/**
    *
    * 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.hbase.regionserver;
  
  import static org.apache.hadoop.hbase.regionserver.StripeStoreFileManager.OPEN_KEY;
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.KeyValue.KVComparator;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.mockito.Mockito;
  
  
  @Category(SmallTests.class)
  public class TestStripeStoreFileManager {
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private static final Path BASEDIR =
        TEST_UTIL.getDataTestDir(TestStripeStoreFileManager.class.getSimpleName());
    private static final Path CFDIR = HStore.getStoreHomedir(BASEDIR, "region", Bytes.toBytes("cf"));
  
    private static final byte[] KEY_A = Bytes.toBytes("aaa");
    private static final byte[] KEY_B = Bytes.toBytes("bbb");
    private static final byte[] KEY_C = Bytes.toBytes("ccc");
    private static final byte[] KEY_D = Bytes.toBytes("ddd");
  
    private static final KeyValue KV_A = new KeyValue(KEY_A, 0L);
    private static final KeyValue KV_B = new KeyValue(KEY_B, 0L);
    private static final KeyValue KV_C = new KeyValue(KEY_C, 0L);
    private static final KeyValue KV_D = new KeyValue(KEY_D, 0L);
  
    @Before
    public void setUp() throws Exception {
      FileSystem fs = TEST_UTIL.getTestFileSystem();
      if (!fs.mkdirs(CFDIR)) {
        throw new IOException("Cannot create test directory " + CFDIR);
      }
    }
  
    @After
    public void tearDown() throws Exception {
      FileSystem fs = TEST_UTIL.getTestFileSystem();
      if (fs.exists(CFDIR) && !fs.delete(CFDIR, true)) {
        throw new IOException("Cannot delete test directory " + CFDIR);
      }
    }
  
    @Test
    public void testInsertFilesIntoL0() throws Exception {
      StripeStoreFileManager manager = createManager();
      MockStoreFile sf = createFile();
      manager.insertNewFiles(al(sf));
      assertEquals(1, manager.getStorefileCount());
      Collection<StoreFile> filesForGet = manager.getFilesForScanOrGet(KEY_A, true, KEY_A, true);
      assertEquals(1, filesForGet.size());
      assertTrue(filesForGet.contains(sf));
  
      // Add some stripes and make sure we get this file for every stripe.
      manager.addCompactionResults(al(), al(createFile(OPEN_KEY, KEY_B),
          createFile(KEY_B, OPEN_KEY)));
     assertTrue(manager.getFilesForScanOrGet(KEY_A, true, KEY_A, true).contains(sf));
     assertTrue(manager.getFilesForScanOrGet(KEY_C, true, KEY_C, true).contains(sf));
   }
 
   @Test
   public void testClearFiles() throws Exception {
     StripeStoreFileManager manager = createManager();
     manager.insertNewFiles(al(createFile()));
     manager.insertNewFiles(al(createFile()));
     manager.addCompactionResults(al(), al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_B, OPEN_KEY)));
     assertEquals(4, manager.getStorefileCount());
     Collection<StoreFile> allFiles = manager.clearFiles();
     assertEquals(4, allFiles.size());
     assertEquals(0, manager.getStorefileCount());
     assertEquals(0, manager.getStorefiles().size());
   }
 
   private static ArrayList<StoreFile> dumpIterator(Iterator<StoreFile> iter) {
     ArrayList<StoreFile> result = new ArrayList<StoreFile>();
     for (; iter.hasNext(); result.add(iter.next()));
     return result;
   }
 
   @Test
   public void testRowKeyBefore() throws Exception {
     StripeStoreFileManager manager = createManager();
     StoreFile l0File = createFile(), l0File2 = createFile();
     manager.insertNewFiles(al(l0File));
     manager.insertNewFiles(al(l0File2));
     // Get candidate files.
     Iterator<StoreFile> sfs = manager.getCandidateFilesForRowKeyBefore(KV_B);
     sfs.next();
     sfs.remove();
     // Suppose we found a candidate in this file... make sure L0 file remaining is not removed.
     sfs = manager.updateCandidateFilesForRowKeyBefore(sfs, KV_B, KV_A);
     assertTrue(sfs.hasNext());
     // Now add some stripes (remove L0 file too)
     MockStoreFile stripe0a = createFile(0, 100, OPEN_KEY, KEY_B),
         stripe1 = createFile(KEY_B, OPEN_KEY);
     manager.addCompactionResults(al(l0File), al(stripe0a, stripe1));
     manager.removeCompactedFiles(al(l0File));
     // If we want a key <= KEY_A, we should get everything except stripe1.
     ArrayList<StoreFile> sfsDump = dumpIterator(manager.getCandidateFilesForRowKeyBefore(KV_A));
     assertEquals(2, sfsDump.size());
     assertTrue(sfsDump.contains(stripe0a));
     assertFalse(sfsDump.contains(stripe1));
     // If we want a key <= KEY_B, we should get everything since lower bound is inclusive.
     sfsDump = dumpIterator(manager.getCandidateFilesForRowKeyBefore(KV_B));
     assertEquals(3, sfsDump.size());
     assertTrue(sfsDump.contains(stripe1));
     // For KEY_D, we should also get everything.
     sfsDump = dumpIterator(manager.getCandidateFilesForRowKeyBefore(KV_D));
     assertEquals(3, sfsDump.size());
     // Suppose in the first file we found candidate with KEY_C.
     // Then, stripe0 no longer matters and should be removed, but stripe1 should stay.
     sfs = manager.getCandidateFilesForRowKeyBefore(KV_D);
     sfs.next(); // Skip L0 file.
     sfs.remove();
     sfs = manager.updateCandidateFilesForRowKeyBefore(sfs, KV_D, KV_C);
     assertEquals(stripe1, sfs.next());
     assertFalse(sfs.hasNext());
     // Add one more, later, file to stripe0, remove the last annoying L0 file.
     // This file should be returned in preference to older L0 file; also, after we get
     // a candidate from the first file, the old one should not be removed.
     StoreFile stripe0b = createFile(0, 101, OPEN_KEY, KEY_B);
     manager.addCompactionResults(al(l0File2), al(stripe0b));
     manager.removeCompactedFiles(al(l0File2));
     sfs = manager.getCandidateFilesForRowKeyBefore(KV_A);
     assertEquals(stripe0b, sfs.next());
     sfs.remove();
     sfs = manager.updateCandidateFilesForRowKeyBefore(sfs, KV_A, KV_A);
     assertEquals(stripe0a, sfs.next());
   }
 
   @Test
   public void testGetSplitPointEdgeCases() throws Exception {
     StripeStoreFileManager manager = createManager();
     // No files => no split.
     assertNull(manager.getSplitPoint());
 
     // If there are no stripes, should pick midpoint from the biggest file in L0.
     MockStoreFile sf5 = createFile(5, 0);
     sf5.splitPoint = new byte[1];
     manager.insertNewFiles(al(sf5));
     manager.insertNewFiles(al(createFile(1, 0)));
     assertArrayEquals(sf5.splitPoint, manager.getSplitPoint());
 
     // Same if there's one stripe but the biggest file is still in L0.
     manager.addCompactionResults(al(), al(createFile(2, 0, OPEN_KEY, OPEN_KEY)));
     assertArrayEquals(sf5.splitPoint, manager.getSplitPoint());
 
     // If the biggest file is in the stripe, should get from it.
     MockStoreFile sf6 = createFile(6, 0, OPEN_KEY, OPEN_KEY);
     sf6.splitPoint = new byte[1];
     manager.addCompactionResults(al(), al(sf6));
     assertArrayEquals(sf6.splitPoint, manager.getSplitPoint());
   }
 
   @Test
   public void testGetStripeBoundarySplits() throws Exception {
     /* First number - split must be after this stripe; further numbers - stripes */
     verifySplitPointScenario(5, false, 0f,     2, 1, 1, 1, 1, 1, 10);
     verifySplitPointScenario(0, false, 0f,     6, 3, 1, 1, 2);
     verifySplitPointScenario(2, false, 0f,     1, 1, 1, 1, 2);
     verifySplitPointScenario(0, false, 0f,     5, 4);
     verifySplitPointScenario(2, false, 0f,     5, 2, 5, 5, 5);
   }
 
   @Test
   public void testGetUnbalancedSplits() throws Exception {
     /* First number - split must be inside/after this stripe; further numbers - stripes */
     verifySplitPointScenario(0, false, 2.1f,      4, 4, 4); // 8/4 is less than 2.1f
     verifySplitPointScenario(1, true,  1.5f,      4, 4, 4); // 8/4 > 6/6
     verifySplitPointScenario(1, false, 1.1f,      3, 4, 1, 1, 2, 2); // 7/6 < 8/5
     verifySplitPointScenario(1, false, 1.1f,      3, 6, 1, 1, 2, 2); // 9/6 == 9/6
     verifySplitPointScenario(1, true,  1.1f,      3, 8, 1, 1, 2, 2); // 11/6 > 10/7
     verifySplitPointScenario(3, false, 1.1f,      2, 2, 1, 1, 4, 3); // reverse order
     verifySplitPointScenario(4, true,  1.1f,      2, 2, 1, 1, 8, 3); // reverse order
     verifySplitPointScenario(0, true,  1.5f,      10, 4); // 10/4 > 9/5
     verifySplitPointScenario(0, false, 1.4f,      6, 4);  // 6/4 == 6/4
     verifySplitPointScenario(1, true,  1.5f,      4, 10); // reverse just in case
     verifySplitPointScenario(0, false, 1.4f,      4, 6);  // reverse just in case
   }
 
 
   /**
    * Verifies scenario for finding a split point.
    * @param splitPointAfter Stripe to expect the split point at/after.
    * @param shouldSplitStripe If true, the split point is expected in the middle of the above
    *                          stripe; if false, should be at the end.
    * @param splitRatioToVerify Maximum split imbalance ratio.
    * @param sizes Stripe sizes.
    */
   private void verifySplitPointScenario(int splitPointAfter, boolean shouldSplitStripe,
       float splitRatioToVerify, int... sizes) throws Exception {
     assertTrue(sizes.length > 1);
     ArrayList<StoreFile> sfs = new ArrayList<StoreFile>();
     for (int sizeIx = 0; sizeIx < sizes.length; ++sizeIx) {
       byte[] startKey = (sizeIx == 0) ? OPEN_KEY : Bytes.toBytes(sizeIx - 1);
       byte[] endKey = (sizeIx == sizes.length - 1) ? OPEN_KEY : Bytes.toBytes(sizeIx);
       MockStoreFile sf = createFile(sizes[sizeIx], 0, startKey, endKey);
       sf.splitPoint = Bytes.toBytes(-sizeIx); // set split point to the negative index
       sfs.add(sf);
     }
 
     Configuration conf = HBaseConfiguration.create();
     if (splitRatioToVerify != 0) {
       conf.setFloat(StripeStoreConfig.MAX_REGION_SPLIT_IMBALANCE_KEY, splitRatioToVerify);
     }
     StripeStoreFileManager manager = createManager(al(), conf);
     manager.addCompactionResults(al(), sfs);
     int result = Bytes.toInt(manager.getSplitPoint());
     // Either end key and thus positive index, or "middle" of the file and thus negative index.
     assertEquals(splitPointAfter * (shouldSplitStripe ? -1 : 1), result);
   }
 
   private static byte[] keyAfter(byte[] key) {
     return Arrays.copyOf(key, key.length + 1);
   }
 
   @Test
   public void testGetFilesForGetAndScan() throws Exception {
     StripeStoreFileManager manager = createManager();
     verifyGetAndScanScenario(manager, null, null);
     verifyGetAndScanScenario(manager, KEY_B, KEY_C);
 
     // Populate one L0 file.
     MockStoreFile sf0 = createFile();
     manager.insertNewFiles(al(sf0));
     verifyGetAndScanScenario(manager, null, null,   sf0);
     verifyGetAndScanScenario(manager, null, KEY_C,  sf0);
     verifyGetAndScanScenario(manager, KEY_B, null,  sf0);
     verifyGetAndScanScenario(manager, KEY_B, KEY_C, sf0);
 
     // Populate a bunch of files for stripes, keep L0.
     MockStoreFile sfA = createFile(OPEN_KEY, KEY_A);
     MockStoreFile sfB = createFile(KEY_A, KEY_B);
     MockStoreFile sfC = createFile(KEY_B, KEY_C);
     MockStoreFile sfD = createFile(KEY_C, KEY_D);
     MockStoreFile sfE = createFile(KEY_D, OPEN_KEY);
     manager.addCompactionResults(al(), al(sfA, sfB, sfC, sfD, sfE));
 
     verifyGetAndScanScenario(manager, null, null,              sf0, sfA, sfB, sfC, sfD, sfE);
     verifyGetAndScanScenario(manager, keyAfter(KEY_A), null,   sf0, sfB, sfC, sfD, sfE);
     verifyGetAndScanScenario(manager, null, keyAfter(KEY_C),   sf0, sfA, sfB, sfC, sfD);
     verifyGetAndScanScenario(manager, KEY_B, null,             sf0, sfC, sfD, sfE);
     verifyGetAndScanScenario(manager, null, KEY_C,             sf0, sfA, sfB, sfC, sfD);
     verifyGetAndScanScenario(manager, KEY_B, keyAfter(KEY_B),  sf0, sfC);
     verifyGetAndScanScenario(manager, keyAfter(KEY_A), KEY_B,  sf0, sfB, sfC);
     verifyGetAndScanScenario(manager, KEY_D, KEY_D,            sf0, sfE);
     verifyGetAndScanScenario(manager, keyAfter(KEY_B), keyAfter(KEY_C), sf0, sfC, sfD);
   }
 
   private void verifyGetAndScanScenario(StripeStoreFileManager manager,
       byte[] start, byte[] end, StoreFile... results) throws Exception {
     verifyGetOrScanScenario(manager, true, start, end, results);
     verifyGetOrScanScenario(manager, false, start, end, results);
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testLoadFilesWithRecoverableBadFiles() throws Exception {
     // In L0, there will be file w/o metadata (real L0, 3 files with invalid metadata, and 3
     // files that overlap valid stripes in various ways). Note that the 4th way to overlap the
     // stripes will cause the structure to be mostly scraped, and is tested separately.
     ArrayList<StoreFile> validStripeFiles = al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_B, KEY_C), createFile(KEY_C, OPEN_KEY),
         createFile(KEY_C, OPEN_KEY));
     ArrayList<StoreFile> filesToGoToL0 = al(createFile(), createFile(null, KEY_A),
         createFile(KEY_D, null), createFile(KEY_D, KEY_A), createFile(keyAfter(KEY_A), KEY_C),
         createFile(OPEN_KEY, KEY_D), createFile(KEY_D, keyAfter(KEY_D)));
     ArrayList<StoreFile> allFilesToGo = flattenLists(validStripeFiles, filesToGoToL0);
     Collections.shuffle(allFilesToGo);
     StripeStoreFileManager manager = createManager(allFilesToGo);
     List<StoreFile> l0Files = manager.getLevel0Files();
     assertEquals(filesToGoToL0.size(), l0Files.size());
     for (StoreFile sf : filesToGoToL0) {
       assertTrue(l0Files.contains(sf));
     }
     verifyAllFiles(manager, allFilesToGo);
   }
 
   @Test
   public void testLoadFilesWithBadStripe() throws Exception {
     // Current "algorithm" will see the after-B key before C key, add it as valid stripe,
     // and then fail all other stripes. So everything would end up in L0.
     ArrayList<StoreFile> allFilesToGo = al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_B, KEY_C), createFile(KEY_C, OPEN_KEY),
         createFile(KEY_B, keyAfter(KEY_B)));
     Collections.shuffle(allFilesToGo);
     StripeStoreFileManager manager = createManager(allFilesToGo);
     assertEquals(allFilesToGo.size(), manager.getLevel0Files().size());
   }
 
   @Test
   public void testLoadFilesWithGaps() throws Exception {
     // Stripes must not have gaps. If they do, everything goes to L0.
     StripeStoreFileManager manager =
       createManager(al(createFile(OPEN_KEY, KEY_B), createFile(KEY_C, OPEN_KEY)));
     assertEquals(2, manager.getLevel0Files().size());
     // Just one open stripe should be ok.
     manager = createManager(al(createFile(OPEN_KEY, OPEN_KEY)));
     assertEquals(0, manager.getLevel0Files().size());
     assertEquals(1, manager.getStorefileCount());
   }
 
   @Test
   public void testLoadFilesAfterSplit() throws Exception {
     // If stripes are good but have non-open ends, they must be treated as open ends.
     MockStoreFile sf = createFile(KEY_B, KEY_C);
     StripeStoreFileManager manager = createManager(al(createFile(OPEN_KEY, KEY_B), sf));
     assertEquals(0, manager.getLevel0Files().size());
     // Here, [B, C] is logically [B, inf), so we should be able to compact it to that only.
     verifyInvalidCompactionScenario(manager, al(sf), al(createFile(KEY_B, KEY_C)));
     manager.addCompactionResults(al(sf), al(createFile(KEY_B, OPEN_KEY)));
     manager.removeCompactedFiles(al(sf));
     // Do the same for other variants.
     manager = createManager(al(sf, createFile(KEY_C, OPEN_KEY)));
     verifyInvalidCompactionScenario(manager, al(sf), al(createFile(KEY_B, KEY_C)));
     manager.addCompactionResults(al(sf), al(createFile(OPEN_KEY, KEY_C)));
     manager.removeCompactedFiles(al(sf));
     manager = createManager(al(sf));
     verifyInvalidCompactionScenario(manager, al(sf), al(createFile(KEY_B, KEY_C)));
     manager.addCompactionResults(al(sf), al(createFile(OPEN_KEY, OPEN_KEY)));
   }
 
   @Test
   public void testAddingCompactionResults() throws Exception {
     StripeStoreFileManager manager = createManager();
     // First, add some L0 files and "compact" one with new stripe creation.
     StoreFile sf_L0_0a = createFile(), sf_L0_0b = createFile();
     manager.insertNewFiles(al(sf_L0_0a, sf_L0_0b));
 
     // Try compacting with invalid new branches (gaps, overlaps) - no effect.
     verifyInvalidCompactionScenario(manager, al(sf_L0_0a), al(createFile(OPEN_KEY, KEY_B)));
     verifyInvalidCompactionScenario(manager, al(sf_L0_0a), al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_C, OPEN_KEY)));
     verifyInvalidCompactionScenario(manager, al(sf_L0_0a), al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_B, OPEN_KEY), createFile(KEY_A, KEY_D)));
     verifyInvalidCompactionScenario(manager, al(sf_L0_0a), al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_A, KEY_B), createFile(KEY_B, OPEN_KEY)));
 
     StoreFile sf_i2B_0 = createFile(OPEN_KEY, KEY_B);
     StoreFile sf_B2C_0 = createFile(KEY_B, KEY_C);
     StoreFile sf_C2i_0 = createFile(KEY_C, OPEN_KEY);
     manager.addCompactionResults(al(sf_L0_0a), al(sf_i2B_0, sf_B2C_0, sf_C2i_0));
     manager.removeCompactedFiles(al(sf_L0_0a));
     verifyAllFiles(manager, al(sf_L0_0b, sf_i2B_0, sf_B2C_0, sf_C2i_0));
 
     // Add another l0 file, "compact" both L0 into two stripes
     StoreFile sf_L0_1 = createFile();
     StoreFile sf_i2B_1 = createFile(OPEN_KEY, KEY_B);
     StoreFile sf_B2C_1 = createFile(KEY_B, KEY_C);
     manager.insertNewFiles(al(sf_L0_1));
     manager.addCompactionResults(al(sf_L0_0b, sf_L0_1), al(sf_i2B_1, sf_B2C_1));
     manager.removeCompactedFiles(al(sf_L0_0b, sf_L0_1));
     verifyAllFiles(manager, al(sf_i2B_0, sf_B2C_0, sf_C2i_0, sf_i2B_1, sf_B2C_1));
 
     // Try compacting with invalid file (no metadata) - should add files to L0.
     StoreFile sf_L0_2 = createFile(null, null);
     manager.addCompactionResults(al(), al(sf_L0_2));
     manager.removeCompactedFiles(al());
     verifyAllFiles(manager, al(sf_i2B_0, sf_B2C_0, sf_C2i_0, sf_i2B_1, sf_B2C_1, sf_L0_2));
     // Remove it...
     manager.addCompactionResults(al(sf_L0_2), al());
     manager.removeCompactedFiles(al(sf_L0_2));
 
     // Do regular compaction in the first stripe.
     StoreFile sf_i2B_3 = createFile(OPEN_KEY, KEY_B);
     manager.addCompactionResults(al(sf_i2B_0, sf_i2B_1), al(sf_i2B_3));
     manager.removeCompactedFiles(al(sf_i2B_0, sf_i2B_1));
     verifyAllFiles(manager, al(sf_B2C_0, sf_C2i_0, sf_B2C_1, sf_i2B_3));
 
     // Rebalance two stripes.
     StoreFile sf_B2D_4 = createFile(KEY_B, KEY_D);
     StoreFile sf_D2i_4 = createFile(KEY_D, OPEN_KEY);
     manager.addCompactionResults(al(sf_B2C_0, sf_C2i_0, sf_B2C_1), al(sf_B2D_4, sf_D2i_4));
     manager.removeCompactedFiles(al(sf_B2C_0, sf_C2i_0, sf_B2C_1));
     verifyAllFiles(manager, al(sf_i2B_3, sf_B2D_4, sf_D2i_4));
 
     // Split the first stripe.
     StoreFile sf_i2A_5 = createFile(OPEN_KEY, KEY_A);
     StoreFile sf_A2B_5 = createFile(KEY_A, KEY_B);
     manager.addCompactionResults(al(sf_i2B_3), al(sf_i2A_5, sf_A2B_5));
     manager.removeCompactedFiles(al(sf_i2B_3));
     verifyAllFiles(manager, al(sf_B2D_4, sf_D2i_4, sf_i2A_5, sf_A2B_5));
 
     // Split the middle stripe.
     StoreFile sf_B2C_6 = createFile(KEY_B, KEY_C);
     StoreFile sf_C2D_6 = createFile(KEY_C, KEY_D);
     manager.addCompactionResults(al(sf_B2D_4), al(sf_B2C_6, sf_C2D_6));
     manager.removeCompactedFiles(al(sf_B2D_4));
     verifyAllFiles(manager, al(sf_D2i_4, sf_i2A_5, sf_A2B_5, sf_B2C_6, sf_C2D_6));
 
     // Merge two different middle stripes.
     StoreFile sf_A2C_7 = createFile(KEY_A, KEY_C);
     manager.addCompactionResults(al(sf_A2B_5, sf_B2C_6), al(sf_A2C_7));
     manager.removeCompactedFiles(al(sf_A2B_5, sf_B2C_6));
     verifyAllFiles(manager, al(sf_D2i_4, sf_i2A_5, sf_C2D_6, sf_A2C_7));
 
     // Merge lower half.
     StoreFile sf_i2C_8 = createFile(OPEN_KEY, KEY_C);
     manager.addCompactionResults(al(sf_i2A_5, sf_A2C_7), al(sf_i2C_8));
     manager.removeCompactedFiles(al(sf_i2A_5, sf_A2C_7));
     verifyAllFiles(manager, al(sf_D2i_4, sf_C2D_6, sf_i2C_8));
 
     // Merge all.
     StoreFile sf_i2i_9 = createFile(OPEN_KEY, OPEN_KEY);
     manager.addCompactionResults(al(sf_D2i_4, sf_C2D_6, sf_i2C_8), al(sf_i2i_9));
     manager.removeCompactedFiles(al(sf_D2i_4, sf_C2D_6, sf_i2C_8));
     verifyAllFiles(manager, al(sf_i2i_9));
   }
 
   @Test
   public void testCompactionAndFlushConflict() throws Exception {
     // Add file flush into stripes
     StripeStoreFileManager sfm = createManager();
     assertEquals(0, sfm.getStripeCount());
     StoreFile sf_i2c = createFile(OPEN_KEY, KEY_C), sf_c2i = createFile(KEY_C, OPEN_KEY);
     sfm.insertNewFiles(al(sf_i2c, sf_c2i));
     assertEquals(2, sfm.getStripeCount());
     // Now try to add conflicting flush - should throw.
     StoreFile sf_i2d = createFile(OPEN_KEY, KEY_D), sf_d2i = createFile(KEY_D, OPEN_KEY);
     sfm.insertNewFiles(al(sf_i2d, sf_d2i));
     assertEquals(2, sfm.getStripeCount());
     assertEquals(2, sfm.getLevel0Files().size());
     verifyGetAndScanScenario(sfm, KEY_C, KEY_C, sf_i2d, sf_d2i, sf_c2i);
     // Remove these files.
     sfm.addCompactionResults(al(sf_i2d, sf_d2i), al());
     sfm.removeCompactedFiles(al(sf_i2d, sf_d2i));
     assertEquals(0, sfm.getLevel0Files().size());
     // Add another file to stripe; then "rebalance" stripes w/o it - the file, which was
     // presumably flushed during compaction, should go to L0.
     StoreFile sf_i2c_2 = createFile(OPEN_KEY, KEY_C);
     sfm.insertNewFiles(al(sf_i2c_2));
     sfm.addCompactionResults(al(sf_i2c, sf_c2i), al(sf_i2d, sf_d2i));
     sfm.removeCompactedFiles(al(sf_i2c, sf_c2i));
     assertEquals(1, sfm.getLevel0Files().size());
     verifyGetAndScanScenario(sfm, KEY_C, KEY_C, sf_i2d, sf_i2c_2);
   }
 
   @Test
   public void testEmptyResultsForStripes() throws Exception {
     // Test that we can compact L0 into a subset of stripes.
     StripeStoreFileManager manager = createManager();
     StoreFile sf0a = createFile();
     StoreFile sf0b = createFile();
     manager.insertNewFiles(al(sf0a));
     manager.insertNewFiles(al(sf0b));
     ArrayList<StoreFile> compacted = al(createFile(OPEN_KEY, KEY_B),
         createFile(KEY_B, KEY_C), createFile(KEY_C, OPEN_KEY));
     manager.addCompactionResults(al(sf0a), compacted);
     manager.removeCompactedFiles(al(sf0a));
     // Next L0 compaction only produces file for the first and last stripe.
     ArrayList<StoreFile> compacted2 = al(createFile(OPEN_KEY, KEY_B), createFile(KEY_C, OPEN_KEY));
     manager.addCompactionResults(al(sf0b), compacted2);
     manager.removeCompactedFiles(al(sf0b));
     compacted.addAll(compacted2);
     verifyAllFiles(manager, compacted);
   }
 
   @Test
   public void testPriority() throws Exception {
     // Expected priority, file limit, stripe count, files per stripe, l0 files.
     testPriorityScenario(5,    5, 0, 0, 0);
     testPriorityScenario(2,    5, 0, 0, 3);
     testPriorityScenario(4,   25, 5, 1, 0); // example case.
     testPriorityScenario(3,   25, 5, 1, 1); // L0 files counts for all stripes.
     testPriorityScenario(3,   25, 5, 2, 0); // file to each stripe - same as one L0 file.
     testPriorityScenario(2,   25, 5, 4, 0); // 1 is priority user, so 2 is returned.
     testPriorityScenario(2,   25, 5, 4, 4); // don't return higher than user unless over limit.
     testPriorityScenario(2,   25, 5, 1, 10); // same.
     testPriorityScenario(0,   25, 5, 4, 5); // at limit.
     testPriorityScenario(-5,  25, 5, 6, 0); // over limit!
     testPriorityScenario(-1,  25, 0, 0, 26); // over limit with just L0
   }
 
   private void testPriorityScenario(int expectedPriority,
       int limit, int stripes, int filesInStripe, int l0Files) throws Exception
   {
     final byte[][] keys = { KEY_A, KEY_B, KEY_C, KEY_D };
     assertTrue(stripes <= keys.length + 1);
     Configuration conf = TEST_UTIL.getConfiguration();
     conf.setInt("hbase.hstore.blockingStoreFiles", limit);
     StripeStoreFileManager sfm = createManager(al(), conf);
     for (int i = 0; i < l0Files; ++i) {
       sfm.insertNewFiles(al(createFile()));
     }
     for (int i = 0; i < filesInStripe; ++i) {
       ArrayList<StoreFile> stripe = new ArrayList<StoreFile>();
       for (int j = 0; j < stripes; ++j) {
         stripe.add(createFile(
             (j == 0) ? OPEN_KEY : keys[j - 1], (j == stripes - 1) ? OPEN_KEY : keys[j]));
       }
       sfm.addCompactionResults(al(), stripe);
     }
     assertEquals(expectedPriority, sfm.getStoreCompactionPriority());
   }
 
   private void verifyInvalidCompactionScenario(StripeStoreFileManager manager,
       ArrayList<StoreFile> filesToCompact, ArrayList<StoreFile> filesToInsert) throws Exception {
     Collection<StoreFile> allFiles = manager.getStorefiles();
     try {
        manager.addCompactionResults(filesToCompact, filesToInsert);
        fail("Should have thrown");
     } catch (IOException ex) {
       // Ignore it.
     }
     verifyAllFiles(manager, allFiles); // must have the same files.
   }
 
   private void verifyGetOrScanScenario(StripeStoreFileManager manager, boolean isGet,
       byte[] start, byte[] end, StoreFile... results) throws Exception {
     verifyGetOrScanScenario(manager, isGet, start, end, Arrays.asList(results));
   }
 
   private void verifyGetOrScanScenario(StripeStoreFileManager manager, boolean isGet,
       byte[] start, byte[] end, Collection<StoreFile> results) throws Exception {
     start = start != null ? start : HConstants.EMPTY_START_ROW;
     end = end != null ? end : HConstants.EMPTY_END_ROW;
     Collection<StoreFile> sfs = manager.getFilesForScanOrGet(start, true, end, true);
     assertEquals(results.size(), sfs.size());
     for (StoreFile result : results) {
       assertTrue(sfs.contains(result));
     }
   }
 
   private void verifyAllFiles(
       StripeStoreFileManager manager, Collection<StoreFile> results) throws Exception {
     verifyGetOrScanScenario(manager, false, null, null, results);
   }
 
   // TODO: replace with Mockito?
   private static MockStoreFile createFile(
       long size, long seqNum, byte[] startKey, byte[] endKey) throws Exception {
     FileSystem fs = TEST_UTIL.getTestFileSystem();
     Path testFilePath = StoreFile.getUniqueFile(fs, CFDIR);
     fs.create(testFilePath).close();
     MockStoreFile sf = new MockStoreFile(TEST_UTIL, testFilePath, size, 0, false, seqNum);
     if (startKey != null) {
       sf.setMetadataValue(StripeStoreFileManager.STRIPE_START_KEY, startKey);
     }
     if (endKey != null) {
       sf.setMetadataValue(StripeStoreFileManager.STRIPE_END_KEY, endKey);
     }
     return sf;
   }
 
   private static MockStoreFile createFile(long size, long seqNum) throws Exception {
     return createFile(size, seqNum, null, null);
   }
 
   private static MockStoreFile createFile(byte[] startKey, byte[] endKey) throws Exception {
     return createFile(0, 0, startKey, endKey);
   }
 
   private static MockStoreFile createFile() throws Exception {
     return createFile(null, null);
   }
 
   private static StripeStoreFileManager createManager() throws Exception {
     return createManager(new ArrayList<StoreFile>());
   }
 
   private static StripeStoreFileManager createManager(ArrayList<StoreFile> sfs) throws Exception {
     return createManager(sfs, TEST_UTIL.getConfiguration());
   }
 
   private static StripeStoreFileManager createManager(
       ArrayList<StoreFile> sfs, Configuration conf) throws Exception {
     StripeStoreConfig config = new StripeStoreConfig(
         conf, Mockito.mock(StoreConfigInformation.class));
     StripeStoreFileManager result = new StripeStoreFileManager(new KVComparator(), conf, config);
     result.loadFiles(sfs);
     return result;
   }
 
   private static ArrayList<StoreFile> al(StoreFile... sfs) {
     return new ArrayList<StoreFile>(Arrays.asList(sfs));
   }
 
   private static ArrayList<StoreFile> flattenLists(ArrayList<StoreFile>... sfls) {
     ArrayList<StoreFile> result = new ArrayList<StoreFile>();
     for (ArrayList<StoreFile> sfl : sfls) {
       result.addAll(sfl);
     }
     return result;
   }
 }