Documentation

docs/hw1/SimpleVisitor.java

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+import java.lang.*;
+
+abstract class TreeNode {
+	public int key;
+	public TreeNode leftchild;
+	public TreeNode rightchild;
+
+	public TreeNode(int k, TreeNode left, TreeNode right) {
+		key = k;
+		leftchild = left;
+		rightchild = right;
+	}
+}
+
+class BlueNode extends TreeNode {
+	public BlueNode(int k, TreeNode left, TreeNode right) { super(k, left, right); }
+}
+
+class GreenNode extends TreeNode {
+	public GreenNode(int k, TreeNode left, TreeNode right) { super(k, left, right); }
+}
+
+class Visitor {
+	public void visit(TreeNode node) {
+		System.out.print(node.key + ": ");
+
+		if (node instanceof BlueNode)
+			System.out.println("Blue");
+		else if (node instanceof GreenNode)
+			System.out.println("Green");
+
+		if (node.leftchild != null) visit(node.leftchild);
+		if (node.rightchild != null) visit(node.rightchild);
+	}
+}
+
+public class SimpleVisitor {
+	public static void main(String [] args) {
+		TreeNode root = new BlueNode(1,
+				new GreenNode(21,
+						new BlueNode(31, null, null),
+						new GreenNode(32, null, null)),
+				new GreenNode(22,
+						new BlueNode(33, null, null),
+						new GreenNode(34, null, null)));
+		Visitor v = new Visitor();
+		v.visit(root);
+	}
+}

docs/hw1/VisitorPattern.java

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+import java.lang.*;
+
+abstract class TreeNode {
+	public int key;
+	public TreeNode leftchild;
+	public TreeNode rightchild;
+
+	public TreeNode(int k, TreeNode left, TreeNode right) {
+		key = k;
+		leftchild = left;
+		rightchild = right;
+	}
+
+	public abstract void accept(Visitor v);
+}
+
+class BlueNode extends TreeNode {
+	public BlueNode(int k, TreeNode left, TreeNode right) { super(k, left, right); }
+
+	public void accept(Visitor v) {
+		v.blueNode(this);
+	}
+}
+
+class GreenNode extends TreeNode {
+	public GreenNode(int k, TreeNode left, TreeNode right) { super(k, left, right); }
+
+	public void accept(Visitor v) {
+		v.greenNode(this);
+	}
+}
+
+class Visitor {
+	public void blueNode(BlueNode node) {
+		System.out.print(node.key + ": ");
+		System.out.println("Blue");
+
+		if (node.leftchild != null) node.leftchild.accept(this);
+		if (node.rightchild != null) node.rightchild.accept(this);
+	}
+
+	public void greenNode(GreenNode node) {
+		System.out.print(node.key + ": ");
+		System.out.println("Green");
+
+		if (node.leftchild != null) node.leftchild.accept(this);
+		if (node.rightchild != null) node.rightchild.accept(this);
+	}
+}
+
+public class VisitorPattern {
+	public static void main(String [] args) {
+		TreeNode root = new BlueNode(1,
+				new GreenNode(21,
+						new BlueNode(31, null, null),
+						new GreenNode(32, null, null)),
+				new GreenNode(22,
+						new BlueNode(33, null, null),
+						new GreenNode(34, null, null)));
+		root.accept(new Visitor());
+	}
+}