Implement suggestions from PR comments

Core/src/main/java/com/plotsquared/core/command/Auto.java

@@ -94,7 +94,7 @@ public class Auto extends SubCommand {
         if (diff - sizeX * sizeZ < 0) {
             try (final MetaDataAccess<Integer> metaDataAccess = player.accessPersistentMetaData(
                 PlayerMetaDataKeys.PERSISTENT_GRANTED_PLOTS)) {
-                if (metaDataAccess.has()) {
+                if (metaDataAccess.isPresent()) {
                     int grantedPlots = metaDataAccess.get().orElse(0);
                     if (diff < 0 && grantedPlots < sizeX * sizeZ) {
                         MainUtil.sendMessage(player, Captions.CANT_CLAIM_MORE_PLOTS);

Core/src/main/java/com/plotsquared/core/command/Claim.java

@@ -92,7 +92,7 @@ public class Claim extends SubCommand {
         try (final MetaDataAccess<Integer> metaDataAccess = player.accessPersistentMetaData(PlayerMetaDataKeys.PERSISTENT_GRANTED_PLOTS)) {
             int grants = 0;
             if (currentPlots >= player.getAllowedPlots() && !force) {
-                if (metaDataAccess.has()) {
+                if (metaDataAccess.isPresent()) {
                     grants = metaDataAccess.get().orElse(0);
                     if (grants <= 0) {
                         metaDataAccess.remove();

Core/src/main/java/com/plotsquared/core/player/MetaDataAccess.java

@@ -34,7 +34,6 @@ import java.util.Optional;
 /**
  * Access to player meta data
  *
- * @param <P> Player type
  * @param <T> Meta data type
  */
 public abstract class MetaDataAccess<T> implements AutoCloseable {
@@ -42,6 +41,7 @@ public abstract class MetaDataAccess<T> implements AutoCloseable {
     private final PlotPlayer<?> player;
     private final MetaDataKey<T> metaDataKey;
     private final LockRepository.LockAccess lockAccess;
+    private boolean closed = false;
 
     MetaDataAccess(@Nonnull final PlotPlayer<?> player, @Nonnull final MetaDataKey<T> metaDataKey,
         @Nonnull final LockRepository.LockAccess lockAccess) {
@@ -56,12 +56,12 @@ public abstract class MetaDataAccess<T> implements AutoCloseable {
      * @return {@code true} if player has meta data with this key, or
      * {@code false}
      */
-    public abstract boolean has();
+    public abstract boolean isPresent();
 
     /**
      * Remove the stored value meta data
      *
-     * @return Old value, or {@link null}
+     * @return Old value, or {@code null}
      */
     @Nullable public abstract T remove();
 
@@ -81,6 +81,7 @@ public abstract class MetaDataAccess<T> implements AutoCloseable {
 
     @Override public final void close() {
         this.lockAccess.close();
+        this.closed = true;
     }
 
     /**
@@ -101,4 +102,28 @@ public abstract class MetaDataAccess<T> implements AutoCloseable {
         return this.metaDataKey;
     }
 
+    /**
+     * Check whether or not the meta data access has been closed.
+     * After being closed, all attempts to access the meta data
+     * through the instance, will lead to {@link IllegalAccessException}
+     * being thrown
+     *
+     * @return {@code true} if the access has been closed
+     */
+    public boolean isClosed() {
+        return this.closed;
+    }
+
+    protected void checkClosed() {
+        if (this.closed) {
+            sneakyThrow(new IllegalAccessException("The meta data access instance has been closed"));
+        }
+    }
+
+    @SuppressWarnings("ALL")
+    private static <E extends Throwable> void sneakyThrow(final Throwable e) throws E {
+        throw (E) e;
+    }
+
+
 }

Core/src/main/java/com/plotsquared/core/player/PersistentMetaDataAccess.java

@@ -39,11 +39,13 @@ final class PersistentMetaDataAccess<T> extends MetaDataAccess<T> {
         super(player, metaDataKey, lockAccess);
     }
 
-    @Override public boolean has() {
+    @Override public boolean isPresent() {
+        this.checkClosed();
         return this.getPlayer().hasPersistentMeta(getMetaDataKey().toString());
     }
 
     @Override @Nullable public T remove() {
+        this.checkClosed();
         final Object old = this.getPlayer().removePersistentMeta(this.getMetaDataKey().toString());
         if (old == null) {
             return null;
@@ -52,10 +54,12 @@ final class PersistentMetaDataAccess<T> extends MetaDataAccess<T> {
     }
 
     @Override public void set(@Nonnull T value) {
+        this.checkClosed();
         this.getPlayer().setPersistentMeta(this.getMetaDataKey(), value);
     }
 
     @Nonnull @Override public Optional<T> get() {
+        this.checkClosed();
         return Optional.ofNullable(this.getPlayer().getPersistentMeta(this.getMetaDataKey()));
     }
 

Core/src/main/java/com/plotsquared/core/player/TemporaryMetaDataAccess.java

@@ -39,11 +39,13 @@ final class TemporaryMetaDataAccess<T> extends MetaDataAccess<T> {
         super(player, metaDataKey, lockAccess);
     }
 
-    @Override public boolean has() {
+    @Override public boolean isPresent() {
+        this.checkClosed();
         return this.getPlayer().getMeta(this.getMetaDataKey().toString()) != null;
     }
 
     @Override @Nullable public T remove() {
+        this.checkClosed();
         final Object old = getPlayer().deleteMeta(this.getMetaDataKey().toString());
         if (old == null) {
             return null;
@@ -52,10 +54,12 @@ final class TemporaryMetaDataAccess<T> extends MetaDataAccess<T> {
     }
 
     @Override public void set(@Nonnull T value) {
+        this.checkClosed();
         this.getPlayer().setMeta(this.getMetaDataKey().toString(), null);
     }
 
     @Nonnull @Override public Optional<T> get() {
+        this.checkClosed();
         return Optional.ofNullable(this.getPlayer().getMeta(this.getMetaDataKey().toString()));
     }
 

Core/src/main/java/com/plotsquared/core/plot/expiration/ExpireManager.java

@@ -142,7 +142,7 @@ public class ExpireManager {
     public void confirmExpiry(final PlotPlayer<?> pp) {
         try (final MetaDataAccess<Boolean> metaDataAccess = pp.accessTemporaryMetaData(
             PlayerMetaDataKeys.TEMPORARY_IGNORE_EXPIRE_TASK)) {
-            if (metaDataAccess.has()) {
+            if (metaDataAccess.isPresent()) {
                 return;
             }
             if (plotsToDelete != null && !plotsToDelete.isEmpty() && pp.hasPermission("plots.admin.command.autoclear")) {