Add API class / fix #23

src/main/java/com/github/kory33/signvote/api/SignVoteAPI.java

@@ -0,0 +1,38 @@
+package com.github.kory33.signvote.api;
+
+import com.github.kory33.signvote.core.SignVote;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockState;
+import org.bukkit.block.Sign;
+
+/**
+ * An API of SignVote which may be openly accessed by addons.
+ * <p>
+ * Please note that you should only access the internals of SignVote plugin
+ * only if the desired functionality is not provided by this class or its subclasses.
+ * <p>
+ * Internal access may damage the data structure of SignVote plugin, hence
+ * manipulating SignVote's data should be done with a certain care.
+ */
+public class SignVoteAPI {
+    private final SignVote plugin;
+
+    public SignVoteAPI(SignVote plugin) {
+        this.plugin = plugin;
+    }
+
+    /**
+     * Checks if the given block is a SignVote's vote-point
+     * @param block target block
+     * @return true if the sign is a vote-point
+     */
+    public boolean isSignVoteSign(Block block) {
+        BlockState blockState = block.getState();
+        if (!(blockState instanceof Sign)) {
+            return false;
+        }
+
+        Sign sign = (Sign) blockState;
+        return this.plugin.getVoteSessionManager().getVoteSession(sign).isPresent();
+    }
+}

src/main/java/com/github/kory33/signvote/core/SignVote.java

@@ -5,6 +5,7 @@
 import java.util.logging.Level;
 
 import com.github.kory33.chatgui.command.RunnableInvoker;
+import com.github.kory33.signvote.api.SignVoteAPI;
 import org.bstats.Metrics;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.event.HandlerList;
@@ -34,6 +35,7 @@ public class SignVote extends GithubUpdateNotifyPlugin {
     @Getter private RunnableInvoker runnableInvoker;
     @Getter private PlayerInteractiveInterfaceManager interfaceManager;
     @Getter private PlayerChatInterceptor chatInterceptor;
+    @Getter private SignVoteAPI API;
 
     private boolean isEnabled = false;
 
@@ -110,6 +112,8 @@ public void onEnable() {
 
         this.enableMetrics();
         this.isEnabled = true;
+
+        this.API = new SignVoteAPI(this);
     }
 
     @Override

src/main/java/com/github/kory33/signvote/listeners/SignListener.java

@@ -1,5 +1,7 @@
 package com.github.kory33.signvote.listeners;
 
+import com.github.kory33.signvote.utils.BlockUtil;
+import org.bukkit.block.Block;
 import org.bukkit.block.BlockState;
 import org.bukkit.block.Sign;
 import org.bukkit.event.EventHandler;
@@ -16,15 +18,21 @@
 import com.github.kory33.signvote.manager.VoteSessionManager;
 import com.github.kory33.signvote.model.VotePoint;
 import com.github.kory33.signvote.session.VoteSession;
+import org.bukkit.material.MaterialData;
+
+import java.util.Optional;
+import java.util.Set;
 
 /**
  * A Listener implementation which listens to player's interaction with sign.
  */
 public class SignListener implements Listener {
     private final JSONConfiguration messageConfig;
     private final VoteSessionManager voteSessionManager;
+    private final SignVote plugin;
 
     public SignListener(SignVote plugin) {
+        this.plugin = plugin;
         plugin.getServer().getPluginManager().registerEvents(this, plugin);
 
         this.messageConfig = plugin.getMessagesConfiguration();
@@ -86,17 +94,48 @@ public void onVotePointBreak(BlockBreakEvent event) {
         }
 
         Sign sign = (Sign)state;
-        VotePoint votePoint = this.voteSessionManager.getVotePoint(sign);
-
-        if (votePoint == null) {
+        Optional<VoteSession> optionalSession = this.voteSessionManager.getVoteSession(sign);
+        if (!optionalSession.isPresent()) {
             return;
         }
 
-        String sessionName = voteSessionManager.getVoteSession(sign).getName();
-        String votepointName = votePoint.getName();
+        VoteSession session = optionalSession.get();
+
+        String sessionName = session.getName();
+        String votepointName = session.getVotePoint(sign).getName();
 
         event.setCancelled(true);
         event.getPlayer().sendMessage(messageConfig.getFormatted(MessageConfigNodes.F_VOTEPOINT_BREAK,
                 sessionName, votepointName));
     }
+
+    @EventHandler
+    public void onVotePointBaseBlockBreak(BlockBreakEvent event) {
+        Block brokenBlock = event.getBlock();
+
+        Set<Block> attachedVotePoints = BlockUtil.getBlocksAdjacentTo(brokenBlock);
+        attachedVotePoints.removeIf(block -> {
+            // ignore if the block is not a sign
+            MaterialData state = block.getState().getData();
+            if (!(state instanceof org.bukkit.material.Sign)) {
+                return true;
+            }
+
+            // ignore if the sign is not attached to the broken block
+            org.bukkit.material.Sign signMaterial = (org.bukkit.material.Sign) state;
+            Block attachedBlock = block.getRelative(signMaterial.getAttachedFace());
+            if (!attachedBlock.equals(brokenBlock)) {
+                return true;
+            }
+
+            // ignore if the sign is not a SignVote's vote-point
+            return !this.plugin.getAPI().isSignVoteSign(block);
+        });
+
+        if (attachedVotePoints.isEmpty()) {
+            return;
+        }
+
+        event.setCancelled(true);
+    }
 }