import org.apache.hadoop.hbase.regionserver.MemStoreLAB.Allocation; //导入依赖的package包/类
/**
 * Test a bunch of random allocations
 */
@Test
public void testLABRandomAllocation() {
  Random rand = new Random();
  MemStoreLAB mslab = new MemStoreLAB();
  int expectedOff = 0;
  byte[] lastBuffer = null;
  // 100K iterations by 0-1K alloc -> 50MB expected
  // should be reasonable for unit test and also cover wraparound
  // behavior
  for (int i = 0; i < 100000; i++) {
    int size = rand.nextInt(1000);
    Allocation alloc = mslab.allocateBytes(size);
    
    if (alloc.getData() != lastBuffer) {
      expectedOff = 0;
      lastBuffer = alloc.getData();
    }
    assertEquals(expectedOff, alloc.getOffset());
    assertTrue("Allocation " + alloc + " overruns buffer",
        alloc.getOffset() + size <= alloc.getData().length);
    expectedOff += size;
  }
}
 

import org.apache.hadoop.hbase.regionserver.MemStoreLAB.Allocation; //导入依赖的package包/类
@Test
public void testLABLargeAllocation() {
  MemStoreLAB mslab = new MemStoreLAB();
  Allocation alloc = mslab.allocateBytes(2*1024*1024);
  assertNull("2MB allocation shouldn't be satisfied by LAB.",
    alloc);
}
 

import org.apache.hadoop.hbase.regionserver.MemStoreLAB.Allocation; //导入依赖的package包/类
@Test
public void testReusingChunks() {
  Random rand = new Random();
  MemStoreLAB mslab = new MemStoreLAB(conf, chunkPool);
  int expectedOff = 0;
  byte[] lastBuffer = null;
  // Randomly allocate some bytes
  for (int i = 0; i < 100; i++) {
    int size = rand.nextInt(1000);
    Allocation alloc = mslab.allocateBytes(size);

    if (alloc.getData() != lastBuffer) {
      expectedOff = 0;
      lastBuffer = alloc.getData();
    }
    assertEquals(expectedOff, alloc.getOffset());
    assertTrue("Allocation " + alloc + " overruns buffer", alloc.getOffset()
        + size <= alloc.getData().length);
    expectedOff += size;
  }
  // chunks will be put back to pool after close
  mslab.close();
  int chunkCount = chunkPool.getPoolSize();
  assertTrue(chunkCount > 0);
  // reconstruct mslab
  mslab = new MemStoreLAB(conf, chunkPool);
  // chunk should be got from the pool, so we can reuse it.
  mslab.allocateBytes(1000);
  assertEquals(chunkCount - 1, chunkPool.getPoolSize());
}
 

import org.apache.hadoop.hbase.regionserver.MemStoreLAB.Allocation; //导入依赖的package包/类
public AllocRecord(Allocation alloc, int size) {
  super();
  this.alloc = alloc;
  this.size = size;
}