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From ctubbsii <...@git.apache.org>
Subject [GitHub] accumulo pull request #279: ACCUMULO-3238 Table.ID Namespace.ID Refactor
Date Tue, 11 Jul 2017 17:43:38 GMT
Github user ctubbsii commented on a diff in the pull request:

    https://github.com/apache/accumulo/pull/279#discussion_r126759594
  
    --- Diff: core/src/main/java/org/apache/accumulo/core/client/impl/Namespaces.java ---
    @@ -100,50 +106,150 @@ private static ZooCache getZooCache(Instance instance) {
         return namespaceMap;
       }
     
    -  public static boolean exists(Instance instance, String namespaceId) {
    +  public static boolean exists(Instance instance, Namespace.ID namespaceId) {
         ZooCache zc = getZooCache(instance);
         List<String> namespaceIds = zc.getChildren(ZooUtil.getRoot(instance) + Constants.ZNAMESPACES);
    -    return namespaceIds.contains(namespaceId);
    -  }
    -
    -  public static String getNamespaceId(Instance instance, String namespace) throws NamespaceNotFoundException
{
    -    String id = getNameToIdMap(instance).get(namespace);
    -    if (id == null)
    -      throw new NamespaceNotFoundException(null, namespace, "getNamespaceId() failed
to find namespace");
    -    return id;
    +    return namespaceIds.contains(namespaceId.canonicalID());
       }
     
    +  /**
    +   * @deprecated Do not use - String for namespace ID is not type safe. Use {@link #getNamespaceName(Instance,
Namespace.ID)}
    +   */
    +  @Deprecated
       public static String getNamespaceName(Instance instance, String namespaceId) throws
NamespaceNotFoundException {
         String namespaceName = getIdToNameMap(instance).get(namespaceId);
         if (namespaceName == null)
           throw new NamespaceNotFoundException(namespaceId, null, "getNamespaceName() failed
to find namespace");
         return namespaceName;
       }
     
    +  /**
    +   * @deprecated Do not use - Not type safe, ambiguous String-String map. Use {@link
#getNameMap(Instance)}
    +   */
    +  @Deprecated
       public static SortedMap<String,String> getNameToIdMap(Instance instance) {
         return getMap(instance, true);
       }
     
    +  /**
    +   * @deprecated Do not use - Not type safe, ambiguous String-String map. Use {@link
#getIdMap(Instance)}
    +   */
    +  @Deprecated
       public static SortedMap<String,String> getIdToNameMap(Instance instance) {
         return getMap(instance, false);
       }
     
    -  public static List<String> getTableIds(Instance instance, String namespaceId)
throws NamespaceNotFoundException {
    +  public static List<Table.ID> getTableIds(Instance instance, Namespace.ID namespaceId)
throws NamespaceNotFoundException {
         String namespace = getNamespaceName(instance, namespaceId);
    -    List<String> names = new LinkedList<>();
    -    for (Entry<String,String> nameToId : Tables.getNameToIdMap(instance).entrySet())
    +    List<Table.ID> tableIds = new LinkedList<>();
    +    for (Entry<String,Table.ID> nameToId : Tables.getNameMap(instance).entrySet())
           if (namespace.equals(Tables.qualify(nameToId.getKey()).getFirst()))
    -        names.add(nameToId.getValue());
    -    return names;
    +        tableIds.add(nameToId.getValue());
    +    return tableIds;
       }
     
    -  public static List<String> getTableNames(Instance instance, String namespaceId)
throws NamespaceNotFoundException {
    +  public static List<String> getTableNames(Instance instance, Namespace.ID namespaceId)
throws NamespaceNotFoundException {
         String namespace = getNamespaceName(instance, namespaceId);
         List<String> names = new LinkedList<>();
    -    for (String name : Tables.getNameToIdMap(instance).keySet())
    +    for (String name : Tables.getNameMap(instance).keySet())
           if (namespace.equals(Tables.qualify(name).getFirst()))
             names.add(name);
         return names;
       }
     
    +  /**
    +   * Populate map passed in as the BiConsumer. key = ID, value = namespaceName
    +   */
    +  private static void populateMap(Instance instance, BiConsumer<String,String>
biConsumer) {
    +    final ZooCache zc = getZooCache(instance);
    +    List<String> namespaceIds = zc.getChildren(ZooUtil.getRoot(instance) + Constants.ZNAMESPACES);
    +    for (String id : namespaceIds) {
    +      byte[] path = zc.get(ZooUtil.getRoot(instance) + Constants.ZNAMESPACES + "/" +
id + Constants.ZNAMESPACE_NAME);
    +      if (path != null) {
    +        biConsumer.accept(id, new String(path, UTF_8));
    +      }
    +    }
    +  }
    +
    +  /**
    +   * Return sorted map with key = ID, value = namespaceName
    +   */
    +  public static SortedMap<Namespace.ID,String> getIdMap(Instance instance) {
    +    SortedMap<Namespace.ID,String> idMap = new TreeMap<>();
    +    populateMap(instance, (id, name) -> idMap.put(new Namespace.ID(id), name));
    +    return idMap;
    +  }
    +
    +  /**
    +   * Return sorted map with key = namespaceName, value = ID
    +   */
    +  public static SortedMap<String,Namespace.ID> getNameMap(Instance instance) {
    +    SortedMap<String,Namespace.ID> nameMap = new TreeMap<>();
    +    populateMap(instance, (id, name) -> nameMap.put(name, new Namespace.ID(id)));
    +    return nameMap;
    +  }
    +
    +  /**
    +   * Look for namespace ID in ZK. Throw NamespaceNotFoundException if not found.
    +   */
    +  public static Namespace.ID getNamespaceId(Instance instance, String namespaceName)
throws NamespaceNotFoundException {
    +    final ArrayList<Namespace.ID> singleId = new ArrayList<>(1);
    +    populateMap(instance, (id, name) -> {
    +      if (name.equals(namespaceName))
    +        singleId.add(new Namespace.ID(id));
    +    });
    +    if (singleId.isEmpty())
    +      throw new NamespaceNotFoundException(null, namespaceName, "getNamespaceId() failed
to find namespace");
    +    return singleId.get(0);
    +  }
    +
    +  /**
    +   * Look for namespace ID in ZK. Fail quietly by logging and returning null.
    +   */
    +  public static Namespace.ID lookupNamespaceId(Instance instance, String namespaceName)
{
    +    Namespace.ID id = null;
    +    try {
    +      id = getNamespaceId(instance, namespaceName);
    +    } catch (NamespaceNotFoundException e) {
    +      if (log.isDebugEnabled())
    +        log.debug("Failed to find namespace ID from name: " + namespaceName, e);
    +    }
    +    return id;
    +  }
    +
    +  /**
    +   * Return true if namespace name exists
    +   */
    +  public static boolean namespaceNameExists(Instance instance, String namespaceName)
{
    +    return lookupNamespaceId(instance, namespaceName) != null;
    +  }
    +
    +  /**
    +   * Look for namespace name in ZK. Throw NamespaceNotFoundException if not found.
    +   */
    +  public static String getNamespaceName(Instance instance, Namespace.ID namespaceId)
throws NamespaceNotFoundException {
    +    final ArrayList<String> singleName = new ArrayList<>(1);
    +    populateMap(instance, (id, name) -> {
    +      if (id.equals(namespaceId.canonicalID()))
    +        singleName.add(name);
    +    });
    +    if (singleName.isEmpty())
    +      throw new NamespaceNotFoundException(namespaceId.canonicalID(), null, "getNamespaceName()
failed to find namespace");
    +    return singleName.get(0);
    +  }
    +
    +  /**
    +   * Look for namespace name in ZK. Fail quietly by logging and returning null.
    +   */
    +  public static String lookupNamespaceName(Instance instance, Namespace.ID namespaceId)
{
    +    String name = null;
    +    try {
    +      getNamespaceName(instance, namespaceId);
    --- End diff --
    
    I don't think this is something @milleruntime  added. It probably already existed. I think
this kind of thing plagues the whole of `Tables` and `Namespaces` util classes. These were
intended for very specific internal use cases, with very specific handling behaviors, and
in some cases, warnings were suppressed from common code because the caller had its own handling
(possibly with better messages).
    
    Over time, these util methods got used for things they were not originally intended to
be used for. It's possible some of the callers depend on the null return value, and others
would benefit from the exception being thrown. Without actually tracing all the callers, it's
anyone's guess as to how many of these util classes are being used with incorrect assumptions
about exception handling. I seem to recall at least a few bugs being fixed because of this.


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