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Paul Campbell 2016-01-09 17:08:52 +00:00
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.gitignore vendored Normal file
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/target
/nbproject

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checkstyle.xml Normal file
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<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
"-//Puppy Crawl//DTD Check Configuration 1.3//EN"
"http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<!--
Checkstyle configuration that checks the sun coding conventions from:
- the Java Language Specification at
http://java.sun.com/docs/books/jls/second_edition/html/index.html
- the Sun Code Conventions at http://java.sun.com/docs/codeconv/
- the Javadoc guidelines at
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html
- the JDK Api documentation http://java.sun.com/j2se/docs/api/index.html
- some best practices
Checkstyle is very configurable. Be sure to read the documentation at
http://checkstyle.sf.net (or in your downloaded distribution).
Most Checks are configurable, be sure to consult the documentation.
To completely disable a check, just comment it out or delete it from the file.
Finally, it is worth reading the documentation.
-->
<module name="Checker">
<!--
If you set the basedir property below, then all reported file
names will be relative to the specified directory. See
http://checkstyle.sourceforge.net/5.x/config.html#Checker
<property name="basedir" value="${basedir}"/>
-->
<!-- Checks that a package-info.java file exists for each package. -->
<!-- See http://checkstyle.sf.net/config_javadoc.html#JavadocPackage -->
<module name="JavadocPackage"/>
<!-- Checks whether files end with a new line. -->
<!-- See http://checkstyle.sf.net/config_misc.html#NewlineAtEndOfFile -->
<module name="NewlineAtEndOfFile"/>
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<module name="Translation"/>
<!-- Checks for Size Violations. -->
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<module name="FileLength"/>
<!-- Checks for whitespace -->
<!-- See http://checkstyle.sf.net/config_whitespace.html -->
<module name="FileTabCharacter"/>
<!-- Miscellaneous other checks. -->
<!-- See http://checkstyle.sf.net/config_misc.html -->
<module name="RegexpSingleline">
<property name="format" value="\s+$"/>
<property name="minimum" value="0"/>
<property name="maximum" value="0"/>
<property name="message" value="Line has trailing spaces."/>
</module>
<!-- Checks for Headers -->
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<!-- <module name="Header"> -->
<!-- <property name="headerFile" value="${checkstyle.header.file}"/> -->
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<module name="TreeWalker">
<!-- Support @SuppressWarnings annotation -->
<!-- See http://checkstyle.sourceforge.net/config.html -->
<module name="SuppressWarningsHolder"/>
<module name="FileContentsHolder"/>
<!-- Checks for Javadoc comments. -->
<!-- See http://checkstyle.sf.net/config_javadoc.html -->
<module name="JavadocMethod">
<property name="scope" value="public"/>
</module>
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<!--<module name="JavadocVariable"/>-->
<module name="JavadocStyle"/>
<!-- Checks for Naming Conventions. -->
<!-- See http://checkstyle.sf.net/config_naming.html -->
<module name="ConstantName"/>
<module name="LocalFinalVariableName"/>
<module name="LocalVariableName"/>
<module name="MemberName"/>
<module name="MethodName"/>
<module name="PackageName"/>
<module name="ParameterName"/>
<module name="StaticVariableName"/>
<module name="TypeName"/>
<!-- Checks for imports -->
<!-- See http://checkstyle.sf.net/config_import.html -->
<module name="AvoidStarImport"/>
<module name="IllegalImport"/> <!-- defaults to sun.* packages -->
<module name="RedundantImport"/>
<module name="UnusedImports"/>
<!-- Checks for Size Violations. -->
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<module name="LineLength"/>
<module name="MethodLength"/>
<module name="ParameterNumber"/>
<!-- Checks for whitespace -->
<!-- See http://checkstyle.sf.net/config_whitespace.html -->
<module name="EmptyForIteratorPad"/>
<module name="GenericWhitespace"/>
<module name="MethodParamPad"/>
<module name="NoWhitespaceAfter"/>
<module name="NoWhitespaceBefore"/>
<module name="OperatorWrap"/>
<module name="ParenPad"/>
<module name="TypecastParenPad"/>
<module name="WhitespaceAfter"/>
<module name="WhitespaceAround"/>
<!-- Modifier Checks -->
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<module name="RightCurly"/>
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<property name="ignoreConstructorParameter" value="true"/>
<property name="ignoreSetter" value="true"/>
<property name="setterCanReturnItsClass" value="true"/>
</module>
<module name="IllegalInstantiation"/>
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<module name="ArrayTypeStyle"/>
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pom.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>net.kemitix</groupId>
<artifactId>node</artifactId>
<version>0.1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Node</name>
<description>A parent/children data structure</description>
<parent>
<groupId>net.kemitix</groupId>
<artifactId>kemitix-parent</artifactId>
<version>0.6.0</version>
</parent>
<issueManagement>
<url>https://github.com/kemitix/node/issues</url>
<system>GitHub Issues</system>
</issueManagement>
<scm>
<connection>scm:git:git@github.com:kemitix/node.git</connection>
<developerConnection>scm:git:git@github.com:kemitix/node.git</developerConnection>
<url>git@github.com:kemitix/node.git</url>
</scm>
<url>https://github.com/kemitix/node</url>
<inceptionYear>2016</inceptionYear>
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.6</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-core</artifactId>
<version>1.3</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>

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src/main/java/net/kemitix/node/Node.java Normal file
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package net.kemitix.node;
import java.util.List;
import java.util.Optional;
import java.util.Set;
/**
* An interface for tree node items.
*
* @author pcampbell
* @param <T> the type of data held in each node
*/
public interface Node<T> {
/**
* Fetch the data held within the node.
*
* @return the node's data
*/
T getData();
/**
* Fetch the parent node.
*
* <p>
* If the node is a root node, i.e. has no parent, then this will return
* null.
*
* @return the parent node
*/
Node<T> getParent();
/**
* Fetches the child nodes.
*
* @return the set of child nodes
*/
Set<Node<T>> getChildren();
/**
* Adds the child to the node.
*
* @param child the node to add
*/
void addChild(final Node<T> child);
/**
* Creates a new node and adds it as a child of the current node.
*
* @param child the child node's data
*
* @return the new child node
*/
Node<T> createChild(final T child);
/**
* Populates the tree with the path of nodes, each being a child of the
* previous node in the path.
*
* @param descendants the line of descendants from the current node
*/
void createDescendantLine(final List<T> descendants);
/**
* Looks for a child node and returns it, creating a new child node if one
* isn't found.
*
* @param child the child's data to search or create with
*
* @return the found or created child node
*/
Node<T> findOrCreateChild(final T child);
/**
* Fetches the node for the child if present.
*
* @param child the child's data to search for
*
* @return an {@link Optional} containing the child node if found
*/
Optional<Node<T>> getChild(final T child);
/**
* Checks if the node is an ancestor.
*
* @param node the potential ancestor
*
* @return true if the node is an ancestor
*/
boolean isChildOf(final Node<T> node);
/**
* Make the current node a direct child of the parent.
*
* @param parent the new parent node
*/
void setParent(final Node<T> parent);
/**
* Walks the node tree using the path to select each child.
*
* @param path the path to the desired child
*
* @return the child or null
*/
Optional<Node<T>> walkTree(final List<T> path);
}

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src/main/java/net/kemitix/node/NodeException.java Normal file
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package net.kemitix.node;
/**
* Represents an error within the tree node.
*
* @author pcampbell
*/
@SuppressWarnings("serial")
public class NodeException extends RuntimeException {
/**
* Constructor with message.
*
* @param message the message
*/
public NodeException(final String message) {
super(message);
}
}

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src/main/java/net/kemitix/node/NodeItem.java Normal file
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package net.kemitix.node;
import lombok.Getter;
import lombok.NonNull;
import java.util.HashSet;
import java.util.List;
import java.util.Optional;
import java.util.Set;
/**
* Represents a tree of nodes.
*
* @param <T> the type of data stored in each node
*
* @author pcampbell
*/
public class NodeItem<T> implements Node<T> {
@Getter
private final T data;
@Getter
private Node<T> parent;
@Getter
private Set<Node<T>> children;
/**
* Creates a root node.
*
* @param data the value of the node
*/
public NodeItem(@NonNull final T data) {
this(data, null);
}
/**
* Creates a node with a parent.
*
* @param data the value of the node
* @param parent the parent node
*/
public NodeItem(final T data, final Node<T> parent) {
this.data = data;
if (parent != null) {
setParent(parent);
}
this.children = new HashSet<>();
}
/**
* Make the current node a direct child of the parent.
*
* @param parent the new parent node
*/
@Override
public final void setParent(@NonNull final Node<T> parent) {
if (this.equals(parent) || parent.isChildOf(this)) {
throw new NodeException("Parent is a descendant");
}
if (this.parent != null) {
this.parent.getChildren().remove(this);
}
this.parent = parent;
parent.addChild(this);
}
/**
* Adds the child to the node.
*
* @param child the node to add
*/
@Override
public void addChild(@NonNull final Node<T> child) {
if (this.equals(child) || isChildOf(child)) {
throw new NodeException("Child is an ancestor");
}
children.add(child);
if (child.getParent() == null || !child.getParent().equals(this)) {
child.setParent(this);
}
}
/**
* Checks if the node is an ancestor.
*
* @param node the potential ancestor
*
* @return true if the node is an ancestor
*/
@Override
public boolean isChildOf(final Node<T> node) {
if (node.equals(parent)) {
return true;
}
if (parent != null) {
return parent.isChildOf(node);
}
return false;
}
/**
* Walks the node tree using the path to select each child.
*
* @param path the path to the desired child
*
* @return the child or null
*/
@Override
public Optional<Node<T>> walkTree(@NonNull final List<T> path) {
if (path.size() > 0) {
Optional<Node<T>> found = children.stream()
.filter((Node<T> child) -> path.get(0)
.equals(child.getData()))
.findFirst();
if (found.isPresent()) {
if (path.size() > 1) {
return found.get().walkTree(path.subList(1, path.size()));
}
return found;
}
}
return Optional.empty();
}
/**
* Populates the tree with the path of nodes, each being a child of the
* previous node in the path.
*
* @param descendants the line of descendants from the current node
*/
@Override
public void createDescendantLine(@NonNull final List<T> descendants) {
if (!descendants.isEmpty()) {
findOrCreateChild(descendants.get(0))
.createDescendantLine(
descendants.subList(1, descendants.size()));
}
}
/**
* Looks for a child node and returns it, creating a new child node if one
* isn't found.
*
* @param child the child's data to search or create with
*
* @return the found or created child node
*/
@Override
public Node<T> findOrCreateChild(@NonNull final T child) {
Optional<Node<T>> found = getChild(child);
if (found.isPresent()) {
return found.get();
} else {
return createChild(child);
}
}
/**
* Fetches the node for the child if present.
*
* @param child the child's data to search for
*
* @return an {@link Optional} containing the child node if found
*/
@Override
public Optional<Node<T>> getChild(@NonNull final T child) {
return children.stream()
.filter((Node<T> t) -> t.getData().equals(child))
.findAny();
}
/**
* Creates a new node and adds it as a child of the current node.
*
* @param child the child node's data
*
* @return the new child node
*/
@Override
public Node<T> createChild(@NonNull final T child) {
return new NodeItem<>(child, this);
}
}

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src/main/java/net/kemitix/node/package-info.java Normal file
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/**
* Tree Node implementation.
*/
package net.kemitix.node;

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src/test/java/net/kemitix/node/NodeExceptionTest.java Normal file
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package net.kemitix.node;
import net.kemitix.node.NodeException;
import org.junit.Test;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
/**
* Tests for {@link NodeException}.
*
* @author pcampbell
*/
public class NodeExceptionTest {
/**
* Class under test.
*/
private NodeException nodeException;
/**
* Test that message provided to constructor is returned.
*/
@Test
public void shouldReturnConstructorMessage() {
//given
final String message = "this is the message";
//when
nodeException = new NodeException(message);
//then
assertThat(nodeException.getMessage(), is(message));
}
}

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src/test/java/net/kemitix/node/NodeItemTest.java Normal file
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package net.kemitix.node;
import org.junit.Test;
import java.util.Arrays;
import java.util.Collections;
import java.util.Optional;
import static org.hamcrest.CoreMatchers.hasItem;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;
/**
* Test for {@link NodeItem}.
*
* @author pcampbell
*/
public class NodeItemTest {
/**
* Class under test.
*/
private Node<String> node;
/**
* Test {@link NodeItem#Node(java.lang.Object) } that node data is
* recoverable.
*/
@Test
public void shouldReturnNodeData() {
//given
final String data = "this node data";
//when
node = new NodeItem<>(data);
//then
assertThat(node.getData(), is(data));
}
/**
* Test {@link NodeItem#Node(java.lang.Object) } that passing null as node
* data throws exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenDataIsNull() {
//when
node = new NodeItem<>(null);
}
/**
* Test {@link NodeItem#Node(java.lang.Object) } that default node parent is
* null.
*/
@Test
public void shouldHaveNullForDefaulParent() {
//given
node = new NodeItem<>("data");
//then
assertNull(node.getParent());
}
/**
* Test {@link NodeItem#Node(java.lang.Object, net.kemitix.node.Node) } that
* provided node parent is returned.
*/
@Test
public void shouldReturnNodeParent() {
//given
Node<String> parent = new NodeItem<>("parent");
//when
node = new NodeItem<>("subject", parent);
//then
assertThat(node.getParent(), is(parent));
}
/**
* Test {@link NodeItem#Node(java.lang.Object, net.kemitix.node.Node) } that
* setting the parent on a node where the proposed parent is a child of the
* node throws an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowNEWhenSettingParentToAChild() {
//given
node = new NodeItem<>("subject");
Node<String> child = new NodeItem<>("child", node);
//when
node.setParent(child);
}
/**
* Test {@link NodeItem#Node(java.lang.Object, net.kemitix.node.Node) } that
* when parent is added to created node, the created node is now a child of
* the parent.
*/
@Test
public void shouldAddNewNodeAsChildToParent() {
//given
Node<String> parent = new NodeItem<>("parent");
//when
node = new NodeItem<>("subject", parent);
//then
assertThat(parent.getChildren(), hasItem(node));
}
/**
* Test {@link NodeItem#setParent(net.kemitix.node.Node) } that we return
* the same parent when set.
*/
@Test
public void shouldReturnSetParent() {
//given
node = new NodeItem<>("subject");
Node<String> parent = new NodeItem<>("parent");
//when
node.setParent(parent);
//then
assertThat(node.getParent(), is(parent));
}
/**
* Test {@link NodeItem#setParent(net.kemitix.node.Node) } that we throw an
* exception when passed null.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenSetParentNull() {
//given
node = new NodeItem<>("subject");
//when
node.setParent(null);
}
/**
* Test {@link NodeItem#setParent(net.kemitix.node.Node) } that we throw an
* exceptions when attempting to node as its own parent.
*/
@Test(expected = NodeException.class)
public void shouldThrowNEWhenSetParentSelf() {
//given
node = new NodeItem<>("subject");
//when
node.setParent(node);
}
/**
* Test {@link NodeItem#setParent(net.kemitix.node.Node) } that when a node
* with an existing parent is assigned a new parent, that the old parent no
* longer sees it as one of its children.
*/
@Test
public void shouldUpdateOldParentWhenNodeSetToNewParent() {
//given
node = new NodeItem<>("subject");
Node<String> child = node.createChild("child");
Node<String> newParent = new NodeItem<>("newParent");
//when
child.setParent(newParent);
//then
assertThat(child.getParent(), is(newParent));
assertFalse(node.getChild("child").isPresent());
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that when a node
* is added as a child to another node, that it's previous parent no longer
* has it as a child.
*/
@Test
public void shouldRemoveNodeFromOldParentWhenAddedAsChildToNewParent() {
//given
node = new NodeItem<>("subject");
Node<String> child = node.createChild("child");
Node<String> newParent = new NodeItem<>("newParent");
//when
newParent.addChild(child);
//then
assertThat(child.getParent(), is(newParent));
assertFalse(node.getChild("child").isPresent());
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding null
* as a child throws an exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenAddingNullAsChild() {
//given
node = new NodeItem<>("subject");
//when
node.addChild(null);
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding a
* child is returned.
*/
@Test
public void shouldReturnAddedChild() {
//given
Node<String> child = new NodeItem<>("child");
node = new NodeItem<>("subject");
//when
node.addChild(child);
//then
assertThat(node.getChildren(), hasItem(child));
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding a node
* as it's own child throws an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowNEWhenAddingANodeAsOwnChild() {
//given
node = new NodeItem<>("subject");
//then
node.addChild(node);
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding a node
* to itself as a child causes an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingSelfAsChild() {
//given
node = new NodeItem<>("subject");
//when
node.addChild(node);
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding the
* parent to node causes an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingParentAsChild() {
//given
Node<String> parent = new NodeItem<>("parent");
node = new NodeItem<>("subject", parent);
//when
node.addChild(parent);
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding the
* grandparent to node causes an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingGrandParentAsChild() {
//given
Node<String> grandParent = new NodeItem<>("grandparent");
Node<String> parent = new NodeItem<>("parent", grandParent);
node = new NodeItem<>("subject", parent);
//when
node.addChild(grandParent);
}
/**
* Test {@link NodeItem#addChild(net.kemitix.node.Node) } that adding a
* child to a node, sets the child's parent node.
*/
@Test
public void shouldSetParentOnChildWhenAddedAsChild() {
//given
Node<String> child = new NodeItem<>("child");
node = new NodeItem<>("subject");
//when
node.addChild(child);
//then
assertThat(child.getParent(), is(node));
}
/**
* Test {@link NodeItem#walkTree(java.util.List) } that we can walk a tree
* to the target node.
*/
@Test
public void shouldWalkTreeToNode() {
//given
final String grandparent = "grandparent";
Node<String> grandParentNode = new NodeItem<>(grandparent);
final String parent = "parent";
Node<String> parentNode = new NodeItem<>(parent, grandParentNode);
final String subject = "subject";
node = new NodeItem<>(subject, parentNode);
//when
Optional<Node<String>> result = grandParentNode.walkTree(Arrays.asList(
parent, subject));
//then
assertTrue(result.isPresent());
assertThat(result.get(), is(node));
}
/**
* Test {@link NodeItem#walkTree(java.util.List) } that we get an empty
* {@link Optional} when walking a path that doesn't exist.
*/
@Test
public void shouldNotFindNonExistantChildNode() {
//given
final String parent = "parent";
Node<String> parentNode = new NodeItem<>(parent);
final String subject = "subject";
node = new NodeItem<>(subject, parentNode);
//when
Optional<Node<String>> result = parentNode.walkTree(Arrays.asList(
subject, "no child"));
//then
assertFalse(result.isPresent());
}
/**
* Test {@link NodeItem#walkTree(java.util.List) } that when we pass null we
* get an exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNEWhenWalkTreeNull() {
//given
node = new NodeItem<>("subject");
//when
node.walkTree(null);
}
/**
* Test {@link NodeItem#walkTree(java.util.List) } that when we pass an
* empty path we get and empty {@link Optional} as a result.
*/
@Test
public void shouldReturnEmptyForEmptyWalkTreePath() {
//given
node = new NodeItem<>("subject");
//when
node.walkTree(Collections.emptyList());
}
/**
* Test {@link NodeItem#createDescendantLine(java.util.List) } that we can
* create a chain of descendant nodes.
*/
@Test
public void shouldCreateDescendantNodes() {
//given
node = new NodeItem<>("subject");
final String alphaData = "alpha";
final String betaData = "beta";
final String gammaData = "gamma";
//when
node.createDescendantLine(
Arrays.asList(alphaData, betaData, gammaData));
//then
final Optional<Node<String>> alphaOptional = node.getChild(alphaData);
assertTrue(alphaOptional.isPresent());
Node<String> alpha = alphaOptional.get();
assertThat(alpha.getParent(), is(node));
final Optional<Node<String>> betaOptional = alpha.getChild(betaData);
assertTrue(betaOptional.isPresent());
Node<String> beta = betaOptional.get();
assertThat(beta.getParent(), is(alpha));
final Optional<Node<String>> gammaOptional = beta.getChild(gammaData);
assertTrue(gammaOptional.isPresent());
Node<String> gamma = gammaOptional.get();
assertThat(gamma.getParent(), is(beta));
}
/**
* Test {@link NodeItem#createDescendantLine(java.util.List) } that if we
* pass null to create a chain of descendant nodes we get an exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenCreateDescendantNull() {
//given
node = new NodeItem<>("subject");
//when
node.createDescendantLine(null);
}
/**
* Test {@link NodeItem#createDescendantLine(java.util.List) } that if we
* pass an empty list nothing is changed.
*/
@Test
public void shouldChangeNothingWhenCreateDescendantEmpty() {
//given
node = new NodeItem<>("subject");
//when
node.createDescendantLine(Collections.emptyList());
//then
assertThat(node.getChildren().size(), is(0));
}
/**
* Test {@link NodeItem#findOrCreateChild(java.lang.Object) } that we can
* find a child of a node.
*/
@Test
public void shouldFindExistingChildNode() {
//given
node = new NodeItem<>("subject");
final String childData = "child";
Node<String> child = new NodeItem<>(childData, node);
//when
Node<String> found = node.findOrCreateChild(childData);
//then
assertThat(found, is(child));
}
/**
* Test {@link NodeItem#findOrCreateChild(java.lang.Object) } that we create
* a missing child of a node.
*/
@Test
public void shouldFindCreateNewChildNode() {
//given
node = new NodeItem<>("subject");
final String childData = "child";
//when
Node<String> found = node.findOrCreateChild(childData);
//then
assertThat(found.getData(), is(childData));
}
/**
* Test {@link NodeItem#findOrCreateChild(java.lang.Object) } that if we
* pass null we get an exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEFWhenFindOrCreateChildNull() {
//given
node = new NodeItem<>("subject");
//when
node.findOrCreateChild(null);
}
/**
* Test {@link NodeItem#getChild(java.lang.Object) } that we can get the
* node for a child.
*/
@Test
public void shouldGetChild() {
//given
node = new NodeItem<>("subject");
final String childData = "child";
Node<String> child = new NodeItem<>(childData);
node.addChild(child);
//when
Optional<Node<String>> found = node.getChild(childData);
//then
assertTrue(found.isPresent());
assertThat(found.get(), is(child));
}
/**
* Test {@link NodeItem#getChild(java.lang.Object) } that we throw an
* exception when passed null.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenGetChildNull() {
//given
node = new NodeItem<>("subject");
//when
node.getChild(null);
}
/**
* Test {@link NodeItem#createChild(java.lang.Object) } that we create a
* child as a child of the current node and with the current node as its
* parent.
*/
@Test
public void shoudCreateChild() {
//given
node = new NodeItem<>("subject");
final String childData = "child";
//when
Node<String> child = node.createChild(childData);
//then
assertThat(child.getParent(), is(node));
final Optional<Node<String>> foundChild = node.getChild(childData);
assertTrue(foundChild.isPresent());
assertThat(foundChild.get(), is(child));
}
/**
* Test that we throw an exception when passed null.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenCreateChildNull() {
//given
node = new NodeItem<>("subject");
//when
node.createChild(null);
}
}