import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
/**
 * Factory method that makes a new CacheDirectiveInfo by applying fields in a
 * CacheDirectiveInfo to an existing CacheDirective.
 * 
 * @param info with some or all fields set.
 * @param defaults directive providing default values for unset fields in
 *          info.
 * 
 * @return new CacheDirectiveInfo of the info applied to the defaults.
 */
private static CacheDirectiveInfo createFromInfoAndDefaults(
    CacheDirectiveInfo info, CacheDirective defaults) {
  // Initialize the builder with the default values
  CacheDirectiveInfo.Builder builder =
      new CacheDirectiveInfo.Builder(defaults.toInfo());
  // Replace default with new value if present
  if (info.getPath() != null) {
    builder.setPath(info.getPath());
  }
  if (info.getReplication() != null) {
    builder.setReplication(info.getReplication());
  }
  if (info.getPool() != null) {
    builder.setPool(info.getPool());
  }
  if (info.getExpiration() != null) {
    builder.setExpiration(info.getExpiration());
  }
  return builder.build();
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
private void removeInternal(CacheDirective directive)
    throws InvalidRequestException {
  assert namesystem.hasWriteLock();
  // Remove the corresponding entry in directivesByPath.
  String path = directive.getPath();
  List<CacheDirective> directives = directivesByPath.get(path);
  if (directives == null || !directives.remove(directive)) {
    throw new InvalidRequestException("Failed to locate entry " +
        directive.getId() + " by path " + directive.getPath());
  }
  if (directives.size() == 0) {
    directivesByPath.remove(path);
  }
  // Fix up the stats from removing the pool
  final CachePool pool = directive.getPool();
  directive.addBytesNeeded(-directive.getBytesNeeded());
  directive.addFilesNeeded(-directive.getFilesNeeded());

  directivesById.remove(directive.getId());
  pool.getDirectiveList().remove(directive);
  assert directive.getPool() == null;

  setNeedsRescan();
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
/**
 * Load cache directives from the fsimage
 */
private void loadDirectives(DataInput in) throws IOException {
  StartupProgress prog = NameNode.getStartupProgress();
  Step step = new Step(StepType.CACHE_ENTRIES);
  prog.beginStep(Phase.LOADING_FSIMAGE, step);
  int numDirectives = in.readInt();
  prog.setTotal(Phase.LOADING_FSIMAGE, step, numDirectives);
  Counter counter = prog.getCounter(Phase.LOADING_FSIMAGE, step);
  for (int i = 0; i < numDirectives; i++) {
    CacheDirectiveInfo info = FSImageSerialization.readCacheDirectiveInfo(in);
    // Get pool reference by looking it up in the map
    final String poolName = info.getPool();
    CacheDirective directive =
        new CacheDirective(info.getId(), info.getPath().toUri().getPath(),
            info.getReplication(), info.getExpiration().getAbsoluteMillis());
    addCacheDirective(poolName, directive);
    counter.increment();
  }
  prog.endStep(Phase.LOADING_FSIMAGE, step);
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
/**
 * Get a CacheDirective by ID, validating the ID and that the directive
 * exists.
 */
private CacheDirective getById(long id) throws InvalidRequestException {
  // Check for invalid IDs.
  if (id <= 0) {
    throw new InvalidRequestException("Invalid negative ID.");
  }
  // Find the directive.
  CacheDirective directive = directivesById.get(id);
  if (directive == null) {
    throw new InvalidRequestException("No directive with ID " + id
        + " found.");
  }
  return directive;
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
/**
 * Adds a directive, skipping most error checking. This should only be called
 * internally in special scenarios like edit log replay.
 */
CacheDirectiveInfo addDirectiveFromEditLog(CacheDirectiveInfo directive)
    throws InvalidRequestException {
  long id = directive.getId();
  CacheDirective entry = new CacheDirective(directive);
  CachePool pool = cachePools.get(directive.getPool());
  addInternal(entry, pool);
  if (nextDirectiveId <= id) {
    nextDirectiveId = id + 1;
  }
  return entry.toInfo();
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
/**
 * Modifies a directive, skipping most error checking. This is for careful
 * internal use only. modifyDirective can be non-deterministic since its error
 * checking depends on current system time, which poses a problem for edit log
 * replay.
 */
void modifyDirectiveFromEditLog(CacheDirectiveInfo info)
    throws InvalidRequestException {
  // Check for invalid IDs.
  Long id = info.getId();
  if (id == null) {
    throw new InvalidRequestException("Must supply an ID.");
  }
  CacheDirective prevEntry = getById(id);
  CacheDirectiveInfo newInfo = createFromInfoAndDefaults(info, prevEntry);
  removeInternal(prevEntry);
  addInternal(new CacheDirective(newInfo), getCachePool(newInfo.getPool()));
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
private void saveDirectives(DataOutputStream out, String sdPath)
    throws IOException {
  StartupProgress prog = NameNode.getStartupProgress();
  Step step = new Step(StepType.CACHE_ENTRIES, sdPath);
  prog.beginStep(Phase.SAVING_CHECKPOINT, step);
  prog.setTotal(Phase.SAVING_CHECKPOINT, step, directivesById.size());
  Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
  out.writeInt(directivesById.size());
  for (CacheDirective directive : directivesById.values()) {
    FSImageSerialization.writeCacheDirectiveInfo(out, directive.toInfo());
    counter.increment();
  }
  prog.endStep(Phase.SAVING_CHECKPOINT, step);
}
 

import org.apache.hadoop.hdfs.protocol.CacheDirective; //导入依赖的package包/类
private void resetStatistics() {
  for (CachePool pool: cacheManager.getCachePools()) {
    pool.resetStatistics();
  }
  for (CacheDirective directive: cacheManager.getCacheDirectives()) {
    directive.resetStatistics();
  }
}