From 5000dbf789bf591b363f023001b09404d2038a7d Mon Sep 17 00:00:00 2001
From: Ratan Rai Sur <ratan.r.sur@gmail.com>
Date: Mon, 15 Jul 2019 16:41:15 -0400
Subject: [PATCH] change getChildren return type (#1674)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>
---
 .../tech/pegasys/pantheon/ethereum/trie/BranchNode.java     | 4 ++--
 .../tech/pegasys/pantheon/ethereum/trie/ExtensionNode.java  | 4 ++--
 .../java/tech/pegasys/pantheon/ethereum/trie/LeafNode.java  | 5 +++--
 .../main/java/tech/pegasys/pantheon/ethereum/trie/Node.java | 2 +-
 .../java/tech/pegasys/pantheon/ethereum/trie/NullNode.java  | 5 +++--
 .../tech/pegasys/pantheon/ethereum/trie/StoredNode.java     | 2 +-
 .../pegasys/pantheon/ethereum/trie/TrieNodeDecoder.java     | 6 +++---
 .../pegasys/pantheon/ethereum/trie/TrieNodeDecoderTest.java | 2 +-
 8 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/BranchNode.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/BranchNode.java
index 2899d4a14d..371941f697 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/BranchNode.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/BranchNode.java
@@ -76,8 +76,8 @@ class BranchNode<V> implements Node<V> {
   }
 
   @Override
-  public Optional<List<Node<V>>> getChildren() {
-    return Optional.of(Collections.unmodifiableList(children));
+  public List<Node<V>> getChildren() {
+    return Collections.unmodifiableList(children);
   }
 
   public Node<V> child(final byte index) {
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/ExtensionNode.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/ExtensionNode.java
index 41c0909581..32566cb473 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/ExtensionNode.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/ExtensionNode.java
@@ -64,8 +64,8 @@ class ExtensionNode<V> implements Node<V> {
   }
 
   @Override
-  public Optional<List<Node<V>>> getChildren() {
-    return Optional.of(Collections.singletonList(child));
+  public List<Node<V>> getChildren() {
+    return Collections.singletonList(child);
   }
 
   public Node<V> getChild() {
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/LeafNode.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/LeafNode.java
index 45e72e6923..c91a21ac04 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/LeafNode.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/LeafNode.java
@@ -21,6 +21,7 @@ import tech.pegasys.pantheon.util.bytes.BytesValue;
 
 import java.lang.ref.SoftReference;
 import java.lang.ref.WeakReference;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.function.Function;
@@ -66,8 +67,8 @@ class LeafNode<V> implements Node<V> {
   }
 
   @Override
-  public Optional<List<Node<V>>> getChildren() {
-    return Optional.empty();
+  public List<Node<V>> getChildren() {
+    return Collections.emptyList();
   }
 
   @Override
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/Node.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/Node.java
index 8f35692d20..e24eaaa4b5 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/Node.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/Node.java
@@ -28,7 +28,7 @@ public interface Node<V> {
 
   Optional<V> getValue();
 
-  Optional<List<Node<V>>> getChildren();
+  List<Node<V>> getChildren();
 
   BytesValue getRlp();
 
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/NullNode.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/NullNode.java
index e6996facab..15f388d16d 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/NullNode.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/NullNode.java
@@ -15,6 +15,7 @@ package tech.pegasys.pantheon.ethereum.trie;
 import tech.pegasys.pantheon.util.bytes.Bytes32;
 import tech.pegasys.pantheon.util.bytes.BytesValue;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -50,8 +51,8 @@ class NullNode<V> implements Node<V> {
   }
 
   @Override
-  public Optional<List<Node<V>>> getChildren() {
-    return Optional.empty();
+  public List<Node<V>> getChildren() {
+    return Collections.emptyList();
   }
 
   @Override
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/StoredNode.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/StoredNode.java
index a9b0759829..6b409aba23 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/StoredNode.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/StoredNode.java
@@ -65,7 +65,7 @@ class StoredNode<V> implements Node<V> {
   }
 
   @Override
-  public Optional<List<Node<V>>> getChildren() {
+  public List<Node<V>> getChildren() {
     return load().getChildren();
   }
 
diff --git a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoder.java b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoder.java
index 92e9525a66..5212e90df0 100644
--- a/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoder.java
+++ b/ethereum/trie/src/main/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoder.java
@@ -57,7 +57,7 @@ public class TrieNodeDecoder {
     nodes.add(node);
 
     final List<Node<BytesValue>> toProcess = new ArrayList<>();
-    node.getChildren().ifPresent(toProcess::addAll);
+    toProcess.addAll(node.getChildren());
     while (!toProcess.isEmpty()) {
       final Node<BytesValue> currentNode = toProcess.remove(0);
       if (Objects.equals(NullNode.instance(), currentNode)) {
@@ -68,7 +68,7 @@ public class TrieNodeDecoder {
 
       if (!currentNode.isReferencedByHash()) {
         // If current node is inlined, that means we can process its children
-        currentNode.getChildren().ifPresent(toProcess::addAll);
+        toProcess.addAll(currentNode.getChildren());
       }
     }
 
@@ -140,7 +140,7 @@ public class TrieNodeDecoder {
       final Node<BytesValue> nextNode = currentNodes.remove(0);
 
       final List<Node<BytesValue>> children = new ArrayList<>();
-      nextNode.getChildren().ifPresent(children::addAll);
+      children.addAll(nextNode.getChildren());
       while (!children.isEmpty()) {
         Node<BytesValue> child = children.remove(0);
         if (Objects.equals(child, NullNode.instance())) {
diff --git a/ethereum/trie/src/test/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoderTest.java b/ethereum/trie/src/test/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoderTest.java
index 4feb18eb03..1361722cdb 100644
--- a/ethereum/trie/src/test/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoderTest.java
+++ b/ethereum/trie/src/test/java/tech/pegasys/pantheon/ethereum/trie/TrieNodeDecoderTest.java
@@ -114,7 +114,7 @@ public class TrieNodeDecoderTest {
     assertThat(depth0And1Nodes.get(0).getHash()).isEqualTo(rootNode.getHash());
     // Subsequent nodes should be children of root node
     List<Bytes32> expectedNodesHashes =
-        rootNode.getChildren().get().stream()
+        rootNode.getChildren().stream()
             .filter(n -> !Objects.equals(n, NullNode.instance()))
             .map(Node::getHash)
             .collect(Collectors.toList());