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Merge pull request #8218 from yavuztas/pr-BAEL-3408 

Source code for BAEL-3408
This commit is contained in:
Greg 2019-12-15 18:52:43 -05:00 committed by GitHub
parent c082640187 6154eb5f72
commit 2601170c2b
3 changed files with 278 additions and 0 deletions
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37
data-structures/src/main/java/com/baeldung/printbinarytree/BinaryTreeModel.java Normal file
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package com.baeldung.printbinarytree;
public class BinaryTreeModel {
private Object value;
private BinaryTreeModel left;
private BinaryTreeModel right;
public BinaryTreeModel(Object value) {
this.value = value;
}
public Object getValue() {
return value;
}
public void setValue(Object value) {
this.value = value;
}
public BinaryTreeModel getLeft() {
return left;
}
public void setLeft(BinaryTreeModel left) {
this.left = left;
}
public BinaryTreeModel getRight() {
return right;
}
public void setRight(BinaryTreeModel right) {
this.right = right;
}
}

63
data-structures/src/main/java/com/baeldung/printbinarytree/BinaryTreePrinter.java Normal file
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package com.baeldung.printbinarytree;
import java.io.PrintStream;
public class BinaryTreePrinter {
private BinaryTreeModel tree;
public BinaryTreePrinter(BinaryTreeModel tree) {
this.tree = tree;
}
private String traversePreOrder(BinaryTreeModel root) {
if (root == null) {
return "";
}
StringBuilder sb = new StringBuilder();
sb.append(root.getValue());
String pointerRight = "└──";
String pointerLeft = (root.getRight() != null) ? "├──" : "└──";
traverseNodes(sb, "", pointerLeft, root.getLeft(), root.getRight() != null);
traverseNodes(sb, "", pointerRight, root.getRight(), false);
return sb.toString();
}
private void traverseNodes(StringBuilder sb, String padding, String pointer, BinaryTreeModel node,
boolean hasRightSibling) {
if (node != null) {
sb.append("\n");
sb.append(padding);
sb.append(pointer);
sb.append(node.getValue());
StringBuilder paddingBuilder = new StringBuilder(padding);
if (hasRightSibling) {
paddingBuilder.append("│ ");
} else {
paddingBuilder.append(" ");
}
String paddingForBoth = paddingBuilder.toString();
String pointerRight = "└──";
String pointerLeft = (node.getRight() != null) ? "├──" : "└──";
traverseNodes(sb, paddingForBoth, pointerLeft, node.getLeft(), node.getRight() != null);
traverseNodes(sb, paddingForBoth, pointerRight, node.getRight(), false);
}
}
public void print(PrintStream os) {
os.print(traversePreOrder(tree));
}
}

178
data-structures/src/test/java/com/baeldung/printbinarytree/PrintingBinaryTreeModelUnitTest.java Normal file
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package com.baeldung.printbinarytree;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.baeldung.printbinarytree.BinaryTreeModel;
import com.baeldung.printbinarytree.BinaryTreePrinter;
public class PrintingBinaryTreeModelUnitTest {
private BinaryTreeModel balanced;
private BinaryTreeModel leftSkewed;
private BinaryTreeModel rightSkewed;
private OutputStream output;
@Before
public void setup() {
balanced = createBalancedTree();
leftSkewed = createLeftUnbalancedTree();
rightSkewed = createRightUnbalancedTree();
output = new ByteArrayOutputStream();
System.setOut(new PrintStream(output));
}
@After
public void tearDown() {
System.setOut(System.out);
}
private BinaryTreeModel createBalancedTree() {
BinaryTreeModel root = new BinaryTreeModel("root");
BinaryTreeModel node1 = new BinaryTreeModel("node1");
BinaryTreeModel node2 = new BinaryTreeModel("node2");
root.setLeft(node1);
root.setRight(node2);
BinaryTreeModel node3 = new BinaryTreeModel("node3");
BinaryTreeModel node4 = new BinaryTreeModel("node4");
node1.setLeft(node3);
node1.setRight(node4);
node2.setLeft(new BinaryTreeModel("node5"));
node2.setRight(new BinaryTreeModel("node6"));
BinaryTreeModel node7 = new BinaryTreeModel("node7");
node3.setLeft(node7);
node7.setLeft(new BinaryTreeModel("node8"));
node7.setRight(new BinaryTreeModel("node9"));
return root;
}
private BinaryTreeModel createLeftUnbalancedTree() {
BinaryTreeModel root = new BinaryTreeModel("root");
BinaryTreeModel node1 = new BinaryTreeModel("node1");
root.setLeft(node1);
root.setRight(new BinaryTreeModel("node2"));
BinaryTreeModel node3 = new BinaryTreeModel("node3");
node1.setLeft(node3);
BinaryTreeModel node4 = new BinaryTreeModel("node4");
node3.setLeft(node4);
BinaryTreeModel node5 = new BinaryTreeModel("node5");
node4.setLeft(node5);
BinaryTreeModel node6 = new BinaryTreeModel("node6");
node5.setLeft(node6);
BinaryTreeModel node7 = new BinaryTreeModel("node7");
node6.setLeft(node7);
node7.setLeft(new BinaryTreeModel("node8"));
return root;
}
private BinaryTreeModel createRightUnbalancedTree() {
BinaryTreeModel root = new BinaryTreeModel("root");
BinaryTreeModel node2 = new BinaryTreeModel("node2");
root.setLeft(new BinaryTreeModel("node1"));
root.setRight(node2);
BinaryTreeModel node3 = new BinaryTreeModel("node3");
node2.setRight(node3);
BinaryTreeModel node4 = new BinaryTreeModel("node4");
node3.setRight(node4);
BinaryTreeModel node5 = new BinaryTreeModel("node5");
node4.setRight(node5);
BinaryTreeModel node6 = new BinaryTreeModel("node6");
node5.setRight(node6);
BinaryTreeModel node7 = new BinaryTreeModel("node7");
node6.setRight(node7);
node7.setRight(new BinaryTreeModel("node8"));
return root;
}
@Test
public void givenBinaryTreeModelBalanced_whenPrintWithBinaryTreePrinter_thenProduceCorrectOutput() {
StringBuilder expected = new StringBuilder();
expected.append("root").append("\n");
expected.append("├──node1").append("\n");
expected.append("│ ├──node3").append("\n");
expected.append("│ │ └──node7").append("\n");
expected.append("│ │ ├──node8").append("\n");
expected.append("│ │ └──node9").append("\n");
expected.append("│ └──node4").append("\n");
expected.append("└──node2").append("\n");
expected.append(" ├──node5").append("\n");
expected.append(" └──node6");
new BinaryTreePrinter(balanced).print(System.out);
assertEquals(expected.toString(), output.toString());
}
@Test
public void givenBinaryTreeModelLeftUnbalanced_whenPrintWithBinaryTreePrinter_thenProduceCorrectOutput() {
StringBuilder expected = new StringBuilder();
expected.append("root").append("\n");
expected.append("├──node1").append("\n");
expected.append("│ └──node3").append("\n");
expected.append("│ └──node4").append("\n");
expected.append("│ └──node5").append("\n");
expected.append("│ └──node6").append("\n");
expected.append("│ └──node7").append("\n");
expected.append("│ └──node8").append("\n");
expected.append("└──node2");
new BinaryTreePrinter(leftSkewed).print(System.out);
assertEquals(expected.toString(), output.toString());
}
@Test
public void givenBinaryTreeModelRightUnbalanced_whenPrintWithBinaryTreePrinter_thenProduceCorrectOutput() {
StringBuilder expected = new StringBuilder();
expected.append("root").append("\n");
expected.append("├──node1").append("\n");
expected.append("└──node2").append("\n");
expected.append(" └──node3").append("\n");
expected.append(" └──node4").append("\n");
expected.append(" └──node5").append("\n");
expected.append(" └──node6").append("\n");
expected.append(" └──node7").append("\n");
expected.append(" └──node8");
new BinaryTreePrinter(rightSkewed).print(System.out);
assertEquals(expected.toString(), output.toString());
}
}