Java tutorial
/* * Copyright (c) 2015, Kasra Faghihi, All rights reserved. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 3.0 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library. */ package com.offbynull.voip.kademlia.model; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import static java.util.Collections.emptyList; import java.util.HashSet; import java.util.Objects; import java.util.Set; import org.apache.commons.collections4.list.UnmodifiableList; import org.apache.commons.lang3.Validate; /** * Changes resulting from some operation performed on a collection that stores {@link Activity}s (includes nodes that were added, removed, * and updated). Essentially the same thing as a {@link NodeChangeSet} but also includes the times in which nodes were added, removed, or * updated. * <p> * Note that a single node can only be added, removed, or updated. It can never be a combination. * <p> * Class is immutable. * @author Kasra Faghihi */ public final class ActivityChangeSet { static final ActivityChangeSet NO_CHANGE = new ActivityChangeSet(emptyList(), emptyList(), emptyList()); private final UnmodifiableList<Activity> removed; private final UnmodifiableList<Activity> added; private final UnmodifiableList<Activity> updated; static ActivityChangeSet added(Activity... entries) { Validate.notNull(entries); Validate.noNullElements(entries); return added(Arrays.asList(entries)); } static ActivityChangeSet added(Collection<Activity> entries) { Validate.notNull(entries); Validate.noNullElements(entries); return new ActivityChangeSet(entries, emptyList(), emptyList()); } static ActivityChangeSet removed(Activity... entries) { Validate.notNull(entries); Validate.noNullElements(entries); return removed(Arrays.asList(entries)); } static ActivityChangeSet removed(Collection<Activity> entries) { Validate.notNull(entries); Validate.noNullElements(entries); return new ActivityChangeSet(emptyList(), entries, emptyList()); } static ActivityChangeSet updated(Activity... entries) { Validate.notNull(entries); Validate.noNullElements(entries); return updated(Arrays.asList(entries)); } static ActivityChangeSet updated(Collection<Activity> entries) { Validate.notNull(entries); Validate.noNullElements(entries); return new ActivityChangeSet(emptyList(), emptyList(), entries); } ActivityChangeSet(Collection<Activity> added, Collection<Activity> removed, Collection<Activity> updated) { Validate.notNull(removed); Validate.notNull(added); Validate.notNull(updated); Validate.noNullElements(removed); Validate.noNullElements(added); Validate.noNullElements(updated); // ensure that there aren't any duplicate ids Set<Id> tempSet = new HashSet<>(); removed.stream().map(x -> x.getNode().getId()).forEach(x -> tempSet.add(x)); added.stream().map(x -> x.getNode().getId()).forEach(x -> tempSet.add(x)); updated.stream().map(x -> x.getNode().getId()).forEach(x -> tempSet.add(x)); Validate.isTrue(tempSet.size() == added.size() + removed.size() + updated.size()); this.removed = (UnmodifiableList<Activity>) UnmodifiableList.unmodifiableList(new ArrayList<>(removed)); this.added = (UnmodifiableList<Activity>) UnmodifiableList.unmodifiableList(new ArrayList<>(added)); this.updated = (UnmodifiableList<Activity>) UnmodifiableList.unmodifiableList(new ArrayList<>(updated)); } /** * Get the list of nodes removed. * @return list (unmodifiable) of nodes removed */ public UnmodifiableList<Activity> viewRemoved() { return removed; } /** * Get the list of nodes added. * @return list (unmodifiable) of nodes added */ public UnmodifiableList<Activity> viewAdded() { return added; } /** * Get the list of nodes updated. * @return list (unmodifiable) of nodes updated */ public UnmodifiableList<Activity> viewUpdated() { return updated; } @Override public int hashCode() { int hash = 3; hash = 47 * hash + Objects.hashCode(this.removed); hash = 47 * hash + Objects.hashCode(this.added); hash = 47 * hash + Objects.hashCode(this.updated); return hash; } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final ActivityChangeSet other = (ActivityChangeSet) obj; if (!Objects.equals(this.removed, other.removed)) { return false; } if (!Objects.equals(this.added, other.added)) { return false; } if (!Objects.equals(this.updated, other.updated)) { return false; } return true; } @Override public String toString() { return "ActivityChangeSet{" + "removed=" + removed + ", added=" + added + ", updated=" + updated + '}'; } }