import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Tests to make sure a given layout version supports all the
 * features from the ancestor
 */
@Test
public void testFeaturesFromAncestorSupported() {
  for (LayoutFeature f : Feature.values()) {
    validateFeatureList(f);
  }
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Test to make sure NameNode.Feature support previous features
 */
@Test
public void testNameNodeFeature() {
  final LayoutFeature first = NameNodeLayoutVersion.Feature.ROLLING_UPGRADE; 
  assertTrue(NameNodeLayoutVersion.supports(LAST_NON_RESERVED_COMMON_FEATURE,
      first.getInfo().getLayoutVersion()));
  assertEquals(LAST_COMMON_FEATURE.getInfo().getLayoutVersion() - 1,
      first.getInfo().getLayoutVersion());
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Test to make sure DataNode.Feature support previous features
 */
@Test
public void testDataNodeFeature() {
  final LayoutFeature first = DataNodeLayoutVersion.Feature.FIRST_LAYOUT; 
  assertTrue(DataNodeLayoutVersion.supports(LAST_NON_RESERVED_COMMON_FEATURE,
      first.getInfo().getLayoutVersion()));
  assertEquals(LAST_COMMON_FEATURE.getInfo().getLayoutVersion() - 1,
      first.getInfo().getLayoutVersion());
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Given feature {@code f}, ensures the layout version of that feature
 * supports all the features supported by it's ancestor.
 */
private void validateFeatureList(LayoutFeature f) {
  final FeatureInfo info = f.getInfo();
  int lv = info.getLayoutVersion();
  int ancestorLV = info.getAncestorLayoutVersion();
  SortedSet<LayoutFeature> ancestorSet = NameNodeLayoutVersion.getFeatures(ancestorLV);
  assertNotNull(ancestorSet);
  for (LayoutFeature  feature : ancestorSet) {
    assertTrue("LV " + lv + " does nto support " + feature
        + " supported by the ancestor LV " + info.getAncestorLayoutVersion(),
        NameNodeLayoutVersion.supports(feature, lv));
  }
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Tests that NameNode features are listed in order of minimum compatible
 * layout version.  It would be inconsistent to have features listed out of
 * order with respect to minimum compatible layout version, because it would
 * imply going back in time to change compatibility logic in a software release
 * that had already shipped.
 */
@Test
public void testNameNodeFeatureMinimumCompatibleLayoutVersionAscending() {
  LayoutFeature prevF = null;
  for (LayoutFeature f : EnumSet.allOf(NameNodeLayoutVersion.Feature.class)) {
    if (prevF != null) {
      assertTrue(String.format("Features %s and %s not listed in order of " +
          "minimum compatible layout version.", prevF, f),
          f.getInfo().getMinimumCompatibleLayoutVersion() <=
          prevF.getInfo().getMinimumCompatibleLayoutVersion());
    } else {
      prevF = f;
    }
  }
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
/**
 * Tests that attempting to add a new NameNode feature out of order with
 * respect to minimum compatible layout version will fail fast.
 */
@Test(expected=AssertionError.class)
public void testNameNodeFeatureMinimumCompatibleLayoutVersionOutOfOrder() {
  FeatureInfo ancestorF = LayoutVersion.Feature.RESERVED_REL2_4_0.getInfo();
  LayoutFeature f = mock(LayoutFeature.class);
  when(f.getInfo()).thenReturn(new FeatureInfo(
      ancestorF.getLayoutVersion() - 1, ancestorF.getLayoutVersion(),
      ancestorF.getMinimumCompatibleLayoutVersion() + 1, "Invalid feature.",
      false));
  Map<Integer, SortedSet<LayoutFeature>> features = new HashMap<>();
  LayoutVersion.updateMap(features, LayoutVersion.Feature.values());
  LayoutVersion.updateMap(features, new LayoutFeature[] { f });
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
public static SortedSet<LayoutFeature> getFeatures(int lv) {
  return FEATURES.get(lv);
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
public static boolean supports(final LayoutFeature f, final int lv) {
  return LayoutVersion.supports(FEATURES, f, lv);
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
public boolean versionSupportsFederation(
    Map<Integer, SortedSet<LayoutFeature>> map) {
  return LayoutVersion.supports(map, LayoutVersion.Feature.FEDERATION,
      layoutVersion);
}
 

import org.apache.hadoop.hdfs.protocol.LayoutVersion.LayoutFeature; //导入依赖的package包/类
public Map<Integer, SortedSet<LayoutFeature>> getServiceLayoutFeatureMap() {
  return storageType == NodeType.DATA_NODE? DataNodeLayoutVersion.FEATURES
      : NameNodeLayoutVersion.FEATURES;
}