From c9a360e36059aa46d7090e879762d44d54fa2782 Mon Sep 17 00:00:00 2001
From: Andrew Kyle Purtell <apurtell@apache.org>
Date: Fri, 14 Dec 2012 23:23:05 +0000
Subject: [PATCH] HBASE-7197. Add multi get to RemoteHTable (Elliott Clark)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1422143 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hbase/rest/client/RemoteHTable.java       | 101 +++++++++++++-----
 .../hbase/rest/client/TestRemoteTable.java    |  39 +++++++
 2 files changed, 116 insertions(+), 24 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/rest/client/RemoteHTable.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/rest/client/RemoteHTable.java
index beebe960b05..92fe09202f6 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/rest/client/RemoteHTable.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/rest/client/RemoteHTable.java
@@ -148,6 +148,29 @@ public class RemoteHTable implements HTableInterface {
     return sb.toString();
   }
 
+  protected String buildMultiRowSpec(final byte[][] rows, int maxVersions) {
+    StringBuilder sb = new StringBuilder();
+    sb.append('/');
+    sb.append(Bytes.toStringBinary(name));
+    sb.append("/multiget/");
+    if (rows == null || rows.length == 0) {
+      return sb.toString();
+    }
+    sb.append("?");
+    for(int i=0; i<rows.length; i++) {
+      byte[] rk = rows[i];
+      if (i != 0) {
+        sb.append('&');
+      }
+      sb.append("row=");
+      sb.append(Bytes.toStringBinary(rk));
+    }
+    sb.append("&v=");
+    sb.append(maxVersions);
+
+    return sb.toString();
+  }
+
   protected Result[] buildResultFromModel(final CellSetModel model) {
     List<Result> results = new ArrayList<Result>();
     for (RowModel row: model.getRows()) {
@@ -273,31 +296,66 @@ public class RemoteHTable implements HTableInterface {
     if (get.getFilter() != null) {
       LOG.warn("filters not supported on gets");
     }
+    Result[] results = getResults(spec);
+    if (results.length > 0) {
+      if (results.length > 1) {
+        LOG.warn("too many results for get (" + results.length + ")");
+      }
+      return results[0];
+    } else {
+      return new Result();
+    }
+  }
+
+  public Result[] get(List<Get> gets) throws IOException {
+    byte[][] rows = new byte[gets.size()][];
+    int maxVersions = 1;
+    int count = 0;
+
+    for(Get g:gets) {
+
+      if ( count == 0 ) {
+        maxVersions = g.getMaxVersions();
+      } else if (g.getMaxVersions() != maxVersions) {
+        LOG.warn("MaxVersions on Gets do not match, using the first in the list ("+maxVersions+")");
+      }
+
+      if (g.getFilter() != null) {
+        LOG.warn("filters not supported on gets");
+      }
+
+      rows[count] = g.getRow();
+      count ++;
+    }
+
+    String spec = buildMultiRowSpec(rows, maxVersions);
+
+    return getResults(spec);
+  }
+
+  private Result[] getResults(String spec) throws IOException {
     for (int i = 0; i < maxRetries; i++) {
       Response response = client.get(spec, Constants.MIMETYPE_PROTOBUF);
       int code = response.getCode();
       switch (code) {
-      case 200:
-        CellSetModel model = new CellSetModel();
-        model.getObjectFromMessage(response.getBody());
-        Result[] results = buildResultFromModel(model);
-        if (results.length > 0) {
-          if (results.length > 1) {
-            LOG.warn("too many results for get (" + results.length + ")");
+        case 200:
+          CellSetModel model = new CellSetModel();
+          model.getObjectFromMessage(response.getBody());
+          Result[] results = buildResultFromModel(model);
+          if ( results.length > 0) {
+            return results;
           }
-          return results[0];
-        }
-        // fall through
-      case 404:
-        return new Result();
+          // fall through
+        case 404:
+          return new Result[0];
 
-      case 509:
-        try {
-          Thread.sleep(sleepTime);
-        } catch (InterruptedException e) { }
-        break;
-      default:
-        throw new IOException("get request returned " + code);
+        case 509:
+          try {
+            Thread.sleep(sleepTime);
+          } catch (InterruptedException e) { }
+          break;
+        default:
+          throw new IOException("get request returned " + code);
       }
     }
     throw new IOException("get request timed out");
@@ -708,11 +766,6 @@ public class RemoteHTable implements HTableInterface {
     throw new IOException("batchCallback not supported");
   }
 
-  @Override
-  public Result[] get(List<Get> gets) throws IOException {
-    throw new IOException("get(List<Get>) not supported");
-  }
-
   @Override
   public <T extends CoprocessorProtocol> T coprocessorProxy(Class<T> protocol,
       byte[] row) {
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/rest/client/TestRemoteTable.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/rest/client/TestRemoteTable.java
index 01e23d99a0e..b52a167fbbc 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/rest/client/TestRemoteTable.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/rest/client/TestRemoteTable.java
@@ -216,6 +216,45 @@ public class TestRemoteTable {
     assertEquals(2, count);
   }
 
+  @Test
+  public void testMultiGet() throws Exception {
+    ArrayList<Get> gets = new ArrayList<Get>();
+    gets.add(new Get(ROW_1));
+    gets.add(new Get(ROW_2));
+    Result[] results = remoteTable.get(gets);
+    assertNotNull(results);
+    assertEquals(2, results.length);
+    assertEquals(1, results[0].size());
+    assertEquals(2, results[1].size());
+
+    //Test Versions
+    gets = new ArrayList<Get>();
+    Get g = new Get(ROW_1);
+    g.setMaxVersions(3);
+    gets.add(g);
+    gets.add(new Get(ROW_2));
+    results = remoteTable.get(gets);
+    assertNotNull(results);
+    assertEquals(2, results.length);
+    assertEquals(1, results[0].size());
+    assertEquals(3, results[1].size());
+
+    //404
+    gets = new ArrayList<Get>();
+    gets.add(new Get(Bytes.toBytes("RESALLYREALLYNOTTHERE")));
+    results = remoteTable.get(gets);
+    assertNotNull(results);
+    assertEquals(0, results.length);
+
+    gets = new ArrayList<Get>();
+    gets.add(new Get(Bytes.toBytes("RESALLYREALLYNOTTHERE")));
+    gets.add(new Get(ROW_1));
+    gets.add(new Get(ROW_2));
+    results = remoteTable.get(gets);
+    assertNotNull(results);
+    assertEquals(0, results.length);
+  }
+
   @Test
   public void testPut() throws IOException {
     Put put = new Put(ROW_3);