Add FetchCommand#setRefSpecs(String...) variant

Much of the time the caller can specify a RefSpec succinctly using a
string, and doesn't care about calling setters. Add a convenience method
for this case, and use it where applicable in JGit core.

Change-Id: Ic3fac7fc568eee4759236a5264d2e7e5f9b9716d

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

@@ -85,7 +85,6 @@ import org.eclipse.jgit.lib.Sets;
 import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
-import org.eclipse.jgit.transport.RefSpec;
 import org.eclipse.jgit.transport.RemoteConfig;
 import org.eclipse.jgit.transport.URIish;
 import org.eclipse.jgit.util.FileUtils;
@@ -431,8 +430,8 @@ public class CheckoutCommandTest extends RepositoryTestCase {
 			config.save();
 
 			// fetch from first repository
-			RefSpec spec = new RefSpec("+refs/heads/*:refs/remotes/origin/*");
-			git2.fetch().setRemote("origin").setRefSpecs(spec).call();
+			git2.fetch().setRemote("origin")
+					.setRefSpecs("+refs/heads/*:refs/remotes/origin/*").call();
 			return db2;
 		}
 	}

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

@@ -56,7 +56,6 @@ import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.transport.FetchResult;
-import org.eclipse.jgit.transport.RefSpec;
 import org.eclipse.jgit.transport.RemoteConfig;
 import org.eclipse.jgit.transport.TagOpt;
 import org.eclipse.jgit.transport.TrackingRefUpdate;
@@ -93,9 +92,8 @@ public class FetchCommandTest extends RepositoryTestCase {
 		RevCommit commit = remoteGit.commit().setMessage("initial commit").call();
 		Ref tagRef = remoteGit.tag().setName("tag").call();
 
-		RefSpec spec = new RefSpec("refs/heads/master:refs/heads/x");
-		git.fetch().setRemote("test").setRefSpecs(spec)
-				.call();
+		git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/x").call();
 
 		assertEquals(commit.getId(),
 				db.resolve(commit.getId().getName() + "^{commit}"));
@@ -108,8 +106,8 @@ public class FetchCommandTest extends RepositoryTestCase {
 		remoteGit.commit().setMessage("commit").call();
 		Ref tagRef = remoteGit.tag().setName("foo").call();
 
-		RefSpec spec = new RefSpec("refs/heads/*:refs/remotes/origin/*");
-		git.fetch().setRemote("test").setRefSpecs(spec)
+		git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/*:refs/remotes/origin/*")
 				.setTagOpt(TagOpt.AUTO_FOLLOW).call();
 
 		assertEquals(tagRef.getObjectId(), db.resolve("foo"));
@@ -120,8 +118,8 @@ public class FetchCommandTest extends RepositoryTestCase {
 		remoteGit.commit().setMessage("commit").call();
 		Ref tagRef = remoteGit.tag().setName("foo").call();
 		remoteGit.commit().setMessage("commit2").call();
-		RefSpec spec = new RefSpec("refs/heads/*:refs/remotes/origin/*");
-		git.fetch().setRemote("test").setRefSpecs(spec)
+		git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/*:refs/remotes/origin/*")
 				.setTagOpt(TagOpt.AUTO_FOLLOW).call();
 		assertEquals(tagRef.getObjectId(), db.resolve("foo"));
 	}
@@ -132,9 +130,8 @@ public class FetchCommandTest extends RepositoryTestCase {
 		remoteGit.checkout().setName("other").setCreateBranch(true).call();
 		remoteGit.commit().setMessage("commit2").call();
 		remoteGit.tag().setName("foo").call();
-		RefSpec spec = new RefSpec(
-				"refs/heads/master:refs/remotes/origin/master");
-		git.fetch().setRemote("test").setRefSpecs(spec)
+		git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/remotes/origin/master")
 				.setTagOpt(TagOpt.AUTO_FOLLOW).call();
 		assertNull(db.resolve("foo"));
 	}
@@ -146,7 +143,7 @@ public class FetchCommandTest extends RepositoryTestCase {
 		Ref tagRef = remoteGit.tag().setName(tagName).call();
 		ObjectId originalId = tagRef.getObjectId();
 
-		RefSpec spec = new RefSpec("refs/heads/*:refs/remotes/origin/*");
+		String spec = "refs/heads/*:refs/remotes/origin/*";
 		git.fetch().setRemote("test").setRefSpecs(spec)
 				.setTagOpt(TagOpt.AUTO_FOLLOW).call();
 		assertEquals(originalId, db.resolve(tagName));
@@ -172,7 +169,7 @@ public class FetchCommandTest extends RepositoryTestCase {
 		remoteGit.commit().setMessage("commit").call();
 		Ref tagRef1 = remoteGit.tag().setName(tagName).call();
 
-		RefSpec spec = new RefSpec("refs/heads/*:refs/remotes/origin/*");
+		String spec = "refs/heads/*:refs/remotes/origin/*";
 		git.fetch().setRemote("test").setRefSpecs(spec)
 				.setTagOpt(TagOpt.AUTO_FOLLOW).call();
 		assertEquals(tagRef1.getObjectId(), db.resolve(tagName));

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

@@ -42,10 +42,13 @@
  */
 package org.eclipse.jgit.api;
 
+import static java.util.stream.Collectors.toList;
+
 import java.io.IOException;
 import java.net.URISyntaxException;
 import java.text.MessageFormat;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 import org.eclipse.jgit.annotations.Nullable;
@@ -387,6 +390,18 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 		return refSpecs;
 	}
 
+	/**
+	 * The ref specs to be used in the fetch operation
+	 *
+	 * @param specs
+	 * @return {@code this}
+	 * @since 4.9
+	 */
+	public FetchCommand setRefSpecs(String... specs) {
+		return setRefSpecs(
+				Arrays.stream(specs).map(RefSpec::new).collect(toList()));
+	}
+
 	/**
 	 * The ref specs to be used in the fetch operation
 	 *
@@ -394,11 +409,7 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 	 * @return {@code this}
 	 */
 	public FetchCommand setRefSpecs(RefSpec... specs) {
-		checkCallable();
-		this.refSpecs.clear();
-		for (RefSpec spec : specs)
-			refSpecs.add(spec);
-		return this;
+		return setRefSpecs(Arrays.asList(specs));
 	}
 
 	/**