HBASE-10934 Provide Admin interface to abstract HBaseAdmin (Contributed by Carter)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1588528 13f79535-47bb-0310-9956-ffa450edef68

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionAdapter.java

@@ -110,6 +110,11 @@ class ConnectionAdapter implements ClusterConnection {
     return wrappedConnection.getTable(tableName, pool);
   }
 
+  @Override
+  public Admin getAdmin() throws IOException {
+    return wrappedConnection.getAdmin();
+  }
+
   @Override
   public boolean isMasterRunning() throws MasterNotRunningException,
       ZooKeeperConnectionException {

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionManager.java

@@ -630,6 +630,14 @@ class ConnectionManager {
       return new HTable(tableName, this, pool);
     }
 
+    @Override
+    public Admin getAdmin() throws IOException {
+      if (managed) {
+        throw new IOException("The connection has to be unmanaged.");
+      }
+      return new HBaseAdmin(this);
+    }
+
     private ExecutorService getBatchPool() {
       if (batchPool == null) {
         // shared HTable thread executor not yet initialized

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java

@@ -158,7 +158,7 @@ import com.google.protobuf.ServiceException;
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
-public class HBaseAdmin implements Abortable, Closeable {
+public class HBaseAdmin implements Admin {
   private static final Log LOG = LogFactory.getLog(HBaseAdmin.class);
 
   // We use the implementation class rather then the interface because we

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HConnection.java

@@ -153,6 +153,17 @@ public interface HConnection extends Abortable, Closeable {
    */
   public HTableInterface getTable(TableName tableName, ExecutorService pool)  throws IOException;
 
+  /**
+   * Retrieve an Admin implementation to administer an HBase cluster.
+   * The returned Admin is not guaranteed to be thread-safe.  A new instance should be created for
+   * each using thread.  This is a lightweight operation.  Pooling or caching of the returned
+   * Admin is not recommended.  Note that HConnection needs to be unmanaged
+   * (created with {@link HConnectionManager#createConnection(Configuration)}).
+   *
+   * @return an Admin instance for cluster administration
+   */
+  Admin getAdmin() throws IOException;
+
   /** @return - true if the master server is running
    * @deprecated internal method, do not use thru HConnection */
   @Deprecated

hbase-server/src/main/java/org/apache/hadoop/hbase/client/CoprocessorHConnection.java

@@ -132,6 +132,8 @@ public class CoprocessorHConnection implements ClusterConnection {
     return delegate.getTable(tableName, pool);
   }
 
+  public Admin getAdmin() throws IOException { return delegate.getAdmin(); }
+
   public boolean isMasterRunning() throws MasterNotRunningException, ZooKeeperConnectionException {
     return delegate.isMasterRunning();
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestHCM.java

@@ -85,7 +85,7 @@ import org.junit.experimental.categories.Category;
 import com.google.common.collect.Lists;
 
 /**
- * This class is for testing HCM features
+ * This class is for testing HBaseConnectionManager features
  */
 @Category(MediumTests.class)
 public class TestHCM {
@@ -199,6 +199,19 @@ public class TestHCM {
     otherPool.shutdownNow();
   }
 
+  /**
+   * Naive test to check that HConnection#getAdmin returns a properly constructed HBaseAdmin object
+   * @throws IOException Unable to construct admin
+   */
+  @Test
+  public void testAdminFactory() throws IOException {
+    HConnection con1 = HConnectionManager.createConnection(TEST_UTIL.getConfiguration());
+    HBaseAdmin admin = (HBaseAdmin)con1.getAdmin();
+    assertTrue(admin.getConnection() == con1);
+    assertTrue(admin.getConfiguration() == TEST_UTIL.getConfiguration());
+    con1.close();
+  }
+
   @Ignore ("Fails in IDEs: HBASE-9042") @Test(expected = RegionServerStoppedException.class)
   public void testClusterStatus() throws Exception {
     TableName tn =