Add Entity visitor and function interfaces.

src/main/java/com/sk89q/worldedit/function/EntityFunction.java

@@ -0,0 +1,39 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.function;
+
+import com.sk89q.worldedit.WorldEditException;
+import com.sk89q.worldedit.entity.Entity;
+
+/**
+ * Applies a function to entities.
+ */
+public interface EntityFunction {
+
+    /**
+     * Apply the function to the entity.
+     *
+     * @param entity the entity
+     * @return true if something was changed
+     * @throws WorldEditException thrown on an error
+     */
+    public boolean apply(Entity entity) throws WorldEditException;
+
+}

src/main/java/com/sk89q/worldedit/function/visitor/EntityVisitor.java

@@ -0,0 +1,78 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.function.visitor;
+
+import com.sk89q.worldedit.WorldEditException;
+import com.sk89q.worldedit.entity.Entity;
+import com.sk89q.worldedit.function.EntityFunction;
+import com.sk89q.worldedit.function.operation.Operation;
+import com.sk89q.worldedit.function.operation.RunContext;
+
+import java.util.Iterator;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Visits entities as provided by an {@code Iterator}.
+ */
+public class EntityVisitor implements Operation {
+
+    private final Iterator<Entity> iterator;
+    private final EntityFunction function;
+    private int affected = 0;
+
+    /**
+     * Create a new instance.
+     *
+     * @param iterator the iterator
+     * @param function the function
+     */
+    public EntityVisitor(Iterator<Entity> iterator, EntityFunction function) {
+        checkNotNull(iterator);
+        checkNotNull(function);
+        this.iterator = iterator;
+        this.function = function;
+    }
+
+    /**
+     * Get the number of affected objects.
+     *
+     * @return the number of affected
+     */
+    public int getAffected() {
+        return affected;
+    }
+
+    @Override
+    public Operation resume(RunContext run) throws WorldEditException {
+        while (iterator.hasNext()) {
+            if (function.apply(iterator.next())) {
+                affected++;
+            }
+        }
+
+        return null;
+    }
+
+    @Override
+    public void cancel() {
+    }
+
+}