com.amazonaws.services.dynamodbv2.model
Class ExpectedAttributeValue

java.lang.Object
  com.amazonaws.services.dynamodbv2.model.ExpectedAttributeValue

All Implemented Interfaces:

Serializable

public class ExpectedAttributeValue
extends Object
implements Serializable

An attribute value used with conditional DeleteItem , PutItem or UpdateItem operations. Amazon DynamoDB will check to see if the attribute value already exists; or if the attribute exists and has a particular value before updating it.

See Also:

Serialized Form

Constructor Summary

ExpectedAttributeValue()
Default constructor for a new ExpectedAttributeValue object.

ExpectedAttributeValue(AttributeValue value)
Constructs a new ExpectedAttributeValue object.

ExpectedAttributeValue(Boolean exists)
Constructs a new ExpectedAttributeValue object.

Method Summary

boolean	equals(Object obj)
Boolean	getExists() Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:
AttributeValue	getValue() Represents the data for an attribute.
int	hashCode()
Boolean	isExists() Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:
void	setExists(Boolean exists) Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:
void	setValue(AttributeValue value) Represents the data for an attribute.
String	toString() Returns a string representation of this object; useful for testing and debugging.
ExpectedAttributeValue	withExists(Boolean exists) Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:
ExpectedAttributeValue	withValue(AttributeValue value) Represents the data for an attribute.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ExpectedAttributeValue

public ExpectedAttributeValue()

Default constructor for a new ExpectedAttributeValue object. Callers should use the setter or fluent setter (with...) methods to initialize this object after creating it.

ExpectedAttributeValue

public ExpectedAttributeValue(AttributeValue value)

Constructs a new ExpectedAttributeValue object. Callers should use the setter or fluent setter (with...) methods to initialize any additional object members.

Parameters:

value - Represents the data for an attribute. You can set one, and only one, of the elements.

ExpectedAttributeValue

public ExpectedAttributeValue(Boolean exists)

Constructs a new ExpectedAttributeValue object. Callers should use the setter or fluent setter (with...) methods to initialize any additional object members.

Parameters:

exists - Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

Method Detail

getValue

public AttributeValue getValue()

Represents the data for an attribute. You can set one, and only one, of the elements.

Returns:

Represents the data for an attribute. You can set one, and only one, of the elements.

setValue

public void setValue(AttributeValue value)

Represents the data for an attribute. You can set one, and only one, of the elements.

Parameters:

value - Represents the data for an attribute. You can set one, and only one, of the elements.

withValue

public ExpectedAttributeValue withValue(AttributeValue value)

Represents the data for an attribute. You can set one, and only one, of the elements.

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

Parameters:

value - Represents the data for an attribute. You can set one, and only one, of the elements.

isExists

public Boolean isExists()

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

Returns:

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

setExists

public void setExists(Boolean exists)

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

Parameters:

exists - Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

withExists

public ExpectedAttributeValue withExists(Boolean exists)

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

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

Parameters:

exists - Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

getExists

public Boolean getExists()

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

Returns:

Causes Amazon DynamoDB to evaluate the value before attempting a conditional operation:

• If Exists is true, Amazon DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

• If Exists is false, Amazon DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

The default setting for Exists is true. If you supply a Value all by itself, Amazon DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

Amazon DynamoDB returns a ValidationException if:

• Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

• Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

toString

public String toString()

Returns a string representation of this object; useful for testing and debugging.

Overrides:

toString in class Object

Returns:

A string representation of this object.

See Also:

Object.toString()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object