Example usage for com.amazonaws.services.dynamodbv2.document.spec ScanSpec withValueMap

Introduction

In this page you can find the example usage for com.amazonaws.services.dynamodbv2.document.spec ScanSpec withValueMap.

Prototype

public ScanSpec withValueMap(Map<String, Object> valueMap) 

Source Link

Document

Applicable only when an expression has been specified.

Usage

From source file:com.clicktravel.infrastructure.persistence.aws.dynamodb.DynamoDocumentStoreTemplate.java

License:Apache License

private <T extends Item> ScanSpec generateScanSpec(final AttributeQuery query, final Class<T> tableItemType)
        throws InstantiationException, IllegalAccessException, IllegalArgumentException,
        InvocationTargetException, NoSuchMethodException, SecurityException {
    final Class<?> clazz = getScanSpecOperandType(query.getAttributeName(), tableItemType);

    ScanSpec scanSpec = new ScanSpec();

    final StringBuilder filterExpression = new StringBuilder();
    final ValueMap valueMap = new ValueMap();
    int valueMapCount = 0;

    if (query.getCondition().getComparisonOperator() == Operators.NULL) {
        filterExpression.append("attribute_not_exists(").append(query.getAttributeName()).append(")");
    } else if (query.getCondition().getComparisonOperator() == Operators.NOT_NULL) {
        filterExpression.append("attribute_exists(").append(query.getAttributeName()).append(")");
    } else {//w  ww . j a v  a2 s.c  o m
        if (query.getCondition().getComparisonOperator() == Operators.EQUALS) {
            filterExpression.append(query.getAttributeName()).append(" IN (");

            final Iterator<String> valueIterator = query.getCondition().getValues().iterator();
            while (valueIterator.hasNext()) {
                filterExpression.append(":").append(valueMapCount);
                valueMap.with(":" + valueMapCount, valueIterator.next());
                valueMapCount++;
                if (valueIterator.hasNext()) {
                    filterExpression.append(",");
                }
            }
            filterExpression.append(")");
        } else if (query.getCondition().getComparisonOperator() == Operators.LESS_THAN_OR_EQUALS) {
            if (query.getCondition().getValues().size() == 1) {
                filterExpression.append(query.getAttributeName()).append(" <= ").append(":")
                        .append(valueMapCount);
                final Object valueInstance = clazz.getConstructor(String.class)
                        .newInstance(query.getCondition().getValues().iterator().next());
                valueMap.with(":" + valueMapCount, valueInstance);
                valueMapCount++;
            } else {
                // throw exeption??
            }
        } else if (query.getCondition().getComparisonOperator() == Operators.GREATER_THAN_OR_EQUALS) {
            if (query.getCondition().getValues().size() == 1) {
                filterExpression.append(query.getAttributeName()).append(" >= ").append(":")
                        .append(valueMapCount);
                final Object valueInstance = clazz.getConstructor(String.class)
                        .newInstance(query.getCondition().getValues().iterator().next());
                valueMap.with(":" + valueMapCount, valueInstance);
                valueMapCount++;
            } else {
                // throw exeption??
            }
        }
    }

    if (filterExpression.length() > 0) {
        scanSpec = scanSpec.withFilterExpression(filterExpression.toString());
    }
    if (valueMap.size() > 0) {
        scanSpec = scanSpec.withValueMap(valueMap);
    }
    return scanSpec;
}

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