Added Java 8 stream support.

Author: gmessner

README.md

@@ -11,7 +11,7 @@ To utilize the GitLab API for Java in your project, simply add the following dep
 ```java
 dependencies {
     ...
-    compile group: 'org.gitlab4j', name: 'gitlab4j-api', version: '4.9.1'
+    compile group: 'org.gitlab4j', name: 'gitlab4j-api', version: '4.9.2'
 }
 ```
 
@@ -22,7 +22,7 @@ dependencies {
 <dependency>
     <groupId>org.gitlab4j</groupId>
     <artifactId>gitlab4j-api</artifactId>
-    <version>4.9.1</version>
+    <version>4.9.2</version>
 </dependency>
 ```
 
@@ -130,6 +130,21 @@ while (projectsPager.hasNext())) {
     }
 }
 ```
+As of GitLab4J-API 4.9.2, you can also fetch all the items as a single list or get a Java 8+ Stream instance using a Pager instance:
+```java
+// Get a Pager instance so we can load all the projects into a single list, 10 items at a time:
+Pager<Project> projectPager = gitlabApi.getProjectsApi().getProjects(10);
+List<Project> allProjects = projectPager.all();
+```
+
+```java
+// Get a Pager instance to get a Stream<Project> instance.
+Pager<Project> projectPager = gitlabApi.getProjectsApi().getProjects(10);
+
+// Stream the Projects printing out the project name.
+projectPager.stream().map(Project::getName).forEach(name -> System.out.println(name));
+```
+
 ---
 ## Java 8 Optional&lt;T&gt; Support
 GitLab4J-API supports Java 8 Optional&lt;T&gt; for API calls that result in the return of a single item. Here is an example on how to use the Java 8 Optional&lt;T&gt; API calls:

src/main/java/org/gitlab4j/api/Pager.java

@@ -3,9 +3,11 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.stream.Stream;
 
 import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.core.Response;
@@ -274,4 +276,49 @@ public List<T> page(int pageNumber) {
             throw new RuntimeException(e);
         }
     }
+ 
+    /**
+     * Gets all the items from each page as a single List instance.
+     *
+     * @return all the items from each page as a single List instance
+     * @throws GitLabApiException if any error occurs
+     */
+    public List<T> all() throws GitLabApiException {
+
+    	// Make sure that current page is 0, this will ensure the whole list is fetched
+    	// regardless of what page the instance is currently on.
+    	currentPage = 0;
+    	List<T> allItems = new ArrayList<>(totalItems);
+
+    	// Iterate through the pages and append each page of items to the list
+    	while (hasNext()) {
+    		allItems.addAll(next());
+    	}
+
+    	return (allItems);
+    }
+
+    /**
+     * Builds and returns a Stream instance for streaming all the items from each page.
+     *
+     * @return a Stream instance for streaming all the items from each pag
+     * @throws GitLabApiException if any error occurs
+     */
+    public Stream<T> stream() throws GitLabApiException {
+
+    	// 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;
+
+    	// Create a Stream.Builder to ontain all the items.  This is more efficient than
+    	// getting a List with all() and streaming that List
+    	Stream.Builder<T> streamBuilder = Stream.builder();
+
+    	// Iterate through the pages and append each page of items to the stream builder
+    	while (hasNext()) {
+    		next().forEach(streamBuilder);
+    	}
+
+    	return (streamBuilder.build());
+    }
 }

src/test/java/org/gitlab4j/api/TestPager.java

@@ -9,6 +9,7 @@
 
 import org.gitlab4j.api.GitLabApi.ApiVersion;
 import org.gitlab4j.api.models.Branch;
+import org.gitlab4j.api.models.Commit;
 import org.gitlab4j.api.models.Member;
 import org.gitlab4j.api.models.Project;
 import org.junit.Before;
@@ -200,4 +201,43 @@ public void testMembersPager() throws GitLabApiException {
             }
         }
     }
+
+    @Test
+    public void testAll() throws GitLabApiException {
+
+        Project project = gitLabApi.getProjectApi().getProject(TEST_NAMESPACE, TEST_PROJECT_NAME);
+        assertNotNull(project);
+
+        Pager<Commit> pager = gitLabApi.getCommitsApi().getCommits(project, 1);
+        assertNotNull(pager);
+        assertEquals(1, pager.getItemsPerPage());
+        assertTrue(0 < pager.getTotalPages());
+
+        int numCommits = pager.getTotalItems();
+        assertTrue(0 < numCommits);
+
+        List<Commit> allCommits = pager.all();
+        System.out.println("All commits:");
+        allCommits.stream().map(Commit::getId).forEach(System.out::println);
+
+        assertEquals(numCommits, allCommits.size());
+    }
+
+    @Test
+    public void testStream() throws GitLabApiException {
+
+        Project project = gitLabApi.getProjectApi().getProject(TEST_NAMESPACE, TEST_PROJECT_NAME);
+        assertNotNull(project);
+
+        Pager<Commit> pager = gitLabApi.getCommitsApi().getCommits(project, 1);
+        assertNotNull(pager);
+        assertEquals(1, pager.getItemsPerPage());
+        assertTrue(0 < pager.getTotalPages());
+
+        int numCommits = pager.getTotalItems();
+        assertTrue(0 < numCommits);
+
+        System.out.println("Streamed commits:");
+       assertEquals(numCommits, pager.stream().map(Commit::getId).peek(System.out::println).count());
+    }
 }