This is an automated email from the ASF dual-hosted git repository.
ahuber pushed a commit to branch dev/2.0.0/ISIS-898-treeview
in repository https://gitbox.apache.org/repos/asf/isis.git
commit d337130decc55615a92e7272b5c0100fe6d36bac
Author: Andi Huber <ahu...@apache.org>
AuthorDate: Sat Apr 14 09:13:34 2018 +0200
ISIS-898 applib: introduces initial tree model
---
.../org/apache/isis/applib/tree/TreeAdapter.java | 14 ++++
.../java/org/apache/isis/applib/tree/TreeNode.java | 80 ++++++++++++++++++++++
.../org/apache/isis/applib/tree/TreeNode_Lazy.java | 57 +++++++++++++++
.../applib/tree/TreeNode_iteratorBreadthFirst.java | 42 ++++++++++++
.../applib/tree/TreeNode_iteratorDepthFirst.java | 53 ++++++++++++++
.../applib/tree/TreeNode_iteratorHierarchyUp.java | 35 ++++++++++
6 files changed, 281 insertions(+)
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeAdapter.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeAdapter.java
new file mode 100644
index 0000000..5c39b59
--- /dev/null
+++ b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeAdapter.java
@@ -0,0 +1,14 @@
+package org.apache.isis.applib.tree;
+
+import java.util.Optional;
+import java.util.stream.Stream;
+
+public interface TreeAdapter<T> {
+
+ public Optional<T> parentOf(T value);
+
+ public int childCountOf(T value);
+
+ public Stream<T> childrenOf(T value);
+
+}
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode.java
new file mode 100644
index 0000000..f8f6fc4
--- /dev/null
+++ b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode.java
@@ -0,0 +1,80 @@
+package org.apache.isis.applib.tree;
+
+import java.util.Iterator;
+import java.util.Optional;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+public interface TreeNode<T> {
+
+ // -- VALUE
+
+ public T getValue();
+
+ // -- PARENT
+
+ public Optional<TreeNode<T>> getParent();
+
+ // -- CHILDREN
+
+ public int getChildCount();
+
+ public Stream<TreeNode<T>> streamChildren();
+
+ // -- BASIC PREDICATES
+
+ public default boolean isRoot() {
+ return !getParent().isPresent();
+ }
+
+ public default boolean isLeaf() {
+ return getChildCount() == 0;
+ }
+
+ // -- CONSTRUCTION
+
+ public static <T> TreeNode<T> of(T node, TreeAdapter<T> treeAdapter) {
+ return TreeNode_Lazy.of(node, treeAdapter);
+ }
+
+ // -- PARENT NODE ITERATION
+
+ public default Iterator<TreeNode<T>> iteratorHierarchyUp(){
+ return new TreeNode_iteratorHierarchyUp<>(this);
+ }
+
+ // -- PARENT NODE STREAMING
+
+ public default Stream<TreeNode<T>> streamHierarchyUp(){
+ return StreamSupport.stream(
+
Spliterators.spliteratorUnknownSize(iteratorHierarchyUp(),
Spliterator.ORDERED),
+ false); // not parallel
+ }
+
+ // -- CHILD NODE ITERATION
+
+ public default Iterator<TreeNode<T>> iteratorDepthFirst(){
+ return new TreeNode_iteratorDepthFirst<>(this);
+ }
+
+ public default Iterator<TreeNode<T>> iteratorBreadthFirst(){
+ return new TreeNode_iteratorBreadthFirst<>(this);
+ }
+
+ // -- CHILD NODE STREAMING
+
+ public default Stream<TreeNode<T>> streamDepthFirst(){
+ return StreamSupport.stream(
+
Spliterators.spliteratorUnknownSize(iteratorDepthFirst(), Spliterator.ORDERED),
+ false); // not parallel
+ }
+
+ public default Stream<TreeNode<T>> streamBreadthFirst(){
+ return StreamSupport.stream(
+
Spliterators.spliteratorUnknownSize(iteratorBreadthFirst(),
Spliterator.ORDERED),
+ false); // not parallel
+ }
+
+}
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_Lazy.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_Lazy.java
new file mode 100644
index 0000000..83cd503
--- /dev/null
+++ b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_Lazy.java
@@ -0,0 +1,57 @@
+package org.apache.isis.applib.tree;
+
+import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Stream;
+
+class TreeNode_Lazy<T> implements TreeNode<T> {
+
+ private final T value;
+ private final TreeAdapter<T> treeAdapter;
+
+ static <T> TreeNode_Lazy<T> of(T value, TreeAdapter<T> treeAdapter) {
+ Objects.requireNonNull(value);
+ Objects.requireNonNull(treeAdapter);
+ return new TreeNode_Lazy<T>(value, treeAdapter);
+ }
+
+ private TreeNode_Lazy(T value, TreeAdapter<T> treeAdapter) {
+ this.value = value;
+ this.treeAdapter = treeAdapter;
+ }
+
+ @Override
+ public T getValue() {
+ return value;
+ }
+
+ @Override
+ public Optional<TreeNode<T>> getParent() {
+ return treeAdapter.parentOf(getValue())
+ .map(this::toTreeNode)
+ ;
+ }
+
+ @Override
+ public int getChildCount() {
+ return treeAdapter.childCountOf(value);
+ }
+
+ @Override
+ public Stream<TreeNode<T>> streamChildren() {
+ if(isLeaf()) {
+ return Stream.empty();
+ }
+ return treeAdapter.childrenOf(value)
+ .map(this::toTreeNode)
+ ;
+ }
+
+ // -- HELPER
+
+ private TreeNode<T> toTreeNode(T value){
+ return of(value, treeAdapter);
+ }
+
+
+}
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorBreadthFirst.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorBreadthFirst.java
new file mode 100644
index 0000000..4f620c2
--- /dev/null
+++
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorBreadthFirst.java
@@ -0,0 +1,42 @@
+package org.apache.isis.applib.tree;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+class TreeNode_iteratorBreadthFirst<T> implements Iterator<TreeNode<T>> {
+
+ private Deque<TreeNode<T>> deque = new ArrayDeque<>();
+ private TreeNode<T> next;
+
+ TreeNode_iteratorBreadthFirst(TreeNode<T> treeNode) {
+ next = treeNode;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return next!=null;
+ }
+
+ @Override
+ public TreeNode<T> next() {
+ if(next==null) {
+ throw new NoSuchElementException("Iterator has run out
of elements.");
+ }
+ final TreeNode<T> result = next;
+ next = fetchNext(next);
+ return result;
+ }
+
+ // -- HELPER
+
+ private TreeNode<T> fetchNext(TreeNode<T> current) {
+ if(!current.isLeaf()) {
+ current.streamChildren()
+ .forEach(deque::offerLast);
+ }
+ return deque.pollFirst();
+ }
+
+}
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorDepthFirst.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorDepthFirst.java
new file mode 100644
index 0000000..a9f63d3
--- /dev/null
+++
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorDepthFirst.java
@@ -0,0 +1,53 @@
+package org.apache.isis.applib.tree;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Stack;
+
+class TreeNode_iteratorDepthFirst<T> implements Iterator<TreeNode<T>> {
+
+ private Stack<TreeNode<T>> stack = new Stack<>();
+ private TreeNode<T> next;
+
+ TreeNode_iteratorDepthFirst(TreeNode<T> treeNode) {
+ next = treeNode;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return next!=null;
+ }
+
+ @Override
+ public TreeNode<T> next() {
+ if(next==null) {
+ throw new NoSuchElementException("Iterator has run out
of elements.");
+ }
+ final TreeNode<T> result = next;
+ next = fetchNext(next);
+ return result;
+ }
+
+ // -- HELPER
+
+ private TreeNode<T> fetchNext(TreeNode<T> current) {
+ if(!current.isLeaf()) {
+ pushChildrenToStackInReverseOrder(current);
+ }
+ return stack.isEmpty() ? null : stack.pop();
+ }
+
+ private Stack<TreeNode<T>> fifo = new Stack<>(); // declared as field
only to reduce heap pollution
+
+ private void pushChildrenToStackInReverseOrder(TreeNode<T> node) {
+
+ node.streamChildren()
+ .forEach(fifo::push);
+
+ while(!fifo.isEmpty()) {
+ stack.push(fifo.pop());
+ }
+ }
+
+
+}
diff --git
a/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorHierarchyUp.java
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorHierarchyUp.java
new file mode 100644
index 0000000..62813b2
--- /dev/null
+++
b/core/applib/src/main/java/org/apache/isis/applib/tree/TreeNode_iteratorHierarchyUp.java
@@ -0,0 +1,35 @@
+package org.apache.isis.applib.tree;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+class TreeNode_iteratorHierarchyUp<T> implements Iterator<TreeNode<T>> {
+
+ private TreeNode<T> next;
+
+ TreeNode_iteratorHierarchyUp(TreeNode<T> treeNode) {
+ next = treeNode;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return next!=null;
+ }
+
+ @Override
+ public TreeNode<T> next() {
+ if(next==null) {
+ throw new NoSuchElementException("Iterator has run out
of elements.");
+ }
+ final TreeNode<T> result = next;
+ next = fetchNext(next);
+ return result;
+ }
+
+ // -- HELPER
+
+ private TreeNode<T> fetchNext(TreeNode<T> current) {
+ return current.getParent().orElse(null);
+ }
+
+}
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