com.google.common.collect.MapDifference#entriesOnlyOnLeft ( )源码实例Demo

private CubeAssignment reassignCubeImpl(String cubeName, CubeAssignment preAssignments,
        CubeAssignment newAssignments) {
    logger.info("start cube reBalance, cube:{}, previous assignments:{}, new assignments:{}", cubeName,
            preAssignments, newAssignments);
    if (newAssignments.equals(preAssignments)) {
        logger.info("the new assignment is the same as the previous assignment, do nothing for this reassignment");
        return newAssignments;
    }
    CubeInstance cubeInstance = CubeManager.getInstance(KylinConfig.getInstanceFromEnv()).getCube(cubeName);
    doReassign(cubeInstance, preAssignments, newAssignments);
    MapDifference<Integer, List<Partition>> assignDiff = Maps.difference(preAssignments.getAssignments(),
            newAssignments.getAssignments());

    // add empty partitions to the removed replica sets, means that there's still data in the replica set, but no new data will be consumed.
    Map<Integer, List<Partition>> removedAssign = assignDiff.entriesOnlyOnLeft();
    for (Integer removedReplicaSet : removedAssign.keySet()) {
        newAssignments.addAssignment(removedReplicaSet, Lists.<Partition> newArrayList());
    }
    streamMetadataStore.saveNewCubeAssignment(newAssignments);
    AssignmentsCache.getInstance().clearCubeCache(cubeName);
    return newAssignments;
}
 

@NotAtomicAndNotIdempotent
void reassignCubeImpl(String cubeName, CubeAssignment preAssignments, CubeAssignment newAssignments) {
    logger.info("start cube reBalance, cube:{}, previous assignments:{}, new assignments:{}", cubeName,
            preAssignments, newAssignments);
    if (newAssignments.equals(preAssignments)) {
        logger.info("the new assignment is the same as the previous assignment, do nothing for this reassignment");
        return;
    }
    CubeInstance cubeInstance = getCoordinator().getCubeManager().getCube(cubeName);
    doReassignWithoutCommit(cubeInstance, preAssignments, newAssignments);

    // add empty partitions to the removed replica sets, means that there's still data in the replica set, but no new data will be consumed.
    MapDifference<Integer, List<Partition>> assignDiff = Maps.difference(preAssignments.getAssignments(),
            newAssignments.getAssignments());
    Map<Integer, List<Partition>> removedAssign = assignDiff.entriesOnlyOnLeft();
    for (Integer removedReplicaSet : removedAssign.keySet()) {
        newAssignments.addAssignment(removedReplicaSet, Lists.<Partition> newArrayList());
    }

    logger.info("Commit reassign {} transaction.", cubeName);
    getCoordinator().getStreamMetadataStore().saveNewCubeAssignment(newAssignments);
    AssignmentsCache.getInstance().clearCubeCache(cubeName);
}
 

@Test
public void givenDifferentMaps_whenGetEntriesOnOneSideUsingGuava_thenSuccess() {
    Map<String, String> asia1 = new HashMap<String, String>();
    asia1.put("Japan", "Tokyo");
    asia1.put("South Korea", "Seoul");
    asia1.put("India", "New Delhi");

    Map<String, String> asia2 = new HashMap<String, String>();
    asia2.put("Japan", "Tokyo");
    asia2.put("China", "Beijing");
    asia2.put("India", "Delhi");

    MapDifference<String, String> diff = Maps.difference(asia1, asia2);
    Map<String, String> entriesOnlyOnRight = diff.entriesOnlyOnRight();
    Map<String, String> entriesOnlyOnLeft = diff.entriesOnlyOnLeft();

    assertEquals(1, entriesOnlyOnRight.size());
    assertThat(entriesOnlyOnRight, hasEntry("China", "Beijing"));
    assertEquals(1, entriesOnlyOnLeft.size());
    assertThat(entriesOnlyOnLeft, hasEntry("South Korea", "Seoul"));
}
 

public static void safeUpdateByUpdateOrder(Map t, Map updateInfo) {
    MapDifference difference = Maps.difference(updateInfo, t);
    Map commonMap = difference.entriesInCommon();//求交集,交集为可以持续提供服务的数据源
    t.putAll(commonMap);
    Map entriesOnlyOnLeft = difference.entriesOnlyOnLeft();//两个map，左边有，右边没有的entry,为需要移除的数据源
    for (Object s : entriesOnlyOnLeft.keySet()) {
        t.remove(s);
    }
    t.putAll(updateInfo);
}
 

public Map<String, String> getAvailableNamedIds(NameIdConfig config) {
	MapDifference<String, String> diff = Maps.difference(availableNamedIds, usedNamedIds);
	Map<String, String> value = diff.entriesOnlyOnLeft();
	Map<String, String> result = Maps.newHashMap(value);
	if (config.getNameIdType() != null) {
		result.put(config.getNameIdType(), config.getNameIdType());
	}
	return result;
}
 

@Test
public void entries_only_on_left() {

	MapDifference<Integer, Student> mapDifference = Maps.difference(
			geometryClass, gymClass);

	Map<Integer, Student> studentsOnLeft = mapDifference
			.entriesOnlyOnLeft();

	logger.info(studentsOnLeft);

	assertThat(studentsOnLeft, hasKey(new Integer(456)));
	assertThat(studentsOnLeft, hasKey(new Integer(912)));
}
 

/**
 * @return the difference between oldProps and newProps.
 */
public static String getPropertyDiff(Props oldProps, Props newProps) {

  final StringBuilder builder = new StringBuilder("");

  // oldProps can not be null during the below comparison process.
  if (oldProps == null) {
    oldProps = new Props();
  }

  if (newProps == null) {
    newProps = new Props();
  }

  final MapDifference<String, String> md =
      Maps.difference(toStringMap(oldProps, false), toStringMap(newProps, false));

  final Map<String, String> newlyCreatedProperty = md.entriesOnlyOnRight();
  if (newlyCreatedProperty != null && newlyCreatedProperty.size() > 0) {
    builder.append("Newly created Properties: ");
    newlyCreatedProperty.forEach((k, v) -> {
      builder.append("[ " + k + ", " + v + "], ");
    });
    builder.append("\n");
  }

  final Map<String, String> deletedProperty = md.entriesOnlyOnLeft();
  if (deletedProperty != null && deletedProperty.size() > 0) {
    builder.append("Deleted Properties: ");
    deletedProperty.forEach((k, v) -> {
      builder.append("[ " + k + ", " + v + "], ");
    });
    builder.append("\n");
  }

  final Map<String, MapDifference.ValueDifference<String>> diffProperties = md.entriesDiffering();
  if (diffProperties != null && diffProperties.size() > 0) {
    builder.append("Modified Properties: ");
    diffProperties.forEach((k, v) -> {
      builder.append("[ " + k + ", " + v.leftValue() + "-->" + v.rightValue() + "], ");
    });
  }
  return builder.toString();
}