Refactor engine, use Optionals in the state manager.

[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
index 19eccba..35125bb 100644 (file)
--- a/src/main/java/net/pterodactylus/rhynodge/states/StateManager.java
+++ b/src/main/java/net/pterodactylus/rhynodge/states/StateManager.java
@@ -17,11 +17,15 @@
 
 package net.pterodactylus.rhynodge.states;
 
+import static com.google.common.base.Optional.absent;
+import static com.google.common.base.Optional.fromNullable;
+
 import java.io.File;
 import java.io.IOException;
 
 import net.pterodactylus.rhynodge.State;
 
+import com.google.common.base.Optional;
 import org.apache.log4j.Logger;
 
 import com.fasterxml.jackson.core.JsonGenerationException;
@@ -64,10 +68,10 @@ public class StateManager {
         *
         * @param reactionName
         *            The name of the reaction
-        * @return The loaded state, or {@code null} if the state could not be
+        * @return The loaded state, or {@link Optional#absent()} if the state could not be
         *         loaded
         */
-       public State loadLastState(String reactionName) {
+       public Optional<State> loadLastState(String reactionName) {
                return loadLastState(reactionName, false);
        }
 
@@ -76,10 +80,10 @@ public class StateManager {
         *
         * @param reactionName
         *            The name of the reaction
-        * @return The loaded state, or {@code null} if the state could not be
+        * @return The loaded state, or {@link Optional#absent()} if the state could not be
         *         loaded
         */
-       public State loadLastSuccessfulState(String reactionName) {
+       public Optional<State> loadLastSuccessfulState(String reactionName) {
                return loadLastState(reactionName, true);
        }
 
@@ -133,14 +137,14 @@ public class StateManager {
         * @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
+        * @return The loaded state, or {@link Optional#absent()} if the state could not be
         *         loaded
         */
-       private State loadLastState(String reactionName, boolean successful) {
+       private Optional<State> loadLastState(String reactionName, boolean successful) {
                File stateFile = stateFile(reactionName, successful ? "success" : "last");
                try {
                        State state = objectMapper.readValue(stateFile, AbstractState.class);
-                       return state;
+                       return fromNullable(state);
                } catch (JsonParseException jpe1) {
                        logger.warn(String.format("State for Reaction “%s” could not be parsed.", reactionName), jpe1);
                } catch (JsonMappingException jme1) {
@@ -148,7 +152,7 @@ public class StateManager {
                } catch (IOException ioe1) {
                        logger.info(String.format("State for Reaction “%s” could not be found.", reactionName));
                }
-               return null;
+               return absent();
        }
 
 }