Example usage for com.amazonaws.services.dynamodbv2.model KeysAndAttributes setAttributesToGet

Introduction

In this page you can find the example usage for com.amazonaws.services.dynamodbv2.model KeysAndAttributes setAttributesToGet.

Prototype

public void setAttributesToGet(java.util.Collection<String> attributesToGet) 

Source Link

Document

This is a legacy parameter.

Usage

From source file:com.erudika.para.persistence.AWSDynamoDAO.java

License:Apache License

@Override
public <P extends ParaObject> Map<String, P> readAll(String appid, List<String> keys, boolean getAllColumns) {
    if (keys == null || keys.isEmpty() || StringUtils.isBlank(appid)) {
        return new LinkedHashMap<String, P>();
    }/*from   w ww .  j  av a2s  .  c  om*/

    // DynamoDB doesn't allow duplicate keys in batch requests
    Set<String> keySet = new TreeSet<String>(keys);
    if (keySet.size() < keys.size() && !keySet.isEmpty()) {
        logger.debug("Duplicate keys found - readAll({})", keys);
    }

    Map<String, P> results = new LinkedHashMap<String, P>(keySet.size(), 0.75f, true);
    ArrayList<Map<String, AttributeValue>> keyz = new ArrayList<Map<String, AttributeValue>>(MAX_KEYS_PER_READ);

    try {
        int batchSteps = 1;
        if ((keySet.size() > MAX_KEYS_PER_READ)) {
            batchSteps = (keySet.size() / MAX_KEYS_PER_READ)
                    + ((keySet.size() % MAX_KEYS_PER_READ > 0) ? 1 : 0);
        }

        Iterator<String> it = keySet.iterator();
        int j = 0;

        for (int i = 0; i < batchSteps; i++) {
            while (it.hasNext() && j < MAX_KEYS_PER_READ) {
                String key = it.next();
                results.put(key, null);
                keyz.add(Collections.singletonMap(Config._KEY, new AttributeValue(getKeyForAppid(key, appid))));
                j++;
            }

            KeysAndAttributes kna = new KeysAndAttributes().withKeys(keyz);
            if (!getAllColumns) {
                kna.setAttributesToGet(Arrays.asList(Config._KEY, Config._TYPE));
            }

            batchGet(Collections.singletonMap(getTableNameForAppid(appid), kna), results);
            keyz.clear();
            j = 0;
        }
        logger.debug("DAO.readAll({}) {}", keySet, results.size());
    } catch (Exception e) {
        logger.error("Failed to readAll({}), {}", keys, e);
    }
    return results;
}

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