2 * Rhynodge - State.java - Copyright © 2013 David Roden
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 package net.pterodactylus.rhynodge;
20 import javax.annotation.Nonnull;
22 import net.pterodactylus.rhynodge.output.Output;
25 * Defines the current state of a system.
27 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
29 public interface State {
32 * Returns the time when this state was retrieved.
34 * @return The time when this state was retrieved (in millseconds since Jan
40 * Whether the state was successfully retrieved. This method should only
41 * return {@code true} if a meaningful result could be retrieved; if e. g. a
42 * service is currently not reachable, this method should return false
43 * instead of emulating success by using empty lists or similar constructs.
45 * @return {@code true} if the state could be retrieved successfully,
46 * {@code false} otherwise
51 * Returns whether this state triggers a change notification. This can
52 * only return {@code true} if this state is the result of a
53 * {@link Merger} merging two states.
55 * @return {@code true} if this state triggers a change notification,
56 * {@code false} otherwise
61 * Sets whether this state will trigger a notification.
68 * Returns the number of consecutive failures. This method only returns a
69 * meaningful number iff {@link #success()} returns {@code false}. If
70 * {@link #success()} returns {@code false} for the first time after
71 * returning {@code true} and this method is called after {@link #success()}
72 * it will return {@code 1}.
74 * @return The number of consecutive failures
79 * Sets the fail count of this state.
82 * The fail count of this state
84 void setFailCount(int failCount);
87 * If {@link #success()} returns {@code false}, this method may return a
88 * {@link Throwable} to give some details for the reason why retrieving the
89 * state was not possible. For example, network-based {@link Query}s might
90 * return any exception that were encountered while communicating with the
93 * @return An exception that occured, may be {@code null} in case an
94 * exception can not be meaningfully returned
96 Throwable exception();
99 Output output(Reaction reaction);