Rename project to “Rhynodge.”

[rhynodge.git] / src / main / java / net / pterodactylus / rhynodge / states / StateManager.java

diff --git a/src/main/java/net/pterodactylus/rhynodge/states/StateManager.java b/src/main/java/net/pterodactylus/rhynodge/states/StateManager.java
new file mode 100644 (file)
index 0000000..19eccba
--- /dev/null
+++ b/src/main/java/net/pterodactylus/rhynodge/states/StateManager.java
@@ -0,0 +1,154 @@
+/*
+ * Rhynodge - StateManager.java - Copyright © 2013 David Roden
+ *
+ * This program 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.
+ *
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.rhynodge.states;
+
+import java.io.File;
+import java.io.IOException;
+
+import net.pterodactylus.rhynodge.State;
+
+import org.apache.log4j.Logger;
+
+import com.fasterxml.jackson.core.JsonGenerationException;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * Loads and saves {@link State}s.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class StateManager {
+
+       /** The logger. */
+       private static final Logger logger = Logger.getLogger(StateManager.class);
+
+       /** Jackson object mapper. */
+       private final ObjectMapper objectMapper = new ObjectMapper();
+
+       /** The directory in which to store states. */
+       private final String directory;
+
+       /**
+        * Creates a new state manager. The given directory is assumed to exist.
+        *
+        * @param directory
+        *            The directory to store states in
+        */
+       public StateManager(String directory) {
+               this.directory = directory;
+       }
+
+       //
+       // ACTIONS
+       //
+
+       /**
+        * Loads the last state with the given name.
+        *
+        * @param reactionName
+        *            The name of the reaction
+        * @return The loaded state, or {@code null} if the state could not be
+        *         loaded
+        */
+       public State loadLastState(String reactionName) {
+               return loadLastState(reactionName, false);
+       }
+
+       /**
+        * Loads the last state with the given name.
+        *
+        * @param reactionName
+        *            The name of the reaction
+        * @return The loaded state, or {@code null} if the state could not be
+        *         loaded
+        */
+       public State loadLastSuccessfulState(String reactionName) {
+               return loadLastState(reactionName, true);
+       }
+
+       /**
+        * Saves the given state under the given name.
+        *
+        * @param reactionName
+        *            The name of the reaction
+        * @param state
+        *            The state to save
+        */
+       public void saveState(String reactionName, State state) {
+               try {
+                       File stateFile = stateFile(reactionName, "last");
+                       objectMapper.writeValue(stateFile, state);
+                       if (state.success()) {
+                               stateFile = stateFile(reactionName, "success");
+                               objectMapper.writeValue(stateFile, state);
+                       }
+               } catch (JsonGenerationException jge1) {
+                       logger.warn(String.format("State for Reaction “%s” could not be generated.", reactionName), jge1);
+               } catch (JsonMappingException jme1) {
+                       logger.warn(String.format("State for Reaction “%s” could not be generated.", reactionName), jme1);
+               } catch (IOException ioe1) {
+                       logger.warn(String.format("State for Reaction “%s” could not be written.", reactionName));
+               }
+       }
+
+       //
+       // PRIVATE METHODS
+       //
+
+       /**
+        * Returns the file for the state with the given name.
+        *
+        * @param reactionName
+        *            The name of the reaction
+        * @param suffix
+        *            An additional suffix (may be {@code null}
+        * @return The file for the state
+        */
+       private File stateFile(String reactionName, String suffix) {
+               return new File(directory, reactionName + ((suffix != null) ? "." + suffix : "") + ".json");
+       }
+
+       /**
+        * Load the given state for the reaction with the given name.
+        *
+        * @param reactionName
+        *            The name of the reaction
+        * @param successful
+        *            {@code true} to load the last successful state, {@code false}
+        *            to load the last state
+        * @return The loaded state, or {@code null} if the state could not be
+        *         loaded
+        */
+       private State loadLastState(String reactionName, boolean successful) {
+               File stateFile = stateFile(reactionName, successful ? "success" : "last");
+               try {
+                       State state = objectMapper.readValue(stateFile, AbstractState.class);
+                       return state;
+               } catch (JsonParseException jpe1) {
+                       logger.warn(String.format("State for Reaction “%s” could not be parsed.", reactionName), jpe1);
+               } catch (JsonMappingException jme1) {
+                       logger.warn(String.format("State for Reaction “%s” could not be parsed.", reactionName), jme1);
+               } catch (IOException ioe1) {
+                       logger.info(String.format("State for Reaction “%s” could not be found.", reactionName));
+               }
+               return null;
+       }
+
+}