Add AddCommand #addFilepatterns methods

for varargs and collection arguments to facilitate adding multiple
patterns in a single API call.

Bug: jgit-247
Change-Id: I162eacea891d45a6e8feb7d0f6b66f8addfed78f

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java
index 2266772..0d87109 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/AddCommandTest.java
@@ -27,6 +27,7 @@
 import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.nio.file.Files;
+import java.util.List;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
@@ -110,6 +111,46 @@ public void testAddExistingSingleFile() throws IOException, GitAPIException {
 	}
 
 	@Test
+	public void testAddExistingMultipleFiles()
+			throws IOException, GitAPIException {
+		File file = new File(db.getWorkTree(), "a.txt");
+		FileUtils.createNewFile(file);
+		file = new File(db.getWorkTree(), "b.txt");
+		FileUtils.createNewFile(file);
+		try (PrintWriter writer = new PrintWriter(file, UTF_8.name())) {
+			writer.print("content");
+		}
+
+		try (Git git = new Git(db)) {
+			git.add().addFilepatterns("a.txt", "b.txt").call();
+
+			assertEquals(
+					"[a.txt, mode:100644, content:][b.txt, mode:100644, content:content]",
+					indexState(CONTENT));
+		}
+	}
+
+	@Test
+	public void testAddExistingMultipleFilesCollection()
+			throws IOException, GitAPIException {
+		File file = new File(db.getWorkTree(), "a.txt");
+		FileUtils.createNewFile(file);
+		file = new File(db.getWorkTree(), "b.txt");
+		FileUtils.createNewFile(file);
+		try (PrintWriter writer = new PrintWriter(file, UTF_8.name())) {
+			writer.print("content");
+		}
+
+		try (Git git = new Git(db)) {
+			git.add().addFilepatterns(List.of("a.txt", "b.txt")).call();
+
+			assertEquals(
+					"[a.txt, mode:100644, content:][b.txt, mode:100644, content:content]",
+					indexState(CONTENT));
+		}
+	}
+
+	@Test
 	public void testAddLink() throws IOException, GitAPIException {
 		assumeTrue(db.getFS().supportsSymlinks());
 		try (Git git = new Git(db)) {

org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
index b4d1cab..23bda6f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
@@ -20,7 +20,9 @@
 import java.text.MessageFormat;
 import java.time.Instant;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 
 import org.eclipse.jgit.api.errors.FilterFailedException;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -114,6 +116,36 @@ public AddCommand addFilepattern(String filepattern) {
 	}
 
 	/**
+	 * Add paths to a file/directory whose content should be added.
+	 *
+	 * @param patterns
+	 *            repository-relative paths of file/directory to add (with
+	 *            <code>/</code> as separator)
+	 * @return {@code this}
+	 * @since 7.6
+	 */
+	public AddCommand addFilepatterns(String... patterns) {
+		List.of(Objects.requireNonNull(patterns)).forEach(this::addFilepattern);
+		return this;
+	}
+
+	/**
+	 * Add paths to a file/directory whose content should be added.
+	 *
+	 * @param patterns
+	 *            repository-relative paths of file/directory to add (with
+	 *            <code>/</code> as separator)
+	 * @return {@code this}
+	 * @since 7.6
+	 */
+	public AddCommand addFilepatterns(Collection<String> patterns) {
+		if (patterns != null) {
+			patterns.forEach(this::addFilepattern);
+		}
+		return this;
+	}
+
+	/**
 	 * Allow clients to provide their own implementation of a FileTreeIterator
 	 *
 	 * @param f