Java tutorial
/******************************************************************************* * This file is part of OpenNMS(R). * * Copyright (C) 2007-2012 The OpenNMS Group, Inc. * OpenNMS(R) is Copyright (C) 1999-2012 The OpenNMS Group, Inc. * * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc. * * OpenNMS(R) 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. * * OpenNMS(R) 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 OpenNMS(R). If not, see: * http://www.gnu.org/licenses/ * * For more information contact: * OpenNMS(R) Licensing <license@opennms.org> * http://www.opennms.org/ * http://www.opennms.com/ *******************************************************************************/ package org.opennms.ng.dao.support; import java.util.Comparator; import java.util.SortedSet; import java.util.TreeSet; import org.opennms.netmgt.model.AttributeStatistic; import org.opennms.netmgt.model.AttributeStatisticVisitorWithResults; import org.opennms.netmgt.model.OnmsAttribute; import org.springframework.beans.factory.InitializingBean; import org.springframework.util.Assert; /** * <p>BottomNAttributeStatisticVisitor class.</p> * * @author <a href="mailto:dj@opennms.org">DJ Gregor</a> * @version $Id: $ */ public class BottomNAttributeStatisticVisitor implements AttributeStatisticVisitorWithResults, InitializingBean { private Integer m_count; private SortedSet<AttributeStatistic> m_results = new TreeSet<AttributeStatistic>( new AttributeStatisticComparator()); protected Comparator<Double> m_comparator = new DoubleComparator(); /** * <p>Constructor for BottomNAttributeStatisticVisitor.</p> */ public BottomNAttributeStatisticVisitor() { super(); } /** {@inheritDoc} */ @Override public void visit(OnmsAttribute attribute, double statistic) { Assert.notNull(attribute, "attribute argument must not be null"); m_results.add(new AttributeStatistic(attribute, statistic)); } /** * <p>afterPropertiesSet</p> * * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet() */ @Override public void afterPropertiesSet() { Assert.state(m_count != null, "property count must be set to a non-null value"); } /** * <p>getCount</p> * * @return a {@link Integer} object. */ @Override public Integer getCount() { return m_count; } /** {@inheritDoc} */ @Override public void setCount(Integer count) { m_count = count; } /** * <p>getResults</p> * * @return top attribute statistics (up to getCount() number) */ @Override public SortedSet<AttributeStatistic> getResults() { SortedSet<AttributeStatistic> top = new TreeSet<AttributeStatistic>(new AttributeStatisticComparator()); for (AttributeStatistic stat : m_results) { top.add(stat); if (top.size() >= m_count) { break; } } return top; } /** * <p>getComparator</p> * * @return a {@link java.util.Comparator} object. */ public Comparator<Double> getComparator() { return m_comparator; } /** * <p>setComparator</p> * * @param comparator a {@link java.util.Comparator} object. */ public void setComparator(Comparator<Double> comparator) { m_comparator = comparator; } public class AttributeStatisticComparator implements Comparator<AttributeStatistic> { /** * @see java.util.Comparator#compare(Object, Object) */ @Override public int compare(AttributeStatistic o1, AttributeStatistic o2) { int diff; diff = getComparator().compare(o1.getStatistic(), o2.getStatistic()); if (diff != 0) { return diff; } diff = o1.getAttribute().getResource().getId() .compareToIgnoreCase(o2.getAttribute().getResource().getId()); if (diff != 0) { return diff; } return Integer.valueOf(o1.getAttribute().hashCode()).compareTo(o2.getAttribute().hashCode()); } } public class DoubleComparator implements Comparator<Double> { /** * @see java.util.Comparator#compare(Object, Object) */ @Override public int compare(Double o1, Double o2) { return o1.compareTo(o2); } } }