Example usage for com.amazonaws.services.dynamodbv2.model ScanRequest withExclusiveStartKey

Introduction

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

Prototype

public ScanRequest withExclusiveStartKey(java.util.Map<String, AttributeValue> exclusiveStartKey) 

Source Link

Document

The primary key of the first item that this operation will evaluate.

Usage

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

License:Apache License

private <P extends ParaObject> String readPageFromTable(String appid, Pager pager, LinkedList<P> results) {
    ScanRequest scanRequest = new ScanRequest().withTableName(getTableNameForAppid(appid))
            .withLimit(pager.getLimit()).withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);

    if (!StringUtils.isBlank(pager.getLastKey())) {
        scanRequest = scanRequest.withExclusiveStartKey(
                Collections.singletonMap(Config._KEY, new AttributeValue(pager.getLastKey())));
    }/*from   ww w  .j ava2  s  .  c o  m*/

    ScanResult result = client().scan(scanRequest);
    for (Map<String, AttributeValue> item : result.getItems()) {
        P obj = fromRow(item);
        if (obj != null) {
            results.add(obj);
        }
    }

    if (result.getLastEvaluatedKey() != null) {
        return result.getLastEvaluatedKey().get(Config._KEY).getS();
    } else {
        return null;
    }
}

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From source file:com.intuit.tank.persistence.databases.AmazonDynamoDatabaseDocApi.java

License:Open Source License

/**
 * @{inheritDoc//from   w  ww  . j  a v a2 s. c o m
 */
@SuppressWarnings("unchecked")
@Override
public PagedDatabaseResult getPagedItems(String tableName, Object nextToken, String minRange, String maxRange,
        String instanceId, String jobId) {
    List<Item> ret = new ArrayList<Item>();
    Map<String, AttributeValue> lastKeyEvaluated = (Map<String, AttributeValue>) nextToken;
    ScanRequest scanRequest = new ScanRequest().withTableName(tableName);
    Map<String, Condition> conditions = new HashMap<String, Condition>();
    if (jobId != null) {
        Condition jobIdCondition = new Condition();
        jobIdCondition.withComparisonOperator(ComparisonOperator.EQ)
                .withAttributeValueList(new AttributeValue().withS(jobId));

        conditions.put(DatabaseKeys.JOB_ID_KEY.getShortKey(), jobIdCondition);
    }
    if (StringUtils.isNotBlank(instanceId)) {
        // add a filter
        Condition filter = new Condition();
        filter.withComparisonOperator(ComparisonOperator.EQ)
                .withAttributeValueList(new AttributeValue().withS(instanceId));
        scanRequest.addScanFilterEntry(DatabaseKeys.INSTANCE_ID_KEY.getShortKey(), filter);
    }
    Condition rangeKeyCondition = new Condition();
    if (minRange != null && maxRange != null) {
        rangeKeyCondition.withComparisonOperator(ComparisonOperator.BETWEEN.toString())
                .withAttributeValueList(new AttributeValue().withS(minRange))
                .withAttributeValueList(new AttributeValue().withS(maxRange));

    } else if (minRange != null) {
        rangeKeyCondition.withComparisonOperator(ComparisonOperator.GE.toString())
                .withAttributeValueList(new AttributeValue().withS(minRange));
    } else if (maxRange != null) {
        rangeKeyCondition.withComparisonOperator(ComparisonOperator.LT.toString())
                .withAttributeValueList(new AttributeValue().withS(maxRange));
    } else {
        rangeKeyCondition = null;
    }
    if (rangeKeyCondition != null) {
        conditions.put(DatabaseKeys.REQUEST_NAME_KEY.getShortKey(), rangeKeyCondition);
    }
    scanRequest.withScanFilter(conditions);
    scanRequest.withExclusiveStartKey(lastKeyEvaluated);

    ScanResult result = dynamoDb.scan(scanRequest);
    for (Map<String, AttributeValue> item : result.getItems()) {
        ret.add(getItemFromResult(item));
    }
    return new PagedDatabaseResult(ret, result.getLastEvaluatedKey());
}

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