Java tutorial
/* * This file is part of LibrePlan * * Copyright (C) 2009-2010 Fundacin para o Fomento da Calidade Industrial e * Desenvolvemento Tecnolxico de Galicia * Copyright (C) 2010-2011 Igalia, S.L. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.zkoss.ganttz.data; import java.util.Arrays; import java.util.Collections; import java.util.Date; import org.apache.commons.lang3.Validate; import org.joda.time.LocalDate; import org.zkoss.ganttz.IDatesMapper; /** * <p> * It's a special purpose date type for ganttzk library. Since ganttzk could be * used by several implementations it must have freedom to allow different * underlying implementations. * </p> * <p> * There are two base cases: * <ul> * <li>the {@link LocalDateBased} one that is basically a LocalDate date. It's * normally used to receive values from interface. For example when moving a * Task a {@link LocalDateBased} date is generated with the position the task * has been moved.</li> * <li>the {@link CustomDate}. This is one intended to be overridden by the user * of ganttzk. * </ul> * These base cases are used as a basis for a form of degenerate pattern * matching in {@link #byCases(ICases)}, resembling the visitor pattern. This * scheme allows ganttzk to work with both kinds of dates and perform different * operations depending on the type. * </p> * <p> * Please note that ganttzk is intended to work with only one type of * {@link CustomDate} at the same time. It's a bad idea to mix several types of * CustomDate. * </p> * * @author scar Gonzlez Fernndez */ public abstract class GanttDate implements Comparable<GanttDate> { public static LocalDateBased createFrom(Date date) { if (date == null) { return null; } return createFrom(LocalDate.fromDateFields(date)); } public static LocalDateBased createFrom(LocalDate localDate) { if (localDate == null) { return null; } return new LocalDateBased(localDate); } public static GanttDate min(GanttDate... dates) { return Collections.min(Arrays.asList(dates)); } public static GanttDate max(GanttDate... dates) { return Collections.max(Arrays.asList(dates)); } @Override public final boolean equals(Object obj) { if (obj == this) { return true; } if (obj instanceof GanttDate) { GanttDate other = (GanttDate) obj; return isEqualsTo(other); } return false; } protected abstract boolean isEqualsTo(GanttDate other); @Override public abstract int hashCode(); public interface ICases<R> { R on(LocalDateBased localDateBased); R on(CustomDate customType); } public static abstract class Cases<T extends CustomDate, R> implements ICases<R> { private final Class<T> klass; public Cases(Class<T> klass) { Validate.notNull(klass); this.klass = klass; } @Override public R on(CustomDate customType) { return onCustom(klass.cast(customType)); } protected abstract R onCustom(T customType); } public abstract <R> R byCases(ICases<R> cases); /** * Converts this {@link GanttDate} to a date that is the start of the day * represented by this {@link GanttDate} */ public abstract Date toDayRoundedDate(); public abstract LocalDate toLocalDate(); public abstract LocalDate asExclusiveEnd(); public abstract int toPixels(IDatesMapper datesMapper); public static class LocalDateBased extends GanttDate { private final LocalDate localDate; public LocalDateBased(LocalDate localDate) { Validate.notNull(localDate); this.localDate = localDate; } public LocalDate getLocalDate() { return localDate; } public <R> R byCases(ICases<R> cases) { return cases.on(this); } @Override public int compareTo(GanttDate o) { return o.byCases(new ICases<Integer>() { @Override public Integer on(LocalDateBased localDateBased) { return localDate.compareTo(localDateBased.localDate); } @Override public Integer on(CustomDate customType) { return -customType.compareToLocalDate(localDate); } }); } @Override public Date toDayRoundedDate() { return localDate.toDateTimeAtStartOfDay().toDate(); } @Override public LocalDate toLocalDate() { return localDate; } @Override public LocalDate asExclusiveEnd() { return localDate; } @Override public boolean isEqualsTo(GanttDate other) { return other.byCases(new ICases<Boolean>() { @Override public Boolean on(LocalDateBased localDateBased) { return localDate.equals(localDateBased.localDate); } @Override public Boolean on(CustomDate customType) { return false; } }); } @Override public int hashCode() { return localDate.hashCode(); } @Override public int toPixels(IDatesMapper datesMapper) { return datesMapper.toPixels(localDate); } } public static abstract class CustomDate extends GanttDate { public CustomDate() { } protected abstract boolean isEqualsToCustom(CustomDate customType); @Override protected boolean isEqualsTo(GanttDate other) { return other.byCases(new ICases<Boolean>() { @Override public Boolean on(LocalDateBased localDateBased) { return false; } @Override public Boolean on(CustomDate customType) { return isEqualsToCustom(customType); } }); } @Override public <R> R byCases(ICases<R> cases) { return cases.on(this); } @Override public int compareTo(GanttDate o) { return o.byCases(new ICases<Integer>() { @Override public Integer on(LocalDateBased localDateBased) { return compareToLocalDate(localDateBased.localDate); } @Override public Integer on(CustomDate customType) { return compareToCustom(customType); } }); } protected abstract int compareToCustom(CustomDate customType); protected abstract int compareToLocalDate(LocalDate localDate); } public boolean after(GanttDate other) { return compareTo(other) > 0; } }