Java 类com.amazonaws.services.dynamodbv2.document.QueryOutcome 实例源码

/**
 * Reads a page from a "shared" DynamoDB table. Shared tables are tables that have global secondary indexes
 * and can contain the objects of multiple apps.
 * @param <P> type of object
 * @param appid the app identifier (name)
 * @param pager a {@link Pager}
 * @return the id of the last object on the page, or null.
 */
public static <P extends ParaObject> List<P> readPageFromSharedTable(String appid, Pager pager) {
    LinkedList<P> results = new LinkedList<>();
    if (StringUtils.isBlank(appid)) {
        return results;
    }
    Page<Item, QueryOutcome> items = queryGSI(appid, pager);
    if (items != null) {
        for (Item item : items) {
            P obj = ParaObjectUtils.setAnnotatedFields(item.asMap());
            if (obj != null) {
                results.add(obj);
            }
        }
    }
    if (!results.isEmpty() && pager != null) {
        pager.setLastKey(results.peekLast().getId());
    }
    return results;
}

private static Page<Item, QueryOutcome> queryGSI(String appid, Pager p) {
    Pager pager = (p != null) ? p : new Pager();
    Index index = getSharedIndex();
    QuerySpec spec = new QuerySpec().
            withMaxPageSize(pager.getLimit()).
            withMaxResultSize(pager.getLimit()).
            withKeyConditionExpression(Config._APPID + " = :aid").
            withValueMap(new ValueMap().withString(":aid", appid));

    if (!StringUtils.isBlank(pager.getLastKey())) {
        spec = spec.withExclusiveStartKey(new KeyAttribute(Config._APPID, appid),   // HASH/PARTITION KEY
                new KeyAttribute(Config._ID, pager.getLastKey()), // RANGE/SORT KEY
                new KeyAttribute(Config._KEY, getKeyForAppid(pager.getLastKey(), appid))); // TABLE PRIMARY KEY
    }
    return index != null ? index.query(spec).firstPage() : null;
}

private static void findRepliesUsingAFilterExpression(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id")
            .withFilterExpression("PostedBy = :v_postedby")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_postedby", "User B"));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesUsingAFilterExpression results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
     }

@Override public boolean queryRelationExists(String relationHashKey, String relationRangeKey) {

    Table table = dynamoDB.getTable(this.groupGraphTableName);

    QuerySpec querySpec = new QuerySpec()
        .withKeyConditionExpression("subject = :k_subject and object_relation = :k_object_relation")
        .withValueMap(new ValueMap()
            .withString(":k_subject", relationHashKey)
            .withString(":k_object_relation", relationRangeKey)
        )
        .withMaxResultSize(1)
        .withConsistentRead(true);

    DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("queryRelation",
        () -> queryTable(table, querySpec),
        () -> {
          throw new RuntimeException("queryRelation");
        },
        dynamodbNamespaceGraphQueryHystrix,
        metrics);

    // can't use getLastLowLevelResult directly; it's false unless the outcome is iterated first :|
    return cmd.execute().iterator().hasNext();
  }

@Override public Optional<Group> loadByKey(String key) {
  Table table = dynamoDB.getTable(this.groupTableName);

  QuerySpec querySpec = new QuerySpec()
      .withKeyConditionExpression(HASH_KEY + " = :k_app_key")
      .withValueMap(new ValueMap()
          .withString(":k_app_key", key)
      )
      .withMaxResultSize(1)
      .withConsistentRead(true);

  DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("loadByKey",
      () -> queryTable(table, querySpec),
      () -> {
        throw new RuntimeException("loadByKey");
      },
      dynamodbNamespaceGraphQueryHystrix,
      metrics);

  final ItemCollection<QueryOutcome> items = cmd.execute();
  final IteratorSupport<Item, QueryOutcome> iterator = items.iterator();
  if (iterator.hasNext()) {
    return Optional.of(GroupSupport.toGroup(iterator.next().getString("json")));
  }

  return Optional.empty();
}

@Override public List<Feature> loadFeatures(String group) {
  logger.info("{}", kvp("op", "loadFeatures", "group", group));
  List<Feature> features = Lists.newArrayList();

  Table table = dynamoDB.getTable(featureTableName);

  QuerySpec querySpec = new QuerySpec()
      .withKeyConditionExpression(HASH_KEY + " = :k_" + HASH_KEY)
      .withValueMap(new ValueMap().withString(":k_" + HASH_KEY, group))
      .withConsistentRead(true);

  DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("loadFeatures",
      () -> queryTable(table, querySpec),
      () -> {
        throw new RuntimeException("loadFeatureById");
      },
      hystrixReadConfiguration,
      metrics);

  ItemCollection<QueryOutcome> items = cmd.execute();

  for (Page<Item, QueryOutcome> page : items.pages()) {
    page.forEach(item -> features.add(FeatureSupport.toFeature(item.getString("json"))));
  }

  return features;
}

private <V> List<V> toList(QueryOutcome outcome, Class<V> type) {
    List<Item> items = outcome.getItems();
    List<V> result = new ArrayList<V>(items.size());
    for ( Item item : items ) {
        result.add(fromItem(_encryption.decrypt(item), type));
    }
    return Collections.unmodifiableList(result);
}

private QueryOutcome query(Object hk, QuerySpec querySpec, PageIterator pageIterator) {
    if ( null == _convertMarker ) {
        throw new IllegalStateException("Index must first be initialized with ConvertMarker");
    }
    if ( pageIterator.getPageSize() <= 0 ) {
        return new QueryOutcome(new QueryResult());
    }
    ItemCollection<QueryOutcome> itemCollection =
        maybeBackoff(true, () ->
                     _query.query(withMarker(querySpec.withHashKey(_hkName, hk), pageIterator, hk)));

    if ( null != itemCollection ) {
        Iterator<Page<Item, QueryOutcome>> iterator = itemCollection.pages().iterator();
        if ( iterator.hasNext() ) {
            QueryOutcome outcome = maybeBackoff(true, () -> iterator.next().getLowLevelResult());
            QueryResult result = outcome.getQueryResult();
            if ( null != pageIterator.getMarker() && null != result.getItems() && result.getItems().size() > 0 ) {
                pageIterator.setPrevMarker(toMarker(result.getItems().get(0), true));
            } else {
                pageIterator.setPrevMarker(null);
            }
            Map<String,AttributeValue> lastKey = result.getLastEvaluatedKey();
            if ( null != lastKey && ! lastKey.isEmpty() ) {
                pageIterator.setMarker(toMarker(lastKey, true));
            } else {
                pageIterator.setMarker(null);
            }
            return outcome;
        }
    }
    pageIterator.setPrevMarker(null);
    pageIterator.setMarker(null);
    return new QueryOutcome(new QueryResult());
}

private static void findRepliesInLast15DaysWithConfig(
    String tableName, String forumName, String threadSubject) {

    String replyId = forumName + "#" + threadSubject;
    long twoWeeksAgoMilli = (new Date()).getTime()
        - (15L * 24L * 60L * 60L * 1000L);
    Date twoWeeksAgo = new Date();
    twoWeeksAgo.setTime(twoWeeksAgoMilli);
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    String twoWeeksAgoStr = df.format(twoWeeksAgo);

    Table table = dynamoDB.getTable(tableName);

    QuerySpec querySpec = new QuerySpec()
        .withKeyConditionExpression("Id = :v1 and ReplyDateTime > :v2")
        .withValueMap(new ValueMap()
            .withString(":v1", replyId)
            .withString(":v2", twoWeeksAgoStr))
        .withProjectionExpression("Message, ReplyDateTime, PostedBy");

    ItemCollection<QueryOutcome> items = table.query(querySpec);
    Iterator<Item> iterator = items.iterator();

    System.out.println("Query: printing results...");

    while (iterator.hasNext()) {
        System.out.println(iterator.next().toJSONPretty());
    }
}

private static void findRepliesForAThreadSpecifyOptionalLimit(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;   

        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId))
            .withMaxPageSize(1);

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesForAThreadSpecifyOptionalLimit results:");

        // Process each page of results
        int pageNum = 0;
        for (Page<Item, QueryOutcome> page : items.pages()) {

            System.out.println("\nPage: " + ++pageNum);

            // Process each item on the current page
            Iterator<Item> item = page.iterator();
            while (item.hasNext()) {
                System.out.println(item.next().toJSONPretty());
            }
        }
    }

private static void findRepliesInLast15DaysWithConfig(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long twoWeeksAgoMilli = (new Date()).getTime() - (15L*24L*60L*60L*1000L);
        Date twoWeeksAgo = new Date();
        twoWeeksAgo.setTime(twoWeeksAgoMilli);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String twoWeeksAgoStr = df.format(twoWeeksAgo);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime <= :v_reply_dt_tm")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_reply_dt_tm", twoWeeksAgoStr));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesInLast15DaysWithConfig results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }

private static void findRepliesPostedWithinTimePeriod(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long startDateMilli = (new Date()).getTime() - (15L*24L*60L*60L*1000L); 
        long endDateMilli = (new Date()).getTime() - (5L*24L*60L*60L*1000L);    
        java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String startDate = df.format(startDateMilli);
        String endDate = df.format(endDateMilli);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime between :v_start_dt and :v_end_dt")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_start_dt", startDate)
                .withString(":v_end_dt", endDate));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesPostedWithinTimePeriod results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
    }

public MAVLinkRecordIterable(IteratorSupport<Item, QueryOutcome> it) {
    this.itemIterator = it;
}

private ItemCollection<QueryOutcome> queryTable(Table table, QuerySpec querySpec) {
  return table.query(querySpec);
}

private ItemCollection<QueryOutcome> queryTable(Table table, QuerySpec querySpec) {
  return table.query(querySpec);
}

private static int toCount(QueryOutcome outcome) {
    Integer result = outcome.getQueryResult().getCount();
    return ( null == result ) ? 0 : result.intValue();
}

private List<T> toList(QueryOutcome outcome) {
    return toList(outcome, _clazz);
}

/**
 * Deletes all objects in a shared table, which belong to a given appid, by scanning the GSI.
 * @param appid app id
 */
public static void deleteAllFromSharedTable(String appid) {
    if (StringUtils.isBlank(appid) || !isSharedAppid(appid)) {
        return;
    }
    Pager pager = new Pager(50);
    List<WriteRequest> allDeletes = new LinkedList<>();
    Page<Item, QueryOutcome> items;
    // read all phase
    do {
        items = queryGSI(appid, pager);
        if (items == null) {
            break;
        }
        for (Item item : items) {
            String key = item.getString(Config._KEY);
            // only delete rows which belong to the given appid
            if (StringUtils.startsWith(key, appid.trim())) {
                logger.debug("Preparing to delete '{}' from shared table, appid: '{}'.", key, appid);
                pager.setLastKey(item.getString(Config._ID));
                allDeletes.add(new WriteRequest().withDeleteRequest(new DeleteRequest().
                        withKey(Collections.singletonMap(Config._KEY, new AttributeValue(key)))));
            }
        }
    } while (items.iterator().hasNext());

    // delete all phase
    final int maxItems = 20;
    int batchSteps = (allDeletes.size() > maxItems) ? (allDeletes.size() / maxItems) + 1 : 1;
    List<WriteRequest> reqs = new LinkedList<>();
    Iterator<WriteRequest> it = allDeletes.iterator();
    String tableName = getTableNameForAppid(appid);
    for (int i = 0; i < batchSteps; i++) {
        while (it.hasNext() && reqs.size() < maxItems) {
            reqs.add(it.next());
        }
        if (reqs.size() > 0) {
            logger.info("Deleting {} items belonging to app '{}', from shared table (page {}/{})...",
                    reqs.size(), appid, i + 1, batchSteps);
            batchWrite(Collections.singletonMap(tableName, reqs));
        }
        reqs.clear();
    }
}

public static void main(String[] args)  {

        AmazonDynamoDBClient client = new AmazonDynamoDBClient();
        client.setEndpoint("http://localhost:8000");
        DynamoDB dynamoDB = new DynamoDB(client);

        Table table = dynamoDB.getTable("Movies");

        HashMap<String, String> nameMap = new HashMap<String, String>();
        nameMap.put("#yr", "year"); 

        HashMap<String, Object> valueMap = new HashMap<String, Object>();
        valueMap.put(":yyyy", 1985);

        QuerySpec querySpec = new QuerySpec()
            .withKeyConditionExpression("#yr = :yyyy")
            .withNameMap(new NameMap().with("#yr", "year"))
            .withValueMap(valueMap);

        ItemCollection<QueryOutcome> items = table.query(querySpec);

        Iterator<Item> iterator = items.iterator();
        Item item = null;

        System.out.println("Movies from 1985");
        while (iterator.hasNext()) {
            item = iterator.next();
            System.out.println(item.getNumber("year") + ": " + item.getString("title"));
        }

        valueMap.put(":yyyy", 1992);
        valueMap.put(":letter1", "A");
        valueMap.put(":letter2", "L");

        querySpec
            .withProjectionExpression("#yr, title, info.genres, info.actors[0]")
            .withKeyConditionExpression("#yr = :yyyy and title between :letter1 and :letter2")
            .withNameMap(nameMap)
            .withValueMap(valueMap);

        items = table.query(querySpec);
        iterator = items.iterator();

        System.out.println("Movies from 1992 - titles A-L, with genres and lead actor");
        while (iterator.hasNext()) {
            item = iterator.next();
            System.out.println(item.toString());
        }

    }

private static void findRepliesForAThread(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesForAThread results:");

        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }

public static void queryIndex(String indexName) {

    Table table = dynamoDB.getTable(tableName);

    System.out.println
    ("\n***********************************************************\n");
    System.out.print("Querying index " + indexName + "...");

    Index index = table.getIndex(indexName);

    ItemCollection<QueryOutcome> items = null;

    QuerySpec querySpec = new QuerySpec();

    if (indexName == "CreateDateIndex") {
        System.out.println("Issues filed on 2013-11-01");
        querySpec.withKeyConditionExpression("CreateDate = :v_date and begins_with(IssueId, :v_issue)")
            .withValueMap(new ValueMap()
                .withString(":v_date","2013-11-01")
                .withString(":v_issue","A-"));
        items = index.query(querySpec);
    } else if (indexName == "TitleIndex") {
        System.out.println("Compilation errors");
        querySpec.withKeyConditionExpression("Title = :v_title and begins_with(IssueId, :v_issue)")
            .withValueMap(new ValueMap()
                .withString(":v_title","Compilation error")
                .withString(":v_issue","A-"));
        items = index.query(querySpec);
    } else if (indexName == "DueDateIndex") {
        System.out.println("Items that are due on 2013-11-30");
        querySpec.withKeyConditionExpression("DueDate = :v_date")
            .withValueMap(new ValueMap()
                .withString(":v_date","2013-11-30"));
        items = index.query(querySpec);
    } else {
        System.out.println("\nNo valid index name provided");
        return;
    }

    Iterator<Item> iterator = items.iterator();

    System.out.println("Query: printing results...");

    while (iterator.hasNext()) {
        System.out.println(iterator.next().toJSONPretty());
    }


}