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Semester 1/Programming 1/Java/examples/projects/chapter07/brain/Cell.java

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+import java.util.*;
+
+/**
+ * A cell in a 2D cellular automaton.
+ * The cell has multiple possible states.
+ * This is an implementation of the rules for Brian's Brain.
+ * @see https://en.wikipedia.org/wiki/Brian%27s_Brain
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version  2016.02.29
+ */
+public class Cell
+{
+    // The possible states.
+    public static final int ALIVE = 0, DEAD = 1, DYING = 2;
+    // The number of possible states.
+    public static final int NUM_STATES = 3;
+
+    // The cell's state.
+    private int state;
+    // The cell's neighbors.
+    private Cell[] neighbors;
+
+    /**
+     * Set the initial state to be DEAD.
+     */
+    public Cell()
+    {
+        this(DEAD);
+    }
+    
+    /**
+     * Set the initial state.
+     * @param initialState The initial state
+     */
+    public Cell(int initialState)
+    {
+        state = initialState;
+        neighbors = new Cell[0];
+    }
+    
+    /**
+     * Determine this cell's next state, based on the
+     * state of its neighbors.
+     * This is an implementation of the rules for Brian's Brain.
+     * @return The next state.
+     */
+    public int getNextState()
+    {
+        if(state == DEAD) {
+            // Count the number of neighbors that are alive.
+            int aliveCount = 0;
+            for(Cell n : neighbors) {
+                if(n.getState() == ALIVE) {
+                    aliveCount++;
+                }
+            }
+            return aliveCount == 2 ? ALIVE : DEAD;
+        }
+        else if(state == DYING) {
+            return DEAD;
+        }
+        else {
+            return DYING;
+        }
+    }
+    
+    /**
+     * Receive the list of neighboring cells and take
+     * a copy.
+     * @param neighborList Neighboring cells.
+     */
+    public void setNeighbors(ArrayList<Cell> neighborList)
+    {
+        neighbors = new Cell[neighborList.size()];
+        neighborList.toArray(neighbors);
+    }
+
+    /**
+     * Get the state of this cell.
+     * @return The state.
+     */
+    public int getState()
+    {
+        return state;
+    }
+    
+    /**
+     * Set the state of this cell.
+     * @param The state.
+     */
+    public void setState(int state)
+    {
+        this.state = state;
+    }   
+    
+}