Make ArchiveFormats final and implement equals()

This should make it easier to modify ArchiveCommand to allow an
archive format to be registered twice while still noticing if
different callers try to register different implementations for
the same format.

Change-Id: I32261bc8dc1877a853b49e0da0a6e78921791812
Signed-off-by: Jonathan Nieder <jrn@google.com>

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java

@@ -61,7 +61,7 @@
 /**
  * Unix TAR format (ustar + some PAX extensions).
  */
-public class TarFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
+public final class TarFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar")); //$NON-NLS-1$
 
@@ -118,4 +118,14 @@ public void putEntry(ArchiveOutputStream out,
 	public Iterable<String> suffixes() {
 		return SUFFIXES;
 	}
+
+	@Override
+	public boolean equals(Object other) {
+		return (other instanceof TarFormat);
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
 }

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/Tbz2Format.java

@@ -57,7 +57,7 @@
 /**
  * bzip2-compressed tarball (tar.bz2) format.
  */
-public class Tbz2Format implements ArchiveCommand.Format<ArchiveOutputStream> {
+public final class Tbz2Format implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.bz2", ".tbz", ".tbz2")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 
@@ -78,4 +78,14 @@ public void putEntry(ArchiveOutputStream out,
 	public Iterable<String> suffixes() {
 		return SUFFIXES;
 	}
+
+	@Override
+	public boolean equals(Object other) {
+		return (other instanceof Tbz2Format);
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
 }

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java

@@ -57,7 +57,7 @@
 /**
  * gzip-compressed tarball (tar.gz) format.
  */
-public class TgzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
+public final class TgzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.gz", ".tgz")); //$NON-NLS-1$ //$NON-NLS-2$
 
@@ -78,4 +78,14 @@ public void putEntry(ArchiveOutputStream out,
 	public Iterable<String> suffixes() {
 		return SUFFIXES;
 	}
+
+	@Override
+	public boolean equals(Object other) {
+		return (other instanceof TgzFormat);
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
 }

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java

@@ -57,7 +57,7 @@
 /**
  * Xz-compressed tar (tar.xz) format.
  */
-public class TxzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
+public final class TxzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.xz", ".txz")); //$NON-NLS-1$ //$NON-NLS-2$
 
@@ -78,4 +78,14 @@ public void putEntry(ArchiveOutputStream out,
 	public Iterable<String> suffixes() {
 		return SUFFIXES;
 	}
+
+	@Override
+	public boolean equals(Object other) {
+		return (other instanceof TxzFormat);
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
 }

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/ZipFormat.java

@@ -60,7 +60,7 @@
 /**
  * PKWARE's ZIP format.
  */
-public class ZipFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
+public final class ZipFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".zip")); //$NON-NLS-1$
 
@@ -105,4 +105,14 @@ public void putEntry(ArchiveOutputStream out,
 	public Iterable<String> suffixes() {
 		return SUFFIXES;
 	}
+
+	@Override
+	public boolean equals(Object other) {
+		return (other instanceof ZipFormat);
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
 }