Implemented new tree abstraction

1 files changed, 235 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java b/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java
new file mode 100644
index 0000000..d9938d4
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java
@@ -0,0 +1,235 @@
+package bjc.utils.funcdata;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.UnaryOperator;
+
+import bjc.utils.funcdata.bst.TreeLinearizationMethod;
+
+/**
+ * A node in a homogenous tree.
+ * 
+ * @author ben
+ *
+ * @param <ContainedType>
+ */
+public class Tree<ContainedType> implements ITree<ContainedType> {
+	private ContainedType							data;
+	private IFunctionalList<ITree<ContainedType>>	children;
+
+	private boolean									hasChildren;
+
+	private int										childCount;
+
+	/**
+	 * Create a new leaf node in a tree
+	 * 
+	 * @param leafToken
+	 *            The data to store as a leaf node
+	 */
+	public Tree(ContainedType leafToken) {
+		data = leafToken;
+
+		hasChildren = false;
+	}
+
+	/**
+	 * Create a new tree node with the specified children
+	 * 
+	 * @param leafToken
+	 *            The data to hold in this node
+	 * @param childrn
+	 *            A list of children for this node
+	 */
+	@SafeVarargs
+	public Tree(ContainedType leafToken, ITree<ContainedType>... childrn) {
+		data = leafToken;
+
+		hasChildren = true;
+
+		childCount = 0;
+
+		children = new FunctionalList<>();
+
+		for (ITree<ContainedType> child : childrn) {
+			children.add(child);
+
+			childCount++;
+		}
+	}
+
+	private Tree(ContainedType leafToken,
+			IFunctionalList<ITree<ContainedType>> childrn) {
+		data = leafToken;
+
+		hasChildren = true;
+
+		childCount = childrn.getSize();
+
+		children = childrn;
+	}
+
+	@Override
+	public void addChild(ITree<ContainedType> child) {
+		if (hasChildren == false) {
+			hasChildren = true;
+
+			children = new FunctionalList<>();
+		}
+
+		childCount++;
+
+		children.add(child);
+	}
+
+	@Override
+	public <TransformedType> TransformedType transformHead(
+			Function<ContainedType, TransformedType> transformer) {
+		return transformer.apply(data);
+	}
+
+	@Override
+	public int getChildrenCount() {
+		return childCount;
+	}
+
+	@Override
+	public <TransformedType> TransformedType transformChild(int childNo,
+			Function<ITree<ContainedType>, TransformedType> transformer) {
+		if (childNo < 0 || childNo > (childCount - 1)) {
+			throw new IllegalArgumentException(
+					"Child index #" + childNo + " is invalid");
+		}
+
+		return transformer.apply(children.getByIndex(childNo));
+	}
+
+	@Override
+	public <NewType, ReturnedType> ReturnedType collapse(
+			Function<ContainedType, NewType> leafTransform,
+			Function<ContainedType, Function<IFunctionalList<NewType>, NewType>> nodeCollapser,
+			Function<NewType, ReturnedType> resultTransformer) {
+
+		return resultTransformer
+				.apply(internalCollapse(leafTransform, nodeCollapser));
+	}
+
+	protected <NewType> NewType internalCollapse(
+			Function<ContainedType, NewType> leafTransform,
+			Function<ContainedType, Function<IFunctionalList<NewType>, NewType>> nodeCollapser) {
+		if (hasChildren) {
+			Function<IFunctionalList<NewType>, NewType> nodeTransformer = nodeCollapser
+					.apply(data);
+
+			IFunctionalList<NewType> collapsedChildren = children
+					.map((child) -> {
+						return child.collapse(leafTransform, nodeCollapser,
+								(subTreeVal) -> subTreeVal);
+					});
+
+			return nodeTransformer.apply(collapsedChildren);
+		}
+
+		return leafTransform.apply(data);
+	}
+
+	@Override
+	public ITree<ContainedType> flatMapTree(
+			Function<ContainedType, ITree<ContainedType>> mapper) {
+		if (hasChildren) {
+			ITree<ContainedType> flatMappedData = mapper.apply(data);
+
+			children.map((child) -> child.flatMapTree(mapper))
+					.forEach((child) -> flatMappedData.addChild(child));
+
+			return flatMappedData;
+		}
+
+		return mapper.apply(data);
+	}
+
+	@Override
+	public void selectiveTransform(Predicate<ContainedType> nodePicker,
+			UnaryOperator<ContainedType> transformer) {
+		if (hasChildren) {
+			children.forEach((child) -> child
+					.selectiveTransform(nodePicker, transformer));
+		} else {
+			data = transformer.apply(data);
+		}
+	}
+
+	@Override
+	public <MappedType> ITree<MappedType> transformTree(
+			Function<ContainedType, MappedType> transformer) {
+		if (hasChildren) {
+			IFunctionalList<ITree<MappedType>> transformedChildren = children
+					.map((child) -> child.transformTree(transformer));
+
+			return new Tree<>(transformer.apply(data),
+					transformedChildren);
+		}
+
+		return new Tree<>(transformer.apply(data));
+	}
+
+	@Override
+	public void traverse(TreeLinearizationMethod linearizationMethod,
+			Consumer<ContainedType> action) {
+		if (hasChildren) {
+			switch (linearizationMethod) {
+				case INORDER:
+					if (childCount != 2) {
+						throw new IllegalArgumentException(
+								"Can only do in-order traversal for binary trees.");
+					}
+
+					children.getByIndex(0).traverse(linearizationMethod,
+							action);
+
+					action.accept(data);
+
+					children.getByIndex(1).traverse(linearizationMethod,
+							action);
+					break;
+				case POSTORDER:
+					children.forEach((child) -> child
+							.traverse(linearizationMethod, action));
+
+					action.accept(data);
+					break;
+				case PREORDER:
+					action.accept(data);
+
+					children.forEach((child) -> child
+							.traverse(linearizationMethod, action));
+					break;
+				default:
+					break;
+
+			}
+		} else {
+			action.accept(data);
+		}
+	}
+
+	@Override
+	public <MappedType> ITree<MappedType> rebuildTree(
+			Function<ContainedType, MappedType> leafTransformer,
+			Function<ContainedType, MappedType> operatorTransformer) {
+		if (hasChildren) {
+			IFunctionalList<ITree<MappedType>> mappedChildren = children
+					.map((child) -> {
+						return child.rebuildTree(leafTransformer,
+								operatorTransformer);
+					});
+
+			return new Tree<>(operatorTransformer.apply(data),
+					mappedChildren);
+		}
+
+		return new Tree<>(leafTransformer.apply(data));
+	}
+
+}