AbstractNodeItem: added

This commit is contained in:
Paul Campbell 2016-08-21 19:08:59 +01:00
parent cf6bc72717
commit be0685538f

View file

@ -0,0 +1,157 @@
package net.kemitix.node;
import java.util.HashSet;
import java.util.List;
import java.util.Optional;
import java.util.Set;
/**
* An abstract node item, providing default implementations for most read-only
* operations.
*
* @param <T> the type of data stored in each node
*
* @author pcampbell
*/
abstract class AbstractNodeItem<T> implements Node<T> {
private T data;
private String name;
private Node<T> parent;
private final Set<Node<T>> children;
protected AbstractNodeItem(
final T data, final String name, final Node<T> parent,
final Set<Node<T>> children) {
this.data = data;
this.name = name;
this.parent = parent;
this.children = children;
}
@Override
public String getName() {
return name;
}
@Override
public Optional<T> getData() {
return Optional.ofNullable(data);
}
@Override
public boolean isEmpty() {
return data == null;
}
@Override
public Optional<Node<T>> getParent() {
return Optional.ofNullable(parent);
}
@Override
public Set<Node<T>> getChildren() {
return new HashSet<>(children);
}
/**
* 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>> findChild(final T child) {
if (child == null) {
throw new NullPointerException("child");
}
return children.stream().filter(node -> {
final Optional<T> d = node.getData();
return d.isPresent() && d.get().equals(child);
}).findAny();
}
@Override
public Node<T> getChild(final T child) {
return findChild(child).orElseThrow(
() -> new NodeException("Child not found"));
}
/**
* Checks if the node is an ancestor.
*
* @param node the potential ancestor
*
* @return true if the node is an ancestor
*/
@Override
public boolean isDescendantOf(final Node<T> node) {
return parent != null && (node.equals(parent) || parent.isDescendantOf(
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>> findInPath(final List<T> path) {
if (path == null) {
throw new NullPointerException("path");
}
if (path.size() > 0) {
Optional<Node<T>> found = findChild(path.get(0));
if (found.isPresent()) {
if (path.size() > 1) {
return found.get().findInPath(path.subList(1, path.size()));
}
return found;
}
}
return Optional.empty();
}
@Override
public Optional<Node<T>> findChildByName(final String named) {
if (named == null) {
throw new NullPointerException("name");
}
return children.stream()
.filter(n -> n.getName().equals(named))
.findAny();
}
@Override
public Node<T> getChildByName(final String named) {
return findChildByName(named).orElseThrow(
() -> 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().forEach(c -> sb.append(c.drawTree(depth + 1)));
return sb.toString();
}
@Override
public boolean isNamed() {
return name != null && name.length() > 0;
}
}