com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper

Class DynamoDBScanExpression

java.lang.Object

com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBScanExpression

public class DynamoDBScanExpression
extends Object

Options for filtering results from a scan operation. For example, callers can specify filter conditions so that only objects whose attributes match different conditions are returned (see ComparisonOperator for more information on the available comparison types).

See Also:

DynamoDBMapper.scan(Class, DynamoDBScanExpression)

Constructor Summary

Constructors

Constructor and Description
DynamoDBScanExpression()

Method Summary

Methods

Modifier and Type	Method and Description
DynamoDBScanExpression	addExpressionAttributeNamesEntry(String key, String value) One or more substitution variables for simplifying complex expressions.
DynamoDBScanExpression	addExpressionAttributeValuesEntry(String key, AttributeValue value) One or more values that can be substituted in an expression.
void	addFilterCondition(String attributeName, Condition condition) Adds a new filter condition to the current scan filter.
DynamoDBScanExpression	clearExpressionAttributeNamesEntries() Removes all the entries added into ExpressionAttributeNames.
DynamoDBScanExpression	clearExpressionAttributeValuesEntries() Removes all the entries added into ExpressionAttributeValues.
String	getConditionalOperator() Returns the logical operator on the filter conditions of this scan.
Map<String,AttributeValue>	getExclusiveStartKey() Returns the exclusive start key for this scan.
Map<String,String>	getExpressionAttributeNames() One or more substitution variables for simplifying complex expressions.
Map<String,AttributeValue>	getExpressionAttributeValues() One or more values that can be substituted in an expression.
String	getFilterExpression() Evaluates the query results and returns only the desired values.
Integer	getLimit() Returns the limit of items to scan during this scan.
Map<String,Condition>	getScanFilter() Returns the scan filter as a map of attribute names to conditions.
Integer	getSegment() Returns the ID of the segment to be scanned.
Integer	getTotalSegments() Returns the total number of segments into which the scan will be divided.
void	setConditionalOperator(ConditionalOperator conditionalOperator) Sets the logical operator on the filter conditions of this scan.
void	setConditionalOperator(String conditionalOperator) Sets the logical operator on the filter conditions of this scan.
void	setExclusiveStartKey(Map<String,AttributeValue> exclusiveStartKey) Sets the exclusive start key for this scan.
void	setExpressionAttributeNames(Map<String,String> expressionAttributeNames) One or more substitution variables for simplifying complex expressions.
void	setExpressionAttributeValues(Map<String,AttributeValue> expressionAttributeValues) One or more values that can be substituted in an expression.
void	setFilterExpression(String filterExpression) Evaluates the query results and returns only the desired values.
void	setLimit(Integer limit) Sets the limit of items to scan during this scan.
void	setScanFilter(Map<String,Condition> scanFilter) Sets the scan filter to the map of attribute names to conditions given.
void	setSegment(Integer segment) Sets the ID of the segment to be scanned.
void	setTotalSegments(Integer totalSegments) Sets the total number of segments into which the scan will be divided.
DynamoDBScanExpression	withConditionalOperator(ConditionalOperator conditionalOperator) Sets the logical operator on the filter conditions of this scan and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withConditionalOperator(String conditionalOperator) Sets the logical operator on the filter conditions of this scan and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withExclusiveStartKey(Map<String,AttributeValue> exclusiveStartKey) Sets the exclusive start key for this scan and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withExpressionAttributeNames(Map<String,String> expressionAttributeNames) One or more substitution variables for simplifying complex expressions.
DynamoDBScanExpression	withExpressionAttributeValues(Map<String,AttributeValue> expressionAttributeValues) One or more values that can be substituted in an expression.
DynamoDBScanExpression	withFilterConditionEntry(String attributeName, Condition condition) Adds a new filter condition to the current scan filter and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withFilterExpression(String filterExpression) Evaluates the query results and returns only the desired values.
DynamoDBScanExpression	withLimit(Integer limit) Sets the limit of items to scan and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withScanFilter(Map<String,Condition> scanFilter) Sets the scan filter to the map of attribute names to conditions given and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withSegment(Integer segment) Sets the ID of the segment to be scanned and returns a pointer to this object for method-chaining.
DynamoDBScanExpression	withTotalSegments(Integer totalSegments) Sets the total number of segments into which the scan will be divided and returns a pointer to this object for method-chaining.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DynamoDBScanExpression

public DynamoDBScanExpression()

Method Detail

getScanFilter

public Map<String,Condition> getScanFilter()

Returns the scan filter as a map of attribute names to conditions.

Returns:

The scan filter as a map of attribute names to conditions.

setScanFilter

public void setScanFilter(Map<String,Condition> scanFilter)

Sets the scan filter to the map of attribute names to conditions given.

Parameters:

scanFilter - The map of attribute names to conditions to use when filtering scan results.

withScanFilter

public DynamoDBScanExpression withScanFilter(Map<String,Condition> scanFilter)

Sets the scan filter to the map of attribute names to conditions given and returns a pointer to this object for method-chaining.

Parameters:

scanFilter - The map of attribute names to conditions to use when filtering scan results.

addFilterCondition

public void addFilterCondition(String attributeName,
                      Condition condition)

Adds a new filter condition to the current scan filter.

Parameters:

attributeName - The name of the attribute on which the specified condition operates.

condition - The condition which describes how the specified attribute is compared and if a row of data is included in the results returned by the scan operation.

withFilterConditionEntry

public DynamoDBScanExpression withFilterConditionEntry(String attributeName,
                                              Condition condition)

Adds a new filter condition to the current scan filter and returns a pointer to this object for method-chaining.

Parameters:

attributeName - The name of the attribute on which the specified condition operates.

condition - The condition which describes how the specified attribute is compared and if a row of data is included in the results returned by the scan operation.

getExclusiveStartKey

public Map<String,AttributeValue> getExclusiveStartKey()

Returns the exclusive start key for this scan.

setExclusiveStartKey

public void setExclusiveStartKey(Map<String,AttributeValue> exclusiveStartKey)

Sets the exclusive start key for this scan.

withExclusiveStartKey

public DynamoDBScanExpression withExclusiveStartKey(Map<String,AttributeValue> exclusiveStartKey)

Sets the exclusive start key for this scan and returns a pointer to this object for method-chaining.

getLimit

public Integer getLimit()

Returns the limit of items to scan during this scan.

Use with caution. Please note that this is not the same as the number of items to return from the scan operation -- the operation will cease and return as soon as this many items are scanned, even if no matching results are found. Furthermore, PaginatedScanList will execute as many scan operations as necessary until it either reaches the end of the result set as indicated by DynamoDB or enough elements are available to fulfill the list operation (e.g. iteration). Therefore, except when scanning without a scan filter, it's usually bad practice to set a low limit, since doing so will often generate the same amount of traffic to DynamoDB but with a greater number of round trips and therefore more overall latency.

setLimit

public void setLimit(Integer limit)

Sets the limit of items to scan during this scan. Please note that this is not the same as the number of items to return from the scan operation -- the operation will cease and return as soon as this many items are scanned, even if no matching results are found.

See Also:

getLimit()

withLimit

public DynamoDBScanExpression withLimit(Integer limit)

Sets the limit of items to scan and returns a pointer to this object for method-chaining. Please note that this is not the same as the number of items to return from the scan operation -- the operation will cease and return as soon as this many items are scanned, even if no matching results are found.

See Also:

getLimit()

getTotalSegments

public Integer getTotalSegments()

Returns the total number of segments into which the scan will be divided.

setTotalSegments

public void setTotalSegments(Integer totalSegments)

Sets the total number of segments into which the scan will be divided.

withTotalSegments

public DynamoDBScanExpression withTotalSegments(Integer totalSegments)

Sets the total number of segments into which the scan will be divided and returns a pointer to this object for method-chaining.

getSegment

public Integer getSegment()

Returns the ID of the segment to be scanned.

setSegment

public void setSegment(Integer segment)

Sets the ID of the segment to be scanned.

withSegment

public DynamoDBScanExpression withSegment(Integer segment)

Sets the ID of the segment to be scanned and returns a pointer to this object for method-chaining.

getConditionalOperator

public String getConditionalOperator()

Returns the logical operator on the filter conditions of this scan.

setConditionalOperator

public void setConditionalOperator(String conditionalOperator)

Sets the logical operator on the filter conditions of this scan.

withConditionalOperator

public DynamoDBScanExpression withConditionalOperator(String conditionalOperator)

Sets the logical operator on the filter conditions of this scan and returns a pointer to this object for method-chaining.

setConditionalOperator

public void setConditionalOperator(ConditionalOperator conditionalOperator)

Sets the logical operator on the filter conditions of this scan.

withConditionalOperator

public DynamoDBScanExpression withConditionalOperator(ConditionalOperator conditionalOperator)

Sets the logical operator on the filter conditions of this scan and returns a pointer to this object for method-chaining.

getFilterExpression

public String getFilterExpression()

Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

Returns:

Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

See Also:

ScanRequest.getFilterExpression()

setFilterExpression

public void setFilterExpression(String filterExpression)

Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

Parameters:

filterExpression - Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

See Also:

ScanRequest.setFilterExpression(String)

withFilterExpression

public DynamoDBScanExpression withFilterExpression(String filterExpression)

Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

Returns a reference to this object so that method calls can be chained together.

Parameters:

filterExpression - Evaluates the query results and returns only the desired values.

The condition you specify is applied to the items queried; any items that do not match the expression are not returned.

Returns:

A reference to this updated object so that method calls can be chained together.

See Also:

ScanRequest.withFilterExpression(String)

getExpressionAttributeNames

public Map<String,String> getExpressionAttributeNames()

One or more substitution variables for simplifying complex expressions.

Returns:

One or more substitution variables for simplifying complex expressions.

See Also:

scanRequest#getExpressionAttributeNames()

setExpressionAttributeNames

public void setExpressionAttributeNames(Map<String,String> expressionAttributeNames)

One or more substitution variables for simplifying complex expressions.

Parameters:

expressionAttributeNames - One or more substitution variables for simplifying complex expressions.

See Also:

ScanRequest.setExpressionAttributeNames(Map)

withExpressionAttributeNames

public DynamoDBScanExpression withExpressionAttributeNames(Map<String,String> expressionAttributeNames)

One or more substitution variables for simplifying complex expressions.

Parameters:

expressionAttributeNames - One or more substitution variables for simplifying complex expressions.

Returns:

A reference to this updated object so that method calls can be chained together.

See Also:

ScanRequest.withExpressionAttributeNames(Map)

addExpressionAttributeNamesEntry

public DynamoDBScanExpression addExpressionAttributeNamesEntry(String key,
                                                      String value)

One or more substitution variables for simplifying complex expressions. The method adds a new key-value pair into ExpressionAttributeNames parameter, and returns a reference to this object so that method calls can be chained together.

Parameters:

key - The key of the entry to be added into ExpressionAttributeNames.

value - The corresponding value of the entry to be added into ExpressionAttributeNames.

See Also:

ScanRequest.addExpressionAttributeNamesEntry(String, String)

clearExpressionAttributeNamesEntries

public DynamoDBScanExpression clearExpressionAttributeNamesEntries()

Removes all the entries added into ExpressionAttributeNames.

Returns a reference to this object so that method calls can be chained together.

getExpressionAttributeValues

public Map<String,AttributeValue> getExpressionAttributeValues()

One or more values that can be substituted in an expression.

Returns:

One or more values that can be substituted in an expression.

See Also:

ScanRequest.getExpressionAttributeValues()

setExpressionAttributeValues

public void setExpressionAttributeValues(Map<String,AttributeValue> expressionAttributeValues)

One or more values that can be substituted in an expression.

Parameters:

expressionAttributeValues - One or more values that can be substituted in an expression.

See Also:

ScanRequest.setExpressionAttributeValues(Map)

withExpressionAttributeValues

public DynamoDBScanExpression withExpressionAttributeValues(Map<String,AttributeValue> expressionAttributeValues)

One or more values that can be substituted in an expression.

Parameters:

expressionAttributeValues - One or more values that can be substituted in an expression.

Returns:

A reference to this updated object so that method calls can be chained together.

See Also:

ScanRequest.withExpressionAttributeValues(Map)

addExpressionAttributeValuesEntry

public DynamoDBScanExpression addExpressionAttributeValuesEntry(String key,
                                                       AttributeValue value)

One or more values that can be substituted in an expression. The method adds a new key-value pair into ExpressionAttributeValues parameter, and returns a reference to this object so that method calls can be chained together.

Parameters:

key - The key of the entry to be added into ExpressionAttributeValues.

value - The corresponding value of the entry to be added into ExpressionAttributeValues.

See Also:

ScanRequest.addExpressionAttributeValuesEntry(String, AttributeValue)

clearExpressionAttributeValuesEntries

public DynamoDBScanExpression clearExpressionAttributeValuesEntries()

Removes all the entries added into ExpressionAttributeValues.

Returns a reference to this object so that method calls can be chained together.