Implement Cancellable in ClaimModifiedEvent (#942)

- If canceled, GP stops processing the resize command (no error printed or potential overlapping claim displayed)

src/main/java/me/ryanhamshire/GriefPrevention/Claim.java

@@ -250,6 +250,24 @@ public class Claim
         this(lesserBoundaryCorner, greaterBoundaryCorner, ownerID, builderIDs, containerIDs, accessorIDs, managerIDs, false, id);
     }
 
+    //produces a copy of a claim.
+    public Claim(Claim claim) {
+        this.modifiedDate = claim.modifiedDate;
+        this.lesserBoundaryCorner = claim.greaterBoundaryCorner.clone();
+        this.greaterBoundaryCorner = claim.greaterBoundaryCorner.clone();
+        this.id = claim.id;
+        this.ownerID = claim.ownerID;
+        this.managers = new ArrayList<>(claim.managers);
+        this.playerIDToClaimPermissionMap = new HashMap<>(claim.playerIDToClaimPermissionMap);
+        this.inDataStore = false; //since it's a copy of a claim, not in datastore!
+        this.areExplosivesAllowed = claim.areExplosivesAllowed;
+        this.parent = claim.parent;
+        this.inheritNothing = claim.inheritNothing;
+        this.children = new ArrayList<>(claim.children);
+        this.siegeData = claim.siegeData;
+        this.doorsOpen = claim.doorsOpen;
+    }
+
     //measurements.  all measurements are in blocks
     public int getArea()
     {

src/main/java/me/ryanhamshire/GriefPrevention/DataStore.java

@@ -1051,8 +1051,6 @@ public abstract class DataStore
 
         //save changes
         this.saveClaim(claim);
-        ClaimModifiedEvent event = new ClaimModifiedEvent(claim, null);
-        Bukkit.getPluginManager().callEvent(event);
     }
 
     //starts a siege on a claim
@@ -1314,8 +1312,6 @@ public abstract class DataStore
 
             //save those changes
             this.saveClaim(result.claim);
-            ClaimModifiedEvent event = new ClaimModifiedEvent(result.claim, resizingPlayer);
-            Bukkit.getPluginManager().callEvent(event);
         }
 
         return result;
@@ -1362,18 +1358,24 @@ public abstract class DataStore
             }
         }
 
+        Claim oldClaim = playerData.claimResizing;
+        Claim newClaim = new Claim(oldClaim);
+        World world = newClaim.getLesserBoundaryCorner().getWorld();
+        newClaim.lesserBoundaryCorner = new Location(world, newx1, newy1, newz1);
+        newClaim.greaterBoundaryCorner = new Location(world, newx2, newy2, newz2);
+
+        //call event here to check if it has been cancelled
+        ClaimModifiedEvent event = new ClaimModifiedEvent(oldClaim, newClaim, player);
+        Bukkit.getPluginManager().callEvent(event);
+
+        //return here if event is cancelled
+        if (event.isCancelled()) return;
+
         //special rule for making a top-level claim smaller.  to check this, verifying the old claim's corners are inside the new claim's boundaries.
         //rule: in any mode, shrinking a claim removes any surface fluids
-        Claim oldClaim = playerData.claimResizing;
         boolean smaller = false;
         if (oldClaim.parent == null)
         {
-            //temporary claim instance, just for checking contains()
-            Claim newClaim = new Claim(
-                    new Location(oldClaim.getLesserBoundaryCorner().getWorld(), newx1, newy1, newz1),
-                    new Location(oldClaim.getLesserBoundaryCorner().getWorld(), newx2, newy2, newz2),
-                    null, new ArrayList<String>(), new ArrayList<String>(), new ArrayList<String>(), new ArrayList<String>(), null);
-
             //if the new claim is smaller
             if (!newClaim.contains(oldClaim.getLesserBoundaryCorner(), true, false) || !newClaim.contains(oldClaim.getGreaterBoundaryCorner(), true, false))
             {

src/main/java/me/ryanhamshire/GriefPrevention/events/ClaimModifiedEvent.java

@@ -3,6 +3,7 @@ package me.ryanhamshire.GriefPrevention.events;
 
 import me.ryanhamshire.GriefPrevention.Claim;
 import org.bukkit.command.CommandSender;
+import org.bukkit.event.Cancellable;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 
@@ -11,7 +12,7 @@ import org.bukkit.event.HandlerList;
  * a claim has changed. The CommandSender can be null in the event that the modification is called by the plugin itself.
  * Created by Narimm on 5/08/2018.
  */
-public class ClaimModifiedEvent extends Event
+public class ClaimModifiedEvent extends Event implements Cancellable
 {
 
     private static final HandlerList handlers = new HandlerList();
@@ -21,12 +22,15 @@ public class ClaimModifiedEvent extends Event
         return handlers;
     }
 
-    private final Claim claim;
+    private final Claim from;
+    private final Claim to;
     private CommandSender modifier;
+    private boolean cancelled;
 
-    public ClaimModifiedEvent(Claim claim, CommandSender modifier)
+    public ClaimModifiedEvent(Claim from, Claim to, CommandSender modifier)
     {
-        this.claim = claim;
+        this.from = from;
+        this.to = to;
         this.modifier = modifier;
     }
 
@@ -40,10 +44,22 @@ public class ClaimModifiedEvent extends Event
      * The claim
      *
      * @return the claim
+     * @deprecated Use the {@link #getTo() getTo} method.
      */
+    @Deprecated
     public Claim getClaim()
     {
-        return claim;
+        return to;
+    }
+
+    public Claim getFrom()
+    {
+        return from;
+    }
+
+    public Claim getTo()
+    {
+        return to;
     }
 
     /**
@@ -55,4 +71,16 @@ public class ClaimModifiedEvent extends Event
     {
         return modifier;
     }
+
+    @Override
+    public boolean isCancelled()
+    {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancelled)
+    {
+        this.cancelled = cancelled;
+    }
 }