	 */
	public static interface Positionable {

		/**
		 * Sets the position of this row inside its group.
		 * 
		 * @param position
		 *          The new position.
		 */
		void setPosition(Integer position);

	}

	/**
	 * The user object.
	 */
	private final T userObject;

	/**
	 * The group in which this row is inserted.
	 */
	private RowsGroup<?> parent;

	/**
	 * Initializes the row.
	 * 
	 * @param userObject
	 *          The user object.
	 */
	public Row(T userObject) {
		this.userObject = userObject;
	}

	/**
	 * Sets the position of this row inside its group.
	 * 
	 * @param position
	 *          The new position, can be <code>null</code> if the row doesn't belong to a group anymore.
	 */
	protected void setPosition(Integer position) {
		if (userObject != null) {
			if (userObject instanceof Positionable) {
				((Positionable) userObject).setPosition(position);
			}
		}
	}

	/**
	 * Gets the user object.
	 * 
	 * @return The user object.
	 */
	public T getUserObject() {
		return userObject;
	}

	/**
	 * Gets the parent group.
	 * 
	 * @return The parent group.
	 */
	public RowsGroup<?> getParent() {
		return parent;
	}

	/**
	 * Sets the parent group.
	 * 
	 * @param parent
	 *          The new parent group.
	 */
	public void setParent(RowsGroup<?> parent) {
		this.parent = parent;
	}

	@Override
	public boolean equals(Object obj) {

		if (obj == null) {
			return false;
		}

		if (!(obj instanceof Row)) {
			return false;
		}

		@SuppressWarnings("unchecked")
		final Row<T> other = (Row<T>) obj;
		return getId() == other.getId();
	}

	@Override
	public String toString() {
		return "[Row] code #" + String.valueOf(getId());
	}

	@Override
	public int hashCode() {
		return getId();
	}

	/**
	 * Gets the unique code which identifies the row for the entire table.
	 * 
	 * @return The unique code to identify the row.
	 */
	public int getId() {
		return getId(userObject);
	}

	/**
	 * Gets the unique code which identifies the row for the entire table.
	 * 
	 * @param userObject
	 *          The user object.
	 * @return The unique code to identify the row.
	 */
	public abstract int getId(T userObject);

	/**
	 * Gets the widget which must be displayed at the given column index.
	 *
	 * If there is no widget to display at this index, the method must return <code>null</code>. In this case, the
	 * right-adjacent column will be merged with this column.
	 * 
	 * @param column
	 *          The column index.
	 * @return The widget if any, <code>null</code> otherwise.
	 */
	public Widget getWidgetAt(int column) {
		return getWidgetAt(column, userObject);
	}

	/**
	 * Gets the widget which must be displayed at the given column index.
	 *
	 * If there is no widget to display at this index, the method must return <code>null</code>. In this case, the
	 * right-adjacent column will be merged with this column.
	 * 
	 * @param column
	 *          The column index.
	 * @param userObject
	 *          The user object.
	 * @return The widget if any, <code>null</code> otherwise.
	 */
	public abstract Widget getWidgetAt(int column, T userObject);

	/**
	 * Returns if the property displayed at the given column index for this row is similar (or equals) at the same
	 * property for the <code>other</code> row.
	 * By default this method returns false.
	 * 
	 * @param column
	 *          The column index.
	 * @param userObject
	 *          The user object.
	 * @param other
	 *          The user object to compare (never <code>null</code>).
	 * @return If the two rows properties are similar.
	 */
	public boolean isSimilar(int column, T userObject, T other) {
		return false;
	}
}