From 932513d8a1cba7150a8dccf4b19201308432d715 Mon Sep 17 00:00:00 2001
From: sk89q <the.sk89q@gmail.com>
Date: Wed, 9 Jul 2014 21:44:44 -0700
Subject: [PATCH] Add Transform.isIdentity().

---
 .../worldedit/math/transform/AffineTransform.java     |  1 +
 .../worldedit/math/transform/CombinedTransform.java   | 11 +++++++++++
 .../com/sk89q/worldedit/math/transform/Identity.java  |  5 +++++
 .../com/sk89q/worldedit/math/transform/Transform.java |  9 +++++++++
 4 files changed, 26 insertions(+)

diff --git a/src/main/java/com/sk89q/worldedit/math/transform/AffineTransform.java b/src/main/java/com/sk89q/worldedit/math/transform/AffineTransform.java
index eecdcc6cc..fe1709fa4 100644
--- a/src/main/java/com/sk89q/worldedit/math/transform/AffineTransform.java
+++ b/src/main/java/com/sk89q/worldedit/math/transform/AffineTransform.java
@@ -109,6 +109,7 @@ public class AffineTransform implements Transform {
     // ===================================================================
     // accessors
 
+    @Override
     public boolean isIdentity() {
         if (m00 != 1)
             return false;
diff --git a/src/main/java/com/sk89q/worldedit/math/transform/CombinedTransform.java b/src/main/java/com/sk89q/worldedit/math/transform/CombinedTransform.java
index 84b1a474b..eab410b99 100644
--- a/src/main/java/com/sk89q/worldedit/math/transform/CombinedTransform.java
+++ b/src/main/java/com/sk89q/worldedit/math/transform/CombinedTransform.java
@@ -54,6 +54,17 @@ public class CombinedTransform implements Transform {
         this(transforms.toArray(new Transform[checkNotNull(transforms).size()]));
     }
 
+    @Override
+    public boolean isIdentity() {
+        for (Transform transform : transforms) {
+            if (!transform.isIdentity()) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     @Override
     public Vector apply(Vector vector) {
         for (Transform transform : transforms) {
diff --git a/src/main/java/com/sk89q/worldedit/math/transform/Identity.java b/src/main/java/com/sk89q/worldedit/math/transform/Identity.java
index a5f22038d..cac70ba36 100644
--- a/src/main/java/com/sk89q/worldedit/math/transform/Identity.java
+++ b/src/main/java/com/sk89q/worldedit/math/transform/Identity.java
@@ -26,6 +26,11 @@ import com.sk89q.worldedit.Vector;
  */
 public class Identity implements Transform {
 
+    @Override
+    public boolean isIdentity() {
+        return true;
+    }
+
     @Override
     public Vector apply(Vector vector) {
         return vector;
diff --git a/src/main/java/com/sk89q/worldedit/math/transform/Transform.java b/src/main/java/com/sk89q/worldedit/math/transform/Transform.java
index cb3109879..b8df8bcbd 100644
--- a/src/main/java/com/sk89q/worldedit/math/transform/Transform.java
+++ b/src/main/java/com/sk89q/worldedit/math/transform/Transform.java
@@ -26,6 +26,15 @@ import com.sk89q.worldedit.Vector;
  */
 public interface Transform {
 
+    /**
+     * Return whether this transform is an identity.
+     *
+     * <p>If it is not known, then {@code false} must be returned.</p>
+     *
+     * @return true if identity
+     */
+    boolean isIdentity();
+
     /**
      * Returns the result of applying the function to the input.
      *