OrderBuilder.java

package org.opennms.core.criteria;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;

import org.opennms.core.utils.LogUtils;

public final class OrderBuilder {
	private final LinkedHashSet<Order> m_orders = new LinkedHashSet<Order>();
	private String m_lastAttribute = null;

	/**
	 * Append an order object to the end of the order list.
	 * @param order the order object to append
	 * @return whether it was added (true if added, false if already exists/ignored)
	 */
	boolean append(final Order order) {
		if (m_orders.add(order)) {
			m_lastAttribute = order.getAttribute();
			return true;
		} else {
			m_lastAttribute = null;
			return false;
		}
	}

	public void clear() {
		m_orders.clear();
	}

	public Collection<Order> getOrderCollection() {
		// make a copy so the internal one can't be modified outside of the builder
		return new ArrayList<Order>(m_orders);
	}

	public void asc() {
		synchronized (m_orders) {
			if (m_orders.isEmpty()) {
				LogUtils.debugf(this, "asc() called, but no orderBy has been specified."); 
			} else if (m_lastAttribute == null) {
				LogUtils.debugf(this, "asc() called on an attribute that can't be changed.");
			} else {
				for (final Order o : m_orders) {
					if (o.getAttribute().equals(m_lastAttribute)) {
						m_orders.remove(o);
						m_orders.add(Order.asc(m_lastAttribute));
						break;
					}
				}
			}
		}
	}

	public void desc() {
		synchronized (m_orders) {
			if (m_orders.isEmpty()) {
				LogUtils.debugf(this, "desc() called, but no orderBy has been specified."); 
			} else if (m_lastAttribute == null) {
				LogUtils.debugf(this, "desc() called on an attribute that can't be changed.");
			} else {
				for (final Order o : m_orders) {
					if (o.getAttribute().equals(m_lastAttribute)) {
						m_orders.remove(o);
						m_orders.add(Order.desc(m_lastAttribute));
						break;
					}
				}
			}
		}
	}

}