From 6781889388164d34749fb6eb05d3b4a5ed74aa1d Mon Sep 17 00:00:00 2001
From: pacien
Date: Mon, 8 Jan 2018 14:11:11 +0100
Subject: Make Board immutable

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 src/main/java/fr/umlv/java/wallj/board/Board.java  | 54 ++++++++++++++++------
 src/main/java/fr/umlv/java/wallj/utils/Matrix.java | 28 +++++++++++
 2 files changed, 67 insertions(+), 15 deletions(-)
 create mode 100644 src/main/java/fr/umlv/java/wallj/utils/Matrix.java

(limited to 'src/main/java/fr/umlv')

diff --git a/src/main/java/fr/umlv/java/wallj/board/Board.java b/src/main/java/fr/umlv/java/wallj/board/Board.java
index ebe1a7e..dfcec88 100644
--- a/src/main/java/fr/umlv/java/wallj/board/Board.java
+++ b/src/main/java/fr/umlv/java/wallj/board/Board.java
@@ -1,16 +1,51 @@
 package fr.umlv.java.wallj.board;
 
 import fr.umlv.java.wallj.model.BlockType;
+import fr.umlv.java.wallj.utils.Matrix;
 
 /**
- * A mutable BlockType matrix.
+ * An immutable BlockType matrix.
  */
 public final class Board {
 
+  /**
+   * Board Builder
+   */
+  public static final class Builder {
+    private final BlockType[][] map;
+
+    /**
+     * @param width  width in tiles
+     * @param height height in tiles
+     */
+    public Builder(int width, int height) {
+      this.map = new BlockType[width][height];
+    }
+
+    /**
+     * @param pos  the tile position vector
+     * @param type the BlockType to set
+     * @return the Builder
+     */
+    public Builder setBlockTypeAt(TileVec2 pos, BlockType type) {
+      map[pos.getCol()][pos.getRow()] = type;
+      return this;
+    }
+
+    /**
+     * @return the immutable Board
+     */
+    public Board build() {
+      return new Board(map);
+    }
+  }
+
   private final BlockType[][] map;
 
-  public Board(int width, int height) {
-    map = new BlockType[width][height];
+  private Board(BlockType[][] map) {
+    int w = Matrix.getWidth(map), h = Matrix.getHeight(map);
+    this.map = new BlockType[w][h];
+    for (int row = 0; row < w; ++row) System.arraycopy(map[row], 0, this.map[row], 0, h);
   }
 
   /**
@@ -21,22 +56,11 @@ public final class Board {
     return map[pos.getCol()][pos.getRow()];
   }
 
-  /**
-   * @param pos  the tile position vector
-   * @param type the BlockType to set
-   * @return the overwritten element
-   */
-  public BlockType setBlockTypeAt(TileVec2 pos, BlockType type) {
-    BlockType old = map[pos.getCol()][pos.getRow()];
-    map[pos.getCol()][pos.getRow()] = type;
-    return old;
-  }
-
   /**
    * @return the dimension of the Board
    */
   public TileVec2 getDim() {
-    return TileVec2.of(map.length, map.length > 0 ? map[0].length : 0);
+    return TileVec2.of(Matrix.getWidth(map), Matrix.getHeight(map));
   }
 
 }
diff --git a/src/main/java/fr/umlv/java/wallj/utils/Matrix.java b/src/main/java/fr/umlv/java/wallj/utils/Matrix.java
new file mode 100644
index 0000000..e23cb2a
--- /dev/null
+++ b/src/main/java/fr/umlv/java/wallj/utils/Matrix.java
@@ -0,0 +1,28 @@
+package fr.umlv.java.wallj.utils;
+
+/**
+ * Utility functions for two dimension arrays.
+ */
+public final class Matrix {
+
+  /**
+   * @param m the matrix
+   * @return the width of the matrix (0 if null)
+   */
+  public static int getWidth(Object[][] m) {
+    return m != null && m.length > 0 ? m[0].length : 0;
+  }
+
+  /**
+   * @param m the matrix
+   * @return the height of the matrix (0 if null)
+   */
+  public static int getHeight(Object[][] m) {
+    return m != null ? m.length : 0;
+  }
+
+  private Matrix() {
+    // static class
+  }
+
+}
-- 
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