本文整理汇总了Java中com.amazonaws.services.dynamodbv2.model.UpdateItemRequest.getUpdateExpression方法的典型用法代码示例。如果您正苦于以下问题：Java UpdateItemRequest.getUpdateExpression方法的具体用法？Java UpdateItemRequest.getUpdateExpression怎么用？Java UpdateItemRequest.getUpdateExpression使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类com.amazonaws.services.dynamodbv2.model.UpdateItemRequest的用法示例。
在下文中一共展示了UpdateItemRequest.getUpdateExpression方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: updateItem
import com.amazonaws.services.dynamodbv2.model.UpdateItemRequest; //导入方法依赖的package包/类
UpdateItemResult updateItem(final UpdateItemRequest request) throws BackendException {
setUserAgent(request);
UpdateItemResult result;
final int bytes;
if (request.getUpdateExpression() != null) {
bytes = calculateExpressionBasedUpdateSize(request);
} else {
bytes = calculateItemUpdateSizeInBytes(request.getAttributeUpdates());
}
getBytesHistogram(UPDATE_ITEM, request.getTableName()).update(bytes);
final int wcu = computeWcu(bytes);
timedWriteThrottle(UPDATE_ITEM, request.getTableName(), wcu);
final Timer.Context apiTimerContext = getTimerContext(UPDATE_ITEM, request.getTableName());
try {
result = client.updateItem(request);
} catch (Exception e) {
throw processDynamoDbApiException(e, UPDATE_ITEM, request.getTableName());
} finally {
apiTimerContext.stop();
}
meterConsumedCapacity(UPDATE_ITEM, result.getConsumedCapacity());
return result;
}
示例2: calculateExpressionBasedUpdateSize
import com.amazonaws.services.dynamodbv2.model.UpdateItemRequest; //导入方法依赖的package包/类
/**
* This method calculates a lower bound of the size of a new item created with UpdateItem UpdateExpression. It does not
* account for the size of the attribute names of the document paths in the attribute names map and it assumes that the
* UpdateExpression only uses the SET action to assign to top-level attributes.
* @param request UpdateItem request that uses update expressions
* @return the size of the post-update image of the item
*/
private int calculateExpressionBasedUpdateSize(final UpdateItemRequest request) {
if (request == null || request.getUpdateExpression() == null) {
throw new IllegalArgumentException("request did not use update expression");
}
int size = calculateItemSizeInBytes(request.getKey());
for (AttributeValue value : request.getExpressionAttributeValues().values()) {
size += calculateAttributeSizeInBytes(value);
}
return size;
}