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Merge pull request #4 from kemitix/named-nodes

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Named nodes
This commit is contained in:
Paul Campbell 2016-05-24 14:06:07 +01:00
commit a5c1fc72fd
5 changed files with 833 additions and 217 deletions
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1
node.iml
View file

@ -14,5 +14,6 @@
<orderEntry type="library" scope="TEST" name="Maven: org.projectlombok:lombok:1.16.8" level="project" />
<orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
<orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
<orderEntry type="library" scope="TEST" name="Maven: org.assertj:assertj-core:3.4.1" level="project" />
</component>
</module>

10
pom.xml
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@ -14,6 +14,10 @@
<version>0.6.0</version>
</parent>
<properties>
<assertj.version>3.4.1</assertj.version>
</properties>
<issueManagement>
<url>https://github.com/kemitix/node/issues</url>
<system>GitHub Issues</system>
@ -48,5 +52,11 @@
<version>1.3</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>

90
src/main/java/net/kemitix/node/Node.java
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@ -13,6 +13,20 @@ import java.util.Set;
*/
public interface Node<T> {
/**
* Fetch the name of the node.
*
* @return the name of the node
*/
String getName();
/**
* Sets the explicit name for a node.
*
* @param name the new name
*/
void setName(String name);
/**
* Fetch the data held within the node.
*
@ -20,6 +34,13 @@ public interface Node<T> {
*/
T getData();
/**
* Returns true if the node is empty (has no data).
*
* @return true is data is null
*/
boolean isEmpty();
/**
* Fetch the parent node.
* <p>
@ -30,6 +51,13 @@ public interface Node<T> {
*/
Node<T> getParent();
/**
* Make the current node a direct child of the parent.
*
* @param parent the new parent node
*/
void setParent(final Node<T> parent);
/**
* Fetches the child nodes.
*
@ -89,13 +117,6 @@ public interface Node<T> {
*/
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.
*
@ -105,4 +126,59 @@ public interface Node<T> {
*/
Optional<Node<T>> walkTree(final List<T> path);
/**
* Places the node in the tree under by the path. Intervening empty
* nodes are created as needed.
*
* @param node the node to place
* @param path the path to contain the new node
*/
void placeNodeIn(Node<T> node, String... path);
/**
* Searches for a child with the name given.
*
* @param name the name of the child
*
* @return an Optional containing the child found or empty
*/
Optional<Node<T>> findChildNamed(String name);
/**
* Returns the child with the given name. If one can't be found a
* NodeException is thrown.
*
* @param name the name of the child
*
* @return the node
*/
Node<T> getChildNamed(String name);
/**
* Draw a representation of the tree.
*
* @param depth current depth for recursion
*
* @return a representation of the tree
*/
String drawTree(int depth);
/**
* Returns true if the Node has a name.
*
* @return true if the node has a name
*/
boolean isNamed();
/**
* Remove the node from the children.
*
* @param node the node to be removed
*/
void removeChild(Node<T> node);
/**
* Removes the parent from the node. Makes the node into a new root node.
*/
void removeParent();
}

322
src/main/java/net/kemitix/node/NodeItem.java
View file

@ -1,9 +1,11 @@
package net.kemitix.node;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.function.Function;
/**
* Represents a tree of nodes.
@ -16,33 +18,108 @@ public class NodeItem<T> implements Node<T> {
private final T data;
private Node<T> parent;
private final Set<Node<T>> children = new HashSet<>();
private Function<Node<T>, String> nameSupplier;
private Node<T> parent;
private String name;
/**
* Creates a root node.
* Create named root node.
*
* @param data the value of the node
* @param data the data or null
* @param name the name
*/
public NodeItem(final T data, final String name) {
this(data);
this.name = name;
}
/**
* Create unnamed root node.
*
* @param data the data or null
*/
public NodeItem(final T data) {
this(data, null);
this.data = data;
this.nameSupplier = (n) -> null;
}
/**
* Creates root node with a name supplier.
*
* @param data the data or null
* @param nameSupplier the name supplier function
*/
public NodeItem(
final T data, final Function<Node<T>, String> nameSupplier) {
this(data);
this.nameSupplier = nameSupplier;
name = generateName();
}
/**
* Creates a node with a parent.
*
* @param data the value of the node
* @param data the data or null
* @param parent the parent node
*/
public NodeItem(final T data, final Node<T> parent) {
if (data == null) {
throw new NullPointerException("data");
}
this.data = data;
if (parent != null) {
setParent(parent);
setParent(parent);
this.name = generateName();
}
/**
* Creates a named node with a parent.
*
* @param data the data or null
* @param name the name
* @param parent the parent node
*/
public NodeItem(final T data, final String name, final Node<T> parent) {
this.data = data;
this.name = name;
setParent(parent);
}
/**
* Creates a node with a name supplier and a parent.
*
* @param data the data or null
* @param nameSupplier the name supplier function
* @param parent the parent node
*/
public NodeItem(
final T data, final Function<Node<T>, String> nameSupplier,
final Node<T> parent) {
this(data, nameSupplier);
setParent(parent);
}
private String generateName() {
return getNameSupplier().apply(this);
}
private Function<Node<T>, String> getNameSupplier() {
if (nameSupplier != null) {
return nameSupplier;
}
// no test for parent as root nodes will always have a default name
// supplier
return ((NodeItem<T>) parent).getNameSupplier();
}
@Override
public String getName() {
return name;
}
@Override
public void setName(final String name) {
this.name = name;
}
@Override
@ -50,6 +127,11 @@ public class NodeItem<T> implements Node<T> {
return data;
}
@Override
public boolean isEmpty() {
return data == null;
}
@Override
public Node<T> getParent() {
return parent;
@ -60,26 +142,6 @@ public class NodeItem<T> implements Node<T> {
return children;
}
/**
* Make the current node a direct child of the parent.
*
* @param parent the new parent node
*/
@Override
public final void setParent(final Node<T> parent) {
if (parent == null) {
throw new NullPointerException("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.
*
@ -93,6 +155,14 @@ public class NodeItem<T> implements Node<T> {
if (this.equals(child) || isChildOf(child)) {
throw new NodeException("Child is an ancestor");
}
if (child.isNamed()) {
final Optional<Node<T>> existingChild = findChildNamed(
child.getName());
if (existingChild.isPresent() && existingChild.get() != child) {
throw new NodeException(
"Node with that name already exists here");
}
}
children.add(child);
if (child.getParent() == null || !child.getParent().equals(this)) {
child.setParent(this);
@ -100,40 +170,18 @@ public class NodeItem<T> implements Node<T> {
}
/**
* Checks if the node is an ancestor.
* Creates a new node and adds it as a child of the current node.
*
* @param node the potential ancestor
* @param child the child node's data
*
* @return true if the node is an ancestor
* @return the new child node
*/
@Override
public boolean isChildOf(final Node<T> node) {
return parent != null && (node.equals(parent) || parent.isChildOf(
node));
}
/**
* 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(final List<T> path) {
if (path == null) {
throw new NullPointerException("path");
public Node<T> createChild(final T child) {
if (child == null) {
throw new NullPointerException("child");
}
if (path.size() > 0) {
Optional<Node<T>> found = getChild(path.get(0));
if (found.isPresent()) {
if (path.size() > 1) {
return found.get().walkTree(path.subList(1, path.size()));
}
return found;
}
}
return Optional.empty();
return new NodeItem<>(child, this);
}
/**
@ -187,18 +235,158 @@ public class NodeItem<T> implements Node<T> {
}
/**
* Creates a new node and adds it as a child of the current node.
* Checks if the node is an ancestor.
*
* @param child the child node's data
* @param node the potential ancestor
*
* @return the new child node
* @return true if the node is an ancestor
*/
@Override
public Node<T> createChild(final T child) {
if (child == null) {
throw new NullPointerException("child");
public boolean isChildOf(final Node<T> node) {
return parent != null && (node.equals(parent) || parent.isChildOf(
node));
}
/**
* Make the current node a direct child of the parent.
*
* @param parent the new parent node
*/
@Override
public final void setParent(final Node<T> parent) {
if (parent == null) {
throw new NullPointerException("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);
}
/**
* 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(final List<T> path) {
if (path == null) {
throw new NullPointerException("path");
}
if (path.size() > 0) {
Optional<Node<T>> found = getChild(path.get(0));
if (found.isPresent()) {
if (path.size() > 1) {
return found.get().walkTree(path.subList(1, path.size()));
}
return found;
}
}
return Optional.empty();
}
@Override
public void placeNodeIn(final Node<T> nodeItem, final String... path) {
if (path.length == 0) {
if (!nodeItem.isNamed()) { // nothing to conflict with
addChild(nodeItem);
return;
}
final Optional<Node<T>> childNamed = findChildNamed(
nodeItem.getName());
if (!childNamed.isPresent()) { // nothing with the same name exists
addChild(nodeItem);
return;
}
// we have an existing node with the same name
final Node<T> existing = childNamed.get();
if (!existing.isEmpty()) {
throw new NodeException(
"A non-empty node with that name already exists here");
} else {
existing.getChildren().forEach(nodeItem::addChild);
existing.removeParent();
addChild(nodeItem);
}
return;
}
String item = path[0];
final Optional<Node<T>> childNamed = findChildNamed(item);
Node<T> child;
if (!childNamed.isPresent()) {
child = new NodeItem<>(null, item, this);
} else {
child = childNamed.get();
}
child.placeNodeIn(nodeItem, Arrays.copyOfRange(path, 1, path.length));
}
@Override
public Optional<Node<T>> findChildNamed(final String named) {
if (named == null) {
throw new NullPointerException("name");
}
return children.stream()
.filter((Node<T> t) -> t.getName().equals(named))
.findAny();
}
@Override
public Node<T> getChildNamed(final String named) {
final Optional<Node<T>> optional = findChildNamed(named);
if (optional.isPresent()) {
return optional.get();
}
throw new NodeException("Named child not found");
}
@Override
public String drawTree(final int depth) {
final StringBuilder sb = new StringBuilder();
final String unnamed = "(unnamed)";
if (isNamed()) {
sb.append(String.format("[%1$" + (depth + name.length()) + "s]\n",
name));
} else if (!children.isEmpty()) {
sb.append(
String.format("[%1$" + (depth + unnamed.length()) + "s]\n",
unnamed));
}
getChildren().stream().forEach(c -> sb.append(c.drawTree(depth + 1)));
return sb.toString();
}
@Override
public boolean isNamed() {
return name != null && name.length() > 0;
}
@Override
public void removeChild(final Node<T> node) {
if (children.remove(node)) {
node.removeParent();
}
}
@Override
public void removeParent() {
if (parent != null) {
Node<T> oldParent = parent;
Function<Node<T>, String> supplier = getNameSupplier();
parent = null;
oldParent.removeChild(this);
if (this.nameSupplier == null) {
// this is now a root node, so must provide a default name
// supplier
this.nameSupplier = supplier;
}
}
return new NodeItem<>(child, this);
}
}

627
src/test/java/net/kemitix/node/NodeItemTest.java
View file

@ -1,13 +1,15 @@
package net.kemitix.node;
import lombok.val;
import org.junit.Assert;
import org.assertj.core.api.SoftAssertions;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import static org.hamcrest.CoreMatchers.hasItem;
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.nullValue;
import static org.assertj.core.api.Assertions.assertThat;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Arrays;
import java.util.Collections;
import java.util.Optional;
@ -19,32 +21,51 @@ import java.util.Optional;
*/
public class NodeItemTest {
/**
* Class under test.
*/
@Rule
public ExpectedException exception = ExpectedException.none();
private Node<String> node;
/**
* Test that node data is recoverable.
*/
@Test
public void shouldReturnNodeData() {
public void getDataReturnsData() {
//given
val data = "this node data";
//when
node = new NodeItem<>(data);
//then
Assert.assertThat("can get the data from a node", node.getData(),
is(data));
assertThat(node.getData()).as("can get the data from a node").
isSameAs(data);
}
/**
* Test that passing null as node data throws exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenDataIsNull() {
@Test
public void canCreateAnEmptyAndUnnamedNode() {
//when
node = new NodeItem<>(null);
//then
SoftAssertions softly = new SoftAssertions();
softly.assertThat(node.isEmpty()).as("node is empty").isTrue();
softly.assertThat(node.isNamed()).as("node is unnamed").isFalse();
softly.assertAll();
}
@Test
public void canCreateNodeWithParentAndCustomNameSupplier() {
//given
node = new NodeItem<>(null, n -> "root name supplier");
//when
val child = new NodeItem<>(null, n -> "overridden", node);
//then
assertThat(child.getName()).isEqualTo("overridden");
}
@Test
public void canSetName() {
//given
node = new NodeItem<>(null);
//when
node.setName("named");
//then
assertThat(node.getName()).isEqualTo("named");
}
/**
@ -53,10 +74,10 @@ public class NodeItemTest {
@Test
public void shouldHaveNullForDefaultParent() {
//given
node = new NodeItem<>("data");
node = new NodeItem<>("data", Node::getData);
//then
Assert.assertThat("node created without a parent has null as parent",
node.getParent(), nullValue());
assertThat(node.getParent()).as(
"node created without a parent has null as parent").isNull();
}
/**
@ -65,23 +86,26 @@ public class NodeItemTest {
@Test
public void shouldReturnNodeParent() {
//given
val parent = new NodeItem<String>("parent");
val parent = new NodeItem<String>("parent", Node::getData);
//when
node = new NodeItem<>("subject", parent);
//then
Assert.assertThat("node created with a parent can return the parent",
node.getParent(), is(parent));
assertThat(node.getParent()).as(
"node created with a parent can return the parent")
.isSameAs(parent);
}
/**
* Test 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() {
@Test
public void setParentShouldThrowNodeExceptionWhenParentIsAChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val child = new NodeItem<String>("child", node);
exception.expect(NodeException.class);
exception.expectMessage("Parent is a descendant");
//when
node.setParent(child);
}
@ -91,16 +115,16 @@ public class NodeItemTest {
* child of the parent.
*/
@Test
@SuppressWarnings("unchecked")
public void shouldAddNewNodeAsChildToParent() {
//given
val parent = new NodeItem<String>("parent");
val parent = new NodeItem<String>("parent", Node::getData);
//when
node = new NodeItem<>("subject", parent);
//then
Assert.assertThat(
assertThat(parent.getChildren()).as(
"when a node is created with a parent, the parent has the new"
+ " node among it's children", parent.getChildren(),
hasItem(node));
+ " node among it's children").contains(node);
}
/**
@ -109,23 +133,25 @@ public class NodeItemTest {
@Test
public void shouldReturnSetParent() {
//given
node = new NodeItem<>("subject");
val parent = new NodeItem<String>("parent");
node = new NodeItem<>("subject", Node::getData);
val parent = new NodeItem<String>("parent", Node::getData);
//when
node.setParent(parent);
//then
Assert.assertThat(
assertThat(node.getParent()).as(
"when a node is assigned a new parent that parent can be "
+ "returned", node.getParent(), is(parent));
+ "returned").isSameAs(parent);
}
/**
* Test that we throw an exception when passed null.
*/
@Test(expected = NullPointerException.class)
@Test
public void shouldThrowNPEWhenSetParentNull() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("parent");
//when
node.setParent(null);
}
@ -134,10 +160,12 @@ public class NodeItemTest {
* Test that we throw an exceptions when attempting to node as its own
* parent.
*/
@Test(expected = NodeException.class)
public void shouldThrowNEWhenSetParentSelf() {
@Test
public void setParentShouldThrowNodeExceptionWhenParentIsSelf() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NodeException.class);
exception.expectMessage("Parent is a descendant");
//when
node.setParent(node);
}
@ -149,19 +177,18 @@ public class NodeItemTest {
@Test
public void shouldUpdateOldParentWhenNodeSetToNewParent() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val child = node.createChild("child");
val newParent = new NodeItem<String>("newParent");
val newParent = new NodeItem<String>("newParent", Node::getData);
//when
child.setParent(newParent);
//then
Assert.assertThat(
assertThat(child.getParent()).as(
"when a node is assigned a new parent, the old parent is "
+ "replaced", child.getParent(), is(newParent));
Assert.assertThat(
+ "replaced").isSameAs(newParent);
assertThat(node.getChild("child").isPresent()).as(
"when a node is assigned a new parent, the old parent no "
+ "longer has the node among it's children",
node.getChild("child").isPresent(), is(false));
+ "longer has the node among it's children").isFalse();
}
/**
@ -171,30 +198,31 @@ public class NodeItemTest {
@Test
public void shouldRemoveNodeFromOldParentWhenAddedAsChildToNewParent() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val child = node.createChild("child");
val newParent = new NodeItem<String>("newParent");
val newParent = new NodeItem<String>("newParent", Node::getData);
//when
newParent.addChild(child);
//then
Assert.assertThat(
assertThat(child.getParent()).as(
"when a node with an existing parent is added as a child "
+ "to another node, then the old parent is replaced",
child.getParent(), is(newParent));
Assert.assertThat(
+ "to another node, then the old parent is replaced")
.isSameAs(newParent);
assertThat(node.getChild("child").isPresent()).as(
"when a node with an existing parent is added as a child to "
+ "another node, then the old parent no longer has "
+ "the node among it's children",
node.getChild("child").isPresent(), is(false));
+ "the node among it's children").isFalse();
}
/**
* Test that adding null as a child throws an exception.
*/
@Test(expected = NullPointerException.class)
@Test
public void shouldThrowNPEWhenAddingNullAsChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("child");
//when
node.addChild(null);
}
@ -203,25 +231,28 @@ public class NodeItemTest {
* Test that adding a child is returned.
*/
@Test
@SuppressWarnings("unchecked")
public void shouldReturnAddedChild() {
//given
node = new NodeItem<>("subject");
val child = new NodeItem<String>("child");
node = new NodeItem<>("subject", Node::getData);
val child = new NodeItem<String>("child", Node::getData);
//when
node.addChild(child);
//then
Assert.assertThat(
assertThat(node.getChildren()).as(
"when a node is added as a child, the node is among the "
+ "children", node.getChildren(), hasItem(child));
+ "children").contains(child);
}
/**
* Test that adding a node as it's own child throws an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowNEWhenAddingANodeAsOwnChild() {
@Test
public void addChildShouldThrowNodeExceptionWhenAddingANodeAsOwnChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NodeException.class);
exception.expectMessage("Child is an ancestor");
//then
node.addChild(node);
}
@ -229,10 +260,12 @@ public class NodeItemTest {
/**
* Test that adding a node to itself as a child causes an exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingSelfAsChild() {
@Test
public void addChildShouldThrowNodeExceptionWhenAddingSelfAsChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NodeException.class);
exception.expectMessage("Child is an ancestor");
//when
node.addChild(node);
}
@ -241,11 +274,13 @@ public class NodeItemTest {
* Test that adding the parent of a node to the node as a child causes an
* exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingParentAsChild() {
@Test
public void addChildShouldThrowNodeExceptionWhenChildIsParent() {
//given
val parent = new NodeItem<String>("parent");
val parent = new NodeItem<String>("parent", Node::getData);
node = new NodeItem<>("subject", parent);
exception.expect(NodeException.class);
exception.expectMessage("Child is an ancestor");
//when
node.addChild(parent);
}
@ -254,12 +289,14 @@ public class NodeItemTest {
* Test that adding the grandparent to a node as a child causes an
* exception.
*/
@Test(expected = NodeException.class)
public void shouldThrowWhenAddingGrandParentAsChild() {
@Test
public void addChildShouldThrowNodeExceptionWhenAddingGrandParentAsChild() {
//given
val grandParent = new NodeItem<String>("grandparent");
val grandParent = new NodeItem<String>("grandparent", Node::getData);
val parent = new NodeItem<String>("parent", grandParent);
node = new NodeItem<>("subject", parent);
exception.expect(NodeException.class);
exception.expectMessage("Child is an ancestor");
//when
node.addChild(grandParent);
}
@ -270,14 +307,14 @@ public class NodeItemTest {
@Test
public void shouldSetParentOnChildWhenAddedAsChild() {
//given
val child = new NodeItem<String>("child");
node = new NodeItem<>("subject");
val child = new NodeItem<String>("child", Node::getData);
node = new NodeItem<>("subject", Node::getData);
//when
node.addChild(child);
//then
Assert.assertThat(
assertThat(child.getParent()).as(
"when a node is added as a child, the child has the node as "
+ "its parent", child.getParent(), is(node));
+ "its parent").isSameAs(node);
}
/**
@ -287,7 +324,7 @@ public class NodeItemTest {
public void shouldWalkTreeToNode() {
//given
val grandparent = "grandparent";
val grandParentNode = new NodeItem<String>(grandparent);
val grandParentNode = new NodeItem<String>(grandparent, Node::getData);
val parent = "parent";
val parentNode = new NodeItem<String>(parent, grandParentNode);
val subject = "subject";
@ -295,12 +332,12 @@ public class NodeItemTest {
//when
val result = grandParentNode.walkTree(Arrays.asList(parent, subject));
//then
Assert.assertThat("when we walk the tree to a node it is found",
result.isPresent(), is(true));
assertThat(result.isPresent()).as(
"when we walk the tree to a node it is found").isTrue();
if (result.isPresent()) {
Assert.assertThat(
"when we walk the tree to a node the correct node is found",
result.get(), is(node));
assertThat(result.get()).as(
"when we walk the tree to a node the correct node is found")
.isSameAs(node);
}
}
@ -312,24 +349,26 @@ public class NodeItemTest {
public void shouldNotFindNonExistentChildNode() {
//given
val parent = "parent";
val parentNode = new NodeItem<String>(parent);
val parentNode = new NodeItem<String>(parent, Node::getData);
val subject = "subject";
node = new NodeItem<>(subject, parentNode);
//when
val result = parentNode.walkTree(Arrays.asList(subject, "no child"));
//then
Assert.assertThat(
assertThat(result.isPresent()).as(
"when we walk the tree to a node that doesn't exists, nothing"
+ " is found", result.isPresent(), is(false));
+ " is found").isFalse();
}
/**
* Test that when we pass null we get an exception.
*/
@Test(expected = NullPointerException.class)
@Test
public void shouldThrowNEWhenWalkTreeNull() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("path");
//when
node.walkTree(null);
}
@ -341,9 +380,11 @@ public class NodeItemTest {
@Test
public void shouldReturnEmptyForEmptyWalkTreePath() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
//when
node.walkTree(Collections.emptyList());
val result = node.walkTree(Collections.emptyList());
//then
assertThat(result).isEmpty();
}
/**
@ -352,7 +393,7 @@ public class NodeItemTest {
@Test
public void shouldCreateDescendantNodes() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val alphaData = "alpha";
val betaData = "beta";
val gammaData = "gamma";
@ -361,36 +402,34 @@ public class NodeItemTest {
Arrays.asList(alphaData, betaData, gammaData));
//then
val alphaOptional = node.getChild(alphaData);
Assert.assertThat(
"when creating a descendant line, the first element is found",
alphaOptional.isPresent(), is(true));
assertThat(alphaOptional.isPresent()).as(
"when creating a descendant line, the first element is found")
.isTrue();
if (alphaOptional.isPresent()) {
val alpha = alphaOptional.get();
Assert.assertThat(
assertThat(alpha.getParent()).as(
"when creating a descendant line, the first element has "
+ "the current node as its parent",
alpha.getParent(), is(node));
+ "the current node as its parent").isSameAs(node);
val betaOptional = alpha.getChild(betaData);
Assert.assertThat(
assertThat(betaOptional.isPresent()).as(
"when creating a descendant line, the second element is "
+ "found", betaOptional.isPresent(), is(true));
+ "found").isTrue();
if (betaOptional.isPresent()) {
val beta = betaOptional.get();
Assert.assertThat(
assertThat(beta.getParent()).as(
"when creating a descendant line, the second element "
+ "has the first as its parent",
beta.getParent(), is(alpha));
+ "has the first as its parent")
.isSameAs(alpha);
val gammaOptional = beta.getChild(gammaData);
Assert.assertThat(
assertThat(gammaOptional.isPresent()).as(
"when creating a descendant line, the third element "
+ "is found", gammaOptional.isPresent(),
is(true));
+ "is found").isTrue();
if (gammaOptional.isPresent()) {
val gamma = gammaOptional.get();
Assert.assertThat(
assertThat(gamma.getParent()).as(
"when creating a descendant line, the third "
+ "element has the second as its parent",
gamma.getParent(), is(beta));
+ "element has the second as its parent")
.isSameAs(beta);
}
}
}
@ -400,10 +439,12 @@ public class NodeItemTest {
* Test that if we pass null to create a chain of descendant nodes we get an
* exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenCreateDescendantNull() {
@Test
public void createDescendantLineShouldThrowNPEWhenDescendantsAreNull() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("descendants");
//when
node.createDescendantLine(null);
}
@ -414,13 +455,13 @@ public class NodeItemTest {
@Test
public void shouldChangeNothingWhenCreateDescendantEmpty() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
//when
node.createDescendantLine(Collections.emptyList());
//then
Assert.assertThat(
assertThat(node.getChildren()).as(
"when creating a descendant line from an empty list, nothing "
+ "is created", node.getChildren().size(), is(0));
+ "is created").isEmpty();
}
/**
@ -429,15 +470,15 @@ public class NodeItemTest {
@Test
public void shouldFindExistingChildNode() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val childData = "child";
val child = new NodeItem<String>(childData, node);
//when
val found = node.findOrCreateChild(childData);
//then
Assert.assertThat(
assertThat(found).as(
"when searching for a child by data, the matching child is "
+ "found", found, is(child));
+ "found").isSameAs(child);
}
/**
@ -446,23 +487,25 @@ public class NodeItemTest {
@Test
public void shouldFindCreateNewChildNode() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val childData = "child";
//when
val found = node.findOrCreateChild(childData);
//then
Assert.assertThat(
"when searching for a child by data, a new node is created",
found.getData(), is(childData));
assertThat(found.getData()).as(
"when searching for a child by data, a new node is created")
.isSameAs(childData);
}
/**
* Test that if we pass null we get an exception.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEFWhenFindOrCreateChildNull() {
@Test
public void findOrCreateChildShouldThrowNPEFWhenChildIsNull() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("child");
//when
node.findOrCreateChild(null);
}
@ -473,29 +516,31 @@ public class NodeItemTest {
@Test
public void shouldGetChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val childData = "child";
val child = new NodeItem<String>(childData);
val child = new NodeItem<String>(childData, Node::getData);
node.addChild(child);
//when
val found = node.getChild(childData);
//then
Assert.assertThat("when retrieving a child by its data, it is found",
found.isPresent(), is(true));
assertThat(found.isPresent()).as(
"when retrieving a child by its data, it is found").isTrue();
if (found.isPresent()) {
Assert.assertThat(
assertThat(found.get()).as(
"when retrieving a child by its data, it is the expected "
+ "node", found.get(), is(child));
+ "node").isSameAs(child);
}
}
/**
* Test that we throw an exception when passed null.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenGetChildNull() {
@Test
public void getChildShouldThrowNPEWhenThereIsNoChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("data", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("child");
//when
node.getChild(null);
}
@ -507,34 +552,330 @@ public class NodeItemTest {
@Test
public void shouldCreateChild() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
val childData = "child";
//when
val child = node.createChild(childData);
//then
Assert.assertThat(
assertThat(child.getParent()).as(
"when creating a child node, the child has the current node "
+ "as its parent", child.getParent(), is(node));
+ "as its parent").isSameAs(node);
val foundChild = node.getChild(childData);
Assert.assertThat(
assertThat(foundChild.isPresent()).as(
"when creating a child node, the child can be found by its "
+ "data", foundChild.isPresent(), is(true));
+ "data").isTrue();
if (foundChild.isPresent()) {
Assert.assertThat(
assertThat(foundChild.get()).as(
"when creating a child node, the correct child can be "
+ "found by its data", foundChild.get(), is(child));
+ "found by its data").isSameAs(child);
}
}
/**
* Test that we throw an exception when passed null.
*/
@Test(expected = NullPointerException.class)
public void shouldThrowNPEWhenCreateChildNull() {
@Test
public void createChildShouldThrowNPEWhenChildIsNull() {
//given
node = new NodeItem<>("subject");
node = new NodeItem<>("subject", Node::getData);
exception.expect(NullPointerException.class);
exception.expectMessage("child");
//when
node.createChild(null);
}
@Test
public void getNameShouldBeCorrect() {
//given
node = new NodeItem<>("subject", Node::getData);
//then
assertThat(node.getName()).isEqualTo("subject");
}
@Test
public void getNameShouldUseParentNameSupplier() {
//given
val root = new NodeItem<String>("root", Node::getData);
node = new NodeItem<>("child", root);
//then
assertThat(node.getName()).isEqualTo("child");
}
@Test
public void getNameShouldReturnNameForNonStringData() {
val root = new NodeItem<LocalDate>(LocalDate.parse("2016-05-23"),
n -> n.getData().format(DateTimeFormatter.BASIC_ISO_DATE));
//then
assertThat(root.getName()).isEqualTo("20160523");
}
@Test
public void getNameShouldUseClosestNameSupplier() {
node = new NodeItem<>("root", Node::getData);
val child = new NodeItem<String>("child", Object::toString);
node.addChild(child);
val grandChild = new NodeItem<>("grandchild", child);
//then
assertThat(node.getName()).isEqualTo("root");
assertThat(child.getName()).isNotEqualTo("child");
assertThat(grandChild.getName()).isNotEqualTo("grandchild");
}
@Test
public void getNameShouldWorkWithoutNameSupplier() {
node = new NodeItem<>(null, "root");
val namedchild = new NodeItem<>("named", "Alice", node);
//then
assertThat(node.getName()).isEqualTo("root");
assertThat(namedchild.getName()).isEqualTo("Alice");
}
@Test
public void canCreateRootNodeWithoutData() {
node = new NodeItem<>(null, "empty");
assertThat(node.getData()).isNull();
}
@Test
public void canCreateRootNodeWithoutDataButWithNameSupplier() {
node = new NodeItem<>(null, Node::getData);
assertThat(node.getData()).isNull();
}
@Test
public void getChildNamedFindsChild() {
//given
node = new NodeItem<>(null, "root");
val alpha = new NodeItem<String>(null, "alpha");
val beta = new NodeItem<String>(null, "beta");
node.addChild(alpha);
node.addChild(beta);
//when
val result = node.getChildNamed("alpha");
//then
assertThat(result).isSameAs(alpha);
}
@Test
public void getChildNamedFindsNothing() {
//given
node = new NodeItem<>(null, "root");
val alpha = new NodeItem<String>(null, "alpha");
val beta = new NodeItem<String>(null, "beta");
node.addChild(alpha);
node.addChild(beta);
exception.expect(NodeException.class);
exception.expectMessage("Named child not found");
//when
node.getChildNamed("gamma");
}
@Test
public void nodeNamesAreUniqueWithinAParent() {
//given
node = new NodeItem<>(null, "root");
val alpha = new NodeItem<String>(null, "alpha");
node.addChild(alpha);
val beta = new NodeItem<String>(null, "alpha");
exception.expect(NodeException.class);
exception.expectMessage("Node with that name already exists here");
//when
node.addChild(beta);
}
@Test
public void canPlaceNodeInTreeByPathNames() {
//given
node = new NodeItem<>(null, "root"); // create a root
val four = new NodeItem<String>("data", "four");
//when
node.placeNodeIn(four, "one", "two", "three");
//then
val three = four.getParent();
assertThat(four.getParent()).as("add node to a tree").isNotNull();
assertThat(three.getName()).isEqualTo("three");
val two = three.getParent();
assertThat(two.getName()).isEqualTo("two");
val one = two.getParent();
assertThat(one.getName()).isEqualTo("one");
assertThat(one.getParent()).isSameAs(node);
assertThat(node.getChildNamed("one")
.getChildNamed("two")
.getChildNamed("three")
.getChildNamed("four")).isSameAs(four);
}
@Test
@SuppressWarnings("unchecked")
public void canPlaceInTreeUnderExistingNode() {
//given
node = new NodeItem<>(null, "root");
val child = new NodeItem<String>("child data", "child");
val grandchild = new NodeItem<String>("grandchild data", "grandchild");
//when
node.placeNodeIn(child); // as root/child
node.placeNodeIn(grandchild, "child"); // as root/child/grandchild
//then
assertThat(node.getChildNamed("child")).as("child").isSameAs(child);
assertThat(node.getChildNamed("child").getChildNamed("grandchild")).as(
"grandchild").isSameAs(grandchild);
}
@Test
@SuppressWarnings("unchecked")
public void canPlaceInTreeAboveExistingNode() {
//given
node = new NodeItem<>(null, "root");
val child = new NodeItem<String>("child data", "child");
val grandchild = new NodeItem<String>("grandchild data", "grandchild");
//when
node.placeNodeIn(grandchild, "child");
node.placeNodeIn(child);
//then
assertThat(node.getChildNamed("child")).as("child").isSameAs(child);
assertThat(node.getChildNamed("child").getChildNamed("grandchild")).as(
"grandchild").isSameAs(grandchild);
}
@Test
public void removingParentFromNodeWithNoParentIsNoop() {
//given
node = new NodeItem<>(null);
//when
node.removeParent();
}
@Test
public void placeNodeInTreeWhereNonEmptyNodeWithSameNameExists() {
//given
exception.expect(NodeException.class);
exception.expectMessage(
"A non-empty node with that name already exists here");
node = new NodeItem<>(null);
val child = new NodeItem<String>(null, "child", node);
new NodeItem<>("data", "grandchild", child);
// root -> child -> grandchild
// only grandchild has data
//when
// attempt to add another node called 'grandchild' to 'child'
node.placeNodeIn(new NodeItem<>("cuckoo", "grandchild"), "child");
}
@Test
@SuppressWarnings("unchecked")
public void placeNodeInTreeWhenAddedNodeIsUnnamed() {
//given
node = new NodeItem<>(null);
final Node<String> newNode = new NodeItem<>(null);
//when
node.placeNodeIn(newNode);
//then
assertThat(node.getChildren()).containsOnly(newNode);
}
@Test
@SuppressWarnings("unchecked")
public void placeNodeInTreeWhenEmptyChildWithTargetNameExists() {
//given
node = new NodeItem<>(null);
final NodeItem<String> child = new NodeItem<>(null, "child");
final NodeItem<String> target = new NodeItem<>(null, "target");
node.addChild(child);
child.addChild(target);
final NodeItem<String> addMe = new NodeItem<>("I'm new", "target");
assertThat(addMe.getParent()).isNull();
//when
// addMe should replace target as the sole descendant of child
node.placeNodeIn(addMe, "child");
//then
assertThat(child.getChildren()).as("child only contains new node")
.containsOnly(addMe);
assertThat(target.getParent()).as("old node is removed from tree")
.isNull();
}
@Test
public void findChildNamedShouldThrowNPEWhenNameIsNull() {
//given
exception.expect(NullPointerException.class);
exception.expectMessage("name");
node = new NodeItem<>(null);
//when
node.findChildNamed(null);
}
@Test
public void isNamedNull() {
//given
node = new NodeItem<>(null);
//then
assertThat(node.isNamed()).isFalse();
}
@Test
public void isNamedEmpty() {
//given
node = new NodeItem<>(null, "");
//then
assertThat(node.isNamed()).isFalse();
}
@Test
public void isNamedNamed() {
//given
node = new NodeItem<>(null, "named");
//then
assertThat(node.isNamed()).isTrue();
}
@Test
public void removeParentNodeProvidesSameNameSupplier() {
// once a node has it's parent removed it should provide a default name
// provider
//given
node = new NodeItem<>("data", Node::getData); // name provider: getData
final NodeItem<String> child = new NodeItem<>("other", node);
assertThat(node.getName()).as("initial root name").isEqualTo("data");
assertThat(child.getName()).as("initial child name").isEqualTo("other");
//when
child.removeParent();
//then
assertThat(node.getName()).as("final root name").isEqualTo("data");
assertThat(child.getName()).as("final child name").isEqualTo("other");
}
@Test
@SuppressWarnings("unchecked")
public void removeChildRemovesTheChild() {
//given
node = new NodeItem<>(null);
Node<String> child = node.createChild("child");
assertThat(node.getChildren()).containsExactly(child);
//then
node.removeChild(child);
//then
assertThat(node.getChildren()).isEmpty();
}
@Test
public void drawTreeIsCorrect() {
//given
node = new NodeItem<>(null, "root");
val bob = new NodeItem<String>(null, "bob", node);
val alice = new NodeItem<String>(null, "alice", node);
new NodeItem<>(null, "dave", alice);
new NodeItem<>(null, bob); // has no name and no children so no included
val kim = new NodeItem<String>(null, node); // nameless mother
new NodeItem<>(null, "lucy", kim);
//when
val tree = node.drawTree(0);
//then
String[] lines = tree.split("\n");
assertThat(lines).contains("[root]", "[ alice]", "[ dave]",
"[ (unnamed)]", "[ lucy]", "[ bob]");
assertThat(lines).containsSubsequence("[root]", "[ alice]", "[ dave]");
assertThat(lines).containsSubsequence("[root]", "[ (unnamed)]",
"[ lucy]");
assertThat(lines).containsSubsequence("[root]", "[ bob]");
}
}