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