HBASE-22594 Clean up for backup examples (#315)

Signed-off-by: Duo Zhang <zhangduo@apache.org>

hbase-checkstyle/src/main/resources/hbase/checkstyle-suppressions.xml

@@ -40,6 +40,7 @@
   <suppress checks="EmptyBlockCheck" files="org.apache.hadoop.hbase.http.TestServletFilter.java"/>
   <suppress checks="EmptyBlockCheck" files="org.apache.hadoop.hbase.http.TestGlobalFilter.java"/>
   <suppress checks="EmptyBlockCheck" files="org.apache.hadoop.hbase.http.TestPathFilter.java"/>
+  <suppress checks="EmptyBlockCheck" files="org.apache.hadoop.hbase.backup.example.TestZooKeeperTableArchiveClient.java"/>
   <suppress checks="EqualsHashCode" files="org.apache.hadoop.hbase.favored.StartcodeAgnosticServerName.java"/>
   <suppress checks="MethodLength" files="org.apache.hadoop.hbase.tool.coprocessor.Branch1CoprocessorMethods.java"/>
   <suppress checks="IllegalImport" message="org\.apache\.htrace\.core"/>

hbase-server/src/main/java/org/apache/hadoop/hbase/backup/example/HFileArchiveManager.java

@@ -21,12 +21,12 @@ import java.io.IOException;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ZooKeeperConnectionException;
-import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
-import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
+import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
 import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
+import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -68,8 +68,8 @@ class HFileArchiveManager {
 
   /**
    * Stop retaining HFiles for the given table in the archive. HFiles will be cleaned up on the next
-   * pass of the {@link org.apache.hadoop.hbase.master.cleaner.HFileCleaner}, if the HFiles are retained by another
-   * cleaner.
+   * pass of the {@link org.apache.hadoop.hbase.master.cleaner.HFileCleaner}, if the HFiles are
+   * retained by another cleaner.
    * @param table name of the table for which to disable hfile retention.
    * @return <tt>this</tt> for chaining.
    * @throws KeeperException if if we can't reach zookeeper to update the hfile cleaner.
@@ -95,17 +95,16 @@ class HFileArchiveManager {
   }
 
   /**
-   * Perform a best effort enable of hfile retention, which relies on zookeeper communicating the //
-   * * change back to the hfile cleaner.
+   * Perform a best effort enable of hfile retention, which relies on zookeeper communicating the
+   * change back to the hfile cleaner.
    * <p>
    * No attempt is made to make sure that backups are successfully created - it is inherently an
    * <b>asynchronous operation</b>.
    * @param zooKeeper watcher connection to zk cluster
    * @param table table name on which to enable archiving
-   * @throws KeeperException
+   * @throws KeeperException if a ZooKeeper operation fails
    */
-  private void enable(ZKWatcher zooKeeper, byte[] table)
-      throws KeeperException {
+  private void enable(ZKWatcher zooKeeper, byte[] table) throws KeeperException {
     LOG.debug("Ensuring archiving znode exists");
     ZKUtil.createAndFailSilent(zooKeeper, archiveZnode);
 

hbase-server/src/main/java/org/apache/hadoop/hbase/backup/example/LongTermArchivingHFileCleaner.java

@@ -19,7 +19,6 @@ package org.apache.hadoop.hbase.backup.example;
 
 import java.io.IOException;
 
-import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
@@ -27,6 +26,7 @@ import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
 import org.apache.hadoop.hbase.master.cleaner.BaseHFileCleanerDelegate;
 import org.apache.hadoop.hbase.util.FSUtils;
+import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -53,14 +53,18 @@ public class LongTermArchivingHFileCleaner extends BaseHFileCleanerDelegate {
   public boolean isFileDeletable(FileStatus fStat) {
     try {
       // if its a directory, then it can be deleted
-      if (fStat.isDirectory()) return true;
+      if (fStat.isDirectory()) {
+        return true;
+      }
       
       Path file = fStat.getPath();
       // check to see if
       FileStatus[] deleteStatus = FSUtils.listStatus(this.fs, file, null);
       // if the file doesn't exist, then it can be deleted (but should never
       // happen since deleted files shouldn't get passed in)
-      if (deleteStatus == null) return true;
+      if (deleteStatus == null) {
+        return true;
+      }
 
       // otherwise, we need to check the file's table and see its being archived
       Path family = file.getParent();
@@ -69,7 +73,8 @@ public class LongTermArchivingHFileCleaner extends BaseHFileCleanerDelegate {
 
       String tableName = table.getName();
       boolean ret = !archiveTracker.keepHFiles(tableName);
-      LOG.debug("Archiver says to [" + (ret ? "delete" : "keep") + "] files for table:" + tableName);
+      LOG.debug("Archiver says to [" + (ret ? "delete" : "keep") + "] files for table:" +
+          tableName);
       return ret;
     } catch (IOException e) {
       LOG.error("Failed to lookup status of:" + fStat.getPath() + ", keeping it just incase.", e);
@@ -97,13 +102,14 @@ public class LongTermArchivingHFileCleaner extends BaseHFileCleanerDelegate {
 
   @Override
   public void stop(String reason) {
-    if (this.isStopped()) return;
+    if (this.isStopped()) {
+      return;
+    }
+
     super.stop(reason);
     if (this.archiveTracker != null) {
       LOG.info("Stopping " + this.archiveTracker);
       this.archiveTracker.stop();
     }
-
   }
-
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/backup/example/TableHFileArchiveTracker.java

@@ -20,12 +20,12 @@ package org.apache.hadoop.hbase.backup.example;
 import java.io.IOException;
 import java.util.List;
 
-import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
-import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ZooKeeperConnectionException;
-import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZKListener;
+import org.apache.hadoop.hbase.zookeeper.ZKUtil;
+import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
+import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -38,7 +38,7 @@ import org.slf4j.LoggerFactory;
  * archive.
  */
 @InterfaceAudience.Private
-public class TableHFileArchiveTracker extends ZKListener {
+public final class TableHFileArchiveTracker extends ZKListener {
   private static final Logger LOG = LoggerFactory.getLogger(TableHFileArchiveTracker.class);
   public static final String HFILE_ARCHIVE_ZNODE_PARENT = "hfilearchive";
   private HFileArchiveTableMonitor monitor;
@@ -67,7 +67,9 @@ public class TableHFileArchiveTracker extends ZKListener {
   @Override
   public void nodeCreated(String path) {
     // if it is the archive path
-    if (!path.startsWith(archiveHFileZNode)) return;
+    if (!path.startsWith(archiveHFileZNode)) {
+      return;
+    }
 
     LOG.debug("Archive node: " + path + " created");
     // since we are already enabled, just update a single table
@@ -75,7 +77,6 @@ public class TableHFileArchiveTracker extends ZKListener {
 
     // the top level node has come up, so read in all the tables
     if (table.length() == 0) {
-
       checkEnabledAndUpdate();
       return;
     }
@@ -90,7 +91,9 @@ public class TableHFileArchiveTracker extends ZKListener {
 
   @Override
   public void nodeChildrenChanged(String path) {
-    if (!path.startsWith(archiveHFileZNode)) return;
+    if (!path.startsWith(archiveHFileZNode)) {
+      return;
+    }
 
     LOG.debug("Archive node: " + path + " children changed.");
     // a table was added to the archive
@@ -134,7 +137,9 @@ public class TableHFileArchiveTracker extends ZKListener {
 
   @Override
   public void nodeDeleted(String path) {
-    if (!path.startsWith(archiveHFileZNode)) return;
+    if (!path.startsWith(archiveHFileZNode)) {
+      return;
+    }
 
     LOG.debug("Archive node: " + path + " deleted");
     String table = path.substring(archiveHFileZNode.length());
@@ -260,7 +265,10 @@ public class TableHFileArchiveTracker extends ZKListener {
    * Stop this tracker and the passed zookeeper
    */
   public void stop() {
-    if (this.stopped) return;
+    if (this.stopped) {
+      return;
+    }
+
     this.stopped = true;
     this.watcher.close();
   }

hbase-server/src/main/java/org/apache/hadoop/hbase/backup/example/ZKTableArchiveClient.java

@@ -18,14 +18,13 @@
 package org.apache.hadoop.hbase.backup.example;
 
 import java.io.IOException;
-
-import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
-import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
 import org.apache.hadoop.hbase.client.ClusterConnection;
 import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
 import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
+import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.zookeeper.KeeperException;
 
 /**
@@ -110,7 +109,7 @@ public class ZKTableArchiveClient extends Configured {
    * @param table name of the table to check
    * @return <tt>true</tt> if it is, <tt>false</tt> otherwise
    * @throws IOException if a connection to ZooKeeper cannot be established
-   * @throws KeeperException
+   * @throws KeeperException if a ZooKeeper operation fails
    */
   public boolean getArchivingEnabled(byte[] table) throws IOException, KeeperException {
     HFileArchiveManager manager = createHFileArchiveManager();

hbase-server/src/test/java/org/apache/hadoop/hbase/backup/example/TestZooKeeperTableArchiveClient.java

@@ -269,8 +269,11 @@ public class TestZooKeeperTableArchiveClient {
     for (Path file : files) {
       String tableName = file.getParent().getParent().getParent().getName();
       // check to which table this file belongs
-      if (tableName.equals(otherTable)) initialCountForOtherTable++;
-      else if (tableName.equals(STRING_TABLE_NAME)) initialCountForPrimary++;
+      if (tableName.equals(otherTable)) {
+        initialCountForOtherTable++;
+      } else if (tableName.equals(STRING_TABLE_NAME)) {
+        initialCountForPrimary++;
+      }
     }
 
     assertTrue("Didn't archive files for:" + STRING_TABLE_NAME, initialCountForPrimary > 0);
@@ -293,11 +296,13 @@ public class TestZooKeeperTableArchiveClient {
       String tableName = file.getParent().getParent().getParent().getName();
       // ensure we don't have files from the non-archived table
       assertFalse("Have a file from the non-archived table: " + file, tableName.equals(otherTable));
-      if (tableName.equals(STRING_TABLE_NAME)) archivedForPrimary++;
+      if (tableName.equals(STRING_TABLE_NAME)) {
+        archivedForPrimary++;
+      }
     }
 
-    assertEquals("Not all archived files for the primary table were retained.", initialCountForPrimary,
-      archivedForPrimary);
+    assertEquals("Not all archived files for the primary table were retained.",
+        initialCountForPrimary, archivedForPrimary);
 
     // but we still have the archive directory
     assertTrue("Archive directory was deleted via archiver", fs.exists(archiveDir));
@@ -374,7 +379,10 @@ public class TestZooKeeperTableArchiveClient {
 
         @SuppressWarnings("unchecked")
         Iterable<FileStatus> ret = (Iterable<FileStatus>) invocation.callRealMethod();
-        if (counter[0] >= expected) finished.countDown();
+        if (counter[0] >= expected) {
+          finished.countDown();
+        }
+
         return ret;
       }
     }).when(delegateSpy).getDeletableFiles(Mockito.anyListOf(FileStatus.class));
@@ -399,7 +407,11 @@ public class TestZooKeeperTableArchiveClient {
     for (FileStatus file : files) {
       if (file.isDirectory()) {
         List<Path> subFiles = getAllFiles(fs, file.getPath());
-        if (subFiles != null) allFiles.addAll(subFiles);
+
+        if (subFiles != null) {
+          allFiles.addAll(subFiles);
+        }
+
         continue;
       }
       allFiles.add(file.getPath());
@@ -426,7 +438,7 @@ public class TestZooKeeperTableArchiveClient {
    * Create a new hfile in the passed region
    * @param region region to operate on
    * @param columnFamily family for which to add data
-   * @throws IOException
+   * @throws IOException if doing the put or flush fails
    */
   private void createHFileInRegion(HRegion region, byte[] columnFamily) throws IOException {
     // put one row in the region
@@ -438,7 +450,7 @@ public class TestZooKeeperTableArchiveClient {
   }
 
   /**
-   * @param cleaner
+   * @param cleaner the cleaner to use
    */
   private void runCleaner(HFileCleaner cleaner, CountDownLatch finished, Stoppable stop)
       throws InterruptedException {