Create NoWorkTreeException for bare repositories

Using a custom exception type makes it easire for an application
developer to understand why an exception was thrown out of a method
we declare.  To remain compatiable with existing callers, we still
extend off IllegalStateException.

Change-Id: Ideeef2399b11ca460a2dbb3cd80eb76aa0a025ba
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/RepositorySetupWorkDirTest.java

@@ -48,6 +48,7 @@ import java.io.File;
 import java.io.IOException;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
@@ -136,8 +137,8 @@ public class RepositorySetupWorkDirTest extends LocalDiskRepositoryTestCase {
 		File gitDir = getFile("workdir");
 		try {
 			new FileRepository(gitDir).getWorkTree();
-			fail("Expected IllegalStateException missing");
-		} catch (IllegalStateException e) {
+			fail("Expected NoWorkTreeException missing");
+		} catch (NoWorkTreeException e) {
 			// expected
 		}
 	}
@@ -146,8 +147,8 @@ public class RepositorySetupWorkDirTest extends LocalDiskRepositoryTestCase {
 		File gitDir = getFile("workdir");
 		try {
 			new FileRepository(gitDir).getIndex();
-			fail("Expected IllegalStateException missing");
-		} catch (IllegalStateException e) {
+			fail("Expected NoWorkTreeException missing");
+		} catch (NoWorkTreeException e) {
 			// expected
 		}
 	}
@@ -156,8 +157,8 @@ public class RepositorySetupWorkDirTest extends LocalDiskRepositoryTestCase {
 		File gitDir = getFile("workdir");
 		try {
 			new FileRepository(gitDir).getIndexFile();
-			fail("Expected Exception missing");
-		} catch (IllegalStateException e) {
+			fail("Expected NoWorkTreeException missing");
+		} catch (NoWorkTreeException e) {
 			// expected
 		}
 	}

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCache.java

@@ -62,6 +62,7 @@ import java.util.Comparator;
 
 import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.errors.CorruptObjectException;
+import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.errors.UnmergedPathException;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
@@ -168,7 +169,7 @@ public class DirCache {
 	 *            repository the caller wants to read the default index of.
 	 * @return a cache representing the contents of the specified index file (if
 	 *         it exists) or an empty cache if the file does not exist.
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if the repository is bare (lacks a working directory).
 	 * @throws IOException
 	 *             the index file is present but could not be read.
@@ -177,7 +178,7 @@ public class DirCache {
 	 *             library does not support.
 	 */
 	public static DirCache read(final Repository db)
-			throws CorruptObjectException, IOException {
+			throws NoWorkTreeException, CorruptObjectException, IOException {
 		return read(db.getIndexFile());
 	}
 
@@ -233,7 +234,7 @@ public class DirCache {
 	 *            repository the caller wants to read the default index of.
 	 * @return a cache representing the contents of the specified index file (if
 	 *         it exists) or an empty cache if the file does not exist.
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if the repository is bare (lacks a working directory).
 	 * @throws IOException
 	 *             the index file is present but could not be read, or the lock
@@ -243,7 +244,7 @@ public class DirCache {
 	 *             library does not support.
 	 */
 	public static DirCache lock(final Repository db)
-			throws CorruptObjectException, IOException {
+			throws NoWorkTreeException, CorruptObjectException, IOException {
 		return lock(db.getIndexFile());
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/errors/NoWorkTreeException.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.errors;
+
+import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.lib.Repository;
+
+/**
+ * Indicates a {@link Repository} has no working directory, and is thus bare.
+ */
+public class NoWorkTreeException extends IllegalStateException {
+	private static final long serialVersionUID = 1L;
+
+	/** Creates an exception indicating there is no work tree for a repository. */
+	public NoWorkTreeException() {
+		super(JGitText.get().bareRepositoryNoWorkdirAndIndex);
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

@@ -62,6 +62,7 @@ import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.errors.RevisionSyntaxException;
 import org.eclipse.jgit.events.ListenerList;
 import org.eclipse.jgit.events.RepositoryEvent;
@@ -860,13 +861,12 @@ public abstract class Repository {
 	 *         {@link Repository}
 	 * @throws IOException
 	 *             if the index can not be read
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if this is bare (see {@link #isBare()})
 	 */
-	public GitIndex getIndex() throws IOException, IllegalStateException {
+	public GitIndex getIndex() throws IOException, NoWorkTreeException {
 		if (isBare())
-			throw new IllegalStateException(
-					JGitText.get().bareRepositoryNoWorkdirAndIndex);
+			throw new NoWorkTreeException();
 		if (index == null) {
 			index = new GitIndex(this);
 			index.read();
@@ -878,13 +878,12 @@ public abstract class Repository {
 
 	/**
 	 * @return the index file location
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if this is bare (see {@link #isBare()})
 	 */
-	public File getIndexFile() throws IllegalStateException {
+	public File getIndexFile() throws NoWorkTreeException {
 		if (isBare())
-			throw new IllegalStateException(
-					JGitText.get().bareRepositoryNoWorkdirAndIndex);
+			throw new NoWorkTreeException();
 		return indexFile;
 	}
 
@@ -1036,13 +1035,12 @@ public abstract class Repository {
 	/**
 	 * @return the root directory of the working tree, where files are checked
 	 *         out for viewing and editing.
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if the repository is bare and has no working directory.
 	 */
-	public File getWorkTree() throws IllegalStateException {
+	public File getWorkTree() throws NoWorkTreeException {
 		if (isBare())
-			throw new IllegalStateException(
-					JGitText.get().bareRepositoryNoWorkdirAndIndex);
+			throw new NoWorkTreeException();
 		return workTree;
 	}
 
@@ -1085,13 +1083,12 @@ public abstract class Repository {
 	 * @return a String containing the content of the MERGE_MSG file or
 	 *         {@code null} if this file doesn't exist
 	 * @throws IOException
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if the repository is "bare"
 	 */
-	public String readMergeCommitMsg() throws IOException {
+	public String readMergeCommitMsg() throws IOException, NoWorkTreeException {
 		if (isBare() || getDirectory() == null)
-			throw new IllegalStateException(
-					JGitText.get().bareRepositoryNoWorkdirAndIndex);
+			throw new NoWorkTreeException();
 
 		File mergeMsgFile = new File(getDirectory(), Constants.MERGE_MSG);
 		try {
@@ -1112,13 +1109,12 @@ public abstract class Repository {
 	 *         file or {@code null} if this file doesn't exist. Also if the file
 	 *         exists but is empty {@code null} will be returned
 	 * @throws IOException
-	 * @throws IllegalStateException
+	 * @throws NoWorkTreeException
 	 *             if the repository is "bare"
 	 */
-	public List<ObjectId> readMergeHeads() throws IOException {
+	public List<ObjectId> readMergeHeads() throws IOException, NoWorkTreeException {
 		if (isBare() || getDirectory() == null)
-			throw new IllegalStateException(
-					JGitText.get().bareRepositoryNoWorkdirAndIndex);
+			throw new NoWorkTreeException();
 
 		File mergeHeadFile = new File(getDirectory(), Constants.MERGE_HEAD);
 		byte[] raw;