Java tutorial
/* * Copyright 2010 JBoss Inc * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.optaplanner.examples.pas.domain.solver; import java.io.Serializable; import java.util.Comparator; import org.apache.commons.lang.builder.CompareToBuilder; import org.optaplanner.examples.pas.domain.Bed; import org.optaplanner.examples.pas.domain.Department; import org.optaplanner.examples.pas.domain.Room; public class BedStrengthComparator implements Comparator<Bed>, Serializable { public int compare(Bed a, Bed b) { if (a == null) { if (b == null) { return 0; } return -1; } else if (b == null) { return 1; } Room aRoom = a.getRoom(); Department aDepartment = aRoom.getDepartment(); Room bRoom = b.getRoom(); Department bDepartment = bRoom.getDepartment(); return new CompareToBuilder() // null minimumAge is stronger .append(aDepartment.getMinimumAge() == null, bDepartment.getMinimumAge() == null) // null maximumAge is stronger .append(aDepartment.getMaximumAge() == null, bDepartment.getMaximumAge() == null) // Descending, low minimumAge is stronger .append(bDepartment.getMinimumAge(), aDepartment.getMinimumAge()) // High maximumAge is stronger .append(aDepartment.getMaximumAge(), bDepartment.getMaximumAge()) .append(aRoom.getRoomEquipmentList().size(), bRoom.getRoomEquipmentList().size()) .append(aRoom.getRoomSpecialismList().size(), bRoom.getRoomSpecialismList().size()) .append(bRoom.getCapacity(), aRoom.getCapacity()) // Descending (smaller rooms are stronger) .append(a.getId(), b.getId()).toComparison(); } }