Example usage for com.amazonaws.services.dynamodbv2.model UpdateItemRequest setConditionExpression

Introduction

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

Prototype

public void setConditionExpression(String conditionExpression) 

Source Link

Document

A condition that must be satisfied in order for a conditional update to succeed.

Usage

From source file:org.iternine.jeppetto.dao.dynamodb.DynamoDBQueryModelDAO.java

License:Apache License

private T updateItem(Map<String, AttributeValue> key, UpdateExpressionBuilder updateExpressionBuilder,
        ConditionExpressionBuilder conditionExpressionBuilder, ResultFromUpdate resultFromUpdate) {
    try {//from ww  w  .ja va  2  s.  c  om
        UpdateItemRequest updateItemRequest = new UpdateItemRequest().withTableName(tableName).withKey(key)
                .withUpdateExpression(updateExpressionBuilder.getExpression());

        Map<String, AttributeValue> expressionAttributeValues;
        Map<String, String> expressionAttributeNames;

        if (conditionExpressionBuilder == null) {
            expressionAttributeValues = updateExpressionBuilder.getExpressionAttributeValues();
            expressionAttributeNames = updateExpressionBuilder.getExpressionAttributeNames();
        } else {
            expressionAttributeValues = new LinkedHashMap<String, AttributeValue>();
            expressionAttributeNames = new LinkedHashMap<String, String>();

            expressionAttributeValues.putAll(updateExpressionBuilder.getExpressionAttributeValues());
            expressionAttributeNames.putAll(updateExpressionBuilder.getExpressionAttributeNames());

            expressionAttributeValues.putAll(conditionExpressionBuilder.getExpressionAttributeValues());
            expressionAttributeNames.putAll(conditionExpressionBuilder.getExpressionAttributeNames());

            updateItemRequest.setConditionExpression(conditionExpressionBuilder.getExpression());
        }

        if (!expressionAttributeValues.isEmpty()) {
            updateItemRequest.setExpressionAttributeValues(expressionAttributeValues);
        }

        if (!expressionAttributeNames.isEmpty()) {
            updateItemRequest.setExpressionAttributeNames(expressionAttributeNames);
        }

        if (resultFromUpdate != ResultFromUpdate.ReturnNone) {
            updateItemRequest
                    .setReturnValues(resultFromUpdate == ResultFromUpdate.ReturnPreUpdate ? ReturnValue.ALL_OLD
                            : ReturnValue.ALL_NEW);

            UpdateItemResult result = dynamoDB.updateItem(updateItemRequest);

            T t = ConversionUtil.getObjectFromItem(result.getAttributes(), entityClass);

            ((DynamoDBPersistable) t).__markPersisted(dynamoDB.toString());

            return t;
        } else {
            dynamoDB.updateItem(updateItemRequest);

            return null;
        }
    } catch (Exception e) {
        throw new JeppettoException(e);
    }
}

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