From 0085d120b4140b489b90942336a3328b364f6f6e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mariusz=20Smyku=C5=82a?= <mariuszs@gmail.com>
Date: Sun, 10 Feb 2019 03:29:26 +0100
Subject: [PATCH] lazy streams with pager spliterator (#295) (#296)

---
 src/main/java/org/gitlab4j/api/Pager.java     |  9 ++++
 .../org/gitlab4j/api/PagerSpliterator.java    | 47 +++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/main/java/org/gitlab4j/api/PagerSpliterator.java

diff --git a/src/main/java/org/gitlab4j/api/Pager.java b/src/main/java/org/gitlab4j/api/Pager.java
index 70f790c2..bb73d651 100644
--- a/src/main/java/org/gitlab4j/api/Pager.java
+++ b/src/main/java/org/gitlab4j/api/Pager.java
@@ -7,6 +7,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.core.Response;
@@ -333,4 +334,12 @@ public class Pager<T> implements Iterator<List<T>>, Constants {
 
     	return (streamBuilder.build());
     }
+
+    public Stream<T> lazyStream() {
+        // Make sure that current page is 0, this will ensure the whole list is streamed
+        // regardless of what page the instance is currently on.
+        currentPage = 0;
+
+        return StreamSupport.stream(new PagerSpliterator<T>(this), false);
+    }
 }
diff --git a/src/main/java/org/gitlab4j/api/PagerSpliterator.java b/src/main/java/org/gitlab4j/api/PagerSpliterator.java
new file mode 100644
index 00000000..94337312
--- /dev/null
+++ b/src/main/java/org/gitlab4j/api/PagerSpliterator.java
@@ -0,0 +1,47 @@
+package org.gitlab4j.api;
+
+import java.util.Iterator;
+import java.util.Spliterator;
+import java.util.function.Consumer;
+
+class PagerSpliterator<T> implements Spliterator<T> {
+
+	private Pager<T> pager;
+
+	private Iterator<T> elements;
+
+	PagerSpliterator(Pager<T> pager) {
+		this.pager = pager;
+		if (pager.hasNext()) {
+			elements = this.pager.next().iterator();
+		}
+	}
+
+	@Override
+	public boolean tryAdvance(Consumer<? super T> action) {
+		if (elements.hasNext()) {
+			action.accept(elements.next());
+			return true;
+		} else if (pager.hasNext()) {
+			elements = pager.next().iterator();
+			action.accept(elements.next());
+			return true;
+		}
+		return false;
+	}
+
+	@Override
+	public Spliterator<T> trySplit() {
+		return null;
+	}
+
+	@Override
+	public long estimateSize() {
+		return pager.getTotalItems();
+	}
+
+	@Override
+	public int characteristics() {
+		return 0;
+	}
+}
-- 
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