Add manager for state (uses Jackson to read/write JSON).

diff --git a/pom.xml b/pom.xml
index a6ca554..28d464d 100644 (file)
--- a/pom.xml
+++ b/pom.xml
@@ -55,5 +55,20 @@
                        <artifactId>jaxb</artifactId>
                        <version>2.1.9</version>
                </dependency>
+               <dependency>
+                       <groupId>com.fasterxml.jackson.core</groupId>
+                       <artifactId>jackson-core</artifactId>
+                       <version>2.1.2</version>
+               </dependency>
+               <dependency>
+                       <groupId>com.fasterxml.jackson.core</groupId>
+                       <artifactId>jackson-annotations</artifactId>
+                       <version>2.1.2</version>
+               </dependency>
+               <dependency>
+                       <groupId>com.fasterxml.jackson.core</groupId>
+                       <artifactId>jackson-databind</artifactId>
+                       <version>2.1.2</version>
+               </dependency>
        </dependencies>
 </project>

diff --git a/src/main/java/net/pterodactylus/reactor/states/StateManager.java b/src/main/java/net/pterodactylus/reactor/states/StateManager.java
new file mode 100644 (file)
index 0000000..cd0af2c
--- /dev/null
+++ b/src/main/java/net/pterodactylus/reactor/states/StateManager.java
@@ -0,0 +1,121 @@
+/*
+ * Reactor - 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.reactor.states;
+
+import java.io.File;
+import java.io.IOException;
+
+import net.pterodactylus.reactor.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 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 loadState(String reactionName) {
+               File stateFile = stateFile(reactionName);
+               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;
+       }
+
+       /**
+        * 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);
+                       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
+        * @return The file for the state
+        */
+       private File stateFile(String reactionName) {
+               return new File(directory, reactionName + ".json");
+       }
+
+}