From 21e7ea0f9aeec1b792911e1b38b57a949aed79a6 Mon Sep 17 00:00:00 2001
From: Suresh Srinivas <suresh@apache.org>
Date: Wed, 7 Mar 2012 06:57:41 +0000
Subject: [PATCH] HDFS-2477. Merging change r1197801 from trunk to 0.23

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1297866 13f79535-47bb-0310-9956-ffa450edef68
---
 .../server/blockmanagement/TestBlockInfo.java | 123 ++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockInfo.java

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockInfo.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockInfo.java
new file mode 100644
index 00000000000..2750b293560
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockInfo.java
@@ -0,0 +1,123 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.blockmanagement;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Random;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hdfs.protocol.Block;
+import org.apache.hadoop.hdfs.server.common.GenerationStamp;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
+
+/**
+ * This class provides tests for BlockInfo class, which is used in BlocksMap.
+ * The test covers BlockList.listMoveToHead, used for faster block report
+ * processing in DatanodeDescriptor.reportDiff.
+ */
+
+public class TestBlockInfo {
+
+  private static final Log LOG = LogFactory
+      .getLog("org.apache.hadoop.hdfs.TestBlockInfo");
+
+  @Test
+  public void testBlockListMoveToHead() throws Exception {
+    LOG.info("BlockInfo moveToHead tests...");
+
+    final int MAX_BLOCKS = 10;
+
+    DatanodeDescriptor dd = new DatanodeDescriptor();
+    ArrayList<Block> blockList = new ArrayList<Block>(MAX_BLOCKS);
+    ArrayList<BlockInfo> blockInfoList = new ArrayList<BlockInfo>();
+    int headIndex;
+    int curIndex;
+
+    LOG.info("Building block list...");
+    for (int i = 0; i < MAX_BLOCKS; i++) {
+      blockList.add(new Block(i, 0, GenerationStamp.FIRST_VALID_STAMP));
+      blockInfoList.add(new BlockInfo(blockList.get(i), 3));
+      dd.addBlock(blockInfoList.get(i));
+
+      // index of the datanode should be 0
+      assertEquals("Find datanode should be 0", 0, blockInfoList.get(i)
+          .findDatanode(dd));
+    }
+
+    // list length should be equal to the number of blocks we inserted
+    LOG.info("Checking list length...");
+    assertEquals("Length should be MAX_BLOCK", MAX_BLOCKS, dd.numBlocks());
+    Iterator<BlockInfo> it = dd.getBlockIterator();
+    int len = 0;
+    while (it.hasNext()) {
+      it.next();
+      len++;
+    }
+    assertEquals("There should be MAX_BLOCK blockInfo's", MAX_BLOCKS, len);
+
+    headIndex = dd.getHead().findDatanode(dd);
+
+    LOG.info("Moving each block to the head of the list...");
+    for (int i = 0; i < MAX_BLOCKS; i++) {
+      curIndex = blockInfoList.get(i).findDatanode(dd);
+      headIndex = dd.moveBlockToHead(blockInfoList.get(i), curIndex, headIndex);
+      // the moved element must be at the head of the list
+      assertEquals("Block should be at the head of the list now.",
+          blockInfoList.get(i), dd.getHead());
+    }
+
+    // move head of the list to the head - this should not change the list
+    LOG.info("Moving head to the head...");
+
+    BlockInfo temp = dd.getHead();
+    curIndex = 0;
+    headIndex = 0;
+    dd.moveBlockToHead(temp, curIndex, headIndex);
+    assertEquals(
+        "Moving head to the head of the list shopuld not change the list",
+        temp, dd.getHead());
+
+    // check all elements of the list against the original blockInfoList
+    LOG.info("Checking elements of the list...");
+    temp = dd.getHead();
+    assertNotNull("Head should not be null", temp);
+    int c = MAX_BLOCKS - 1;
+    while (temp != null) {
+      assertEquals("Expected element is not on the list",
+          blockInfoList.get(c--), temp);
+      temp = temp.getNext(0);
+    }
+
+    LOG.info("Moving random blocks to the head of the list...");
+    headIndex = dd.getHead().findDatanode(dd);
+    Random rand = new Random();
+    for (int i = 0; i < MAX_BLOCKS; i++) {
+      int j = rand.nextInt(MAX_BLOCKS);
+      curIndex = blockInfoList.get(j).findDatanode(dd);
+      headIndex = dd.moveBlockToHead(blockInfoList.get(j), curIndex, headIndex);
+      // the moved element must be at the head of the list
+      assertEquals("Block should be at the head of the list now.",
+          blockInfoList.get(j), dd.getHead());
+    }
+  }
+}
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