Class GetItemRequest
- java.lang.Object
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- com.amazonaws.AmazonWebServiceRequest
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- com.amazonaws.services.dynamodbv2.model.GetItemRequest
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- All Implemented Interfaces:
ReadLimitInfo
,Serializable
,Cloneable
public class GetItemRequest extends AmazonWebServiceRequest implements Serializable, Cloneable
Represents the input of a GetItem operation.
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class com.amazonaws.AmazonWebServiceRequest
NOOP
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Constructor Summary
Constructors Constructor Description GetItemRequest()
Default constructor for GetItemRequest object.GetItemRequest(String tableName, Map<String,AttributeValue> key)
Constructs a new GetItemRequest object.GetItemRequest(String tableName, Map<String,AttributeValue> key, Boolean consistentRead)
Constructs a new GetItemRequest object.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description GetItemRequest
addExpressionAttributeNamesEntry(String key, String value)
GetItemRequest
addKeyEntry(String key, AttributeValue value)
GetItemRequest
clearExpressionAttributeNamesEntries()
Removes all the entries added into ExpressionAttributeNames.GetItemRequest
clearKeyEntries()
Removes all the entries added into Key.GetItemRequest
clone()
Creates a shallow clone of this request.boolean
equals(Object obj)
List<String>
getAttributesToGet()
Boolean
getConsistentRead()
Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.Map<String,String>
getExpressionAttributeNames()
One or more substitution tokens for attribute names in an expression.Map<String,AttributeValue>
getKey()
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.String
getProjectionExpression()
A string that identifies one or more attributes to retrieve from the table.String
getReturnConsumedCapacity()
String
getTableName()
The name of the table containing the requested item.int
hashCode()
Boolean
isConsistentRead()
Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.void
setAttributesToGet(Collection<String> attributesToGet)
void
setConsistentRead(Boolean consistentRead)
Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.void
setExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for attribute names in an expression.void
setKey(Map.Entry<String,AttributeValue> hashKey, Map.Entry<String,AttributeValue> rangeKey)
Set the hash and range key attributes of the item.void
setKey(Map<String,AttributeValue> key)
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.void
setProjectionExpression(String projectionExpression)
A string that identifies one or more attributes to retrieve from the table.void
setReturnConsumedCapacity(ReturnConsumedCapacity returnConsumedCapacity)
void
setReturnConsumedCapacity(String returnConsumedCapacity)
void
setTableName(String tableName)
The name of the table containing the requested item.String
toString()
Returns a string representation of this object; useful for testing and debugging.GetItemRequest
withAttributesToGet(String... attributesToGet)
GetItemRequest
withAttributesToGet(Collection<String> attributesToGet)
GetItemRequest
withConsistentRead(Boolean consistentRead)
Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.GetItemRequest
withExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for attribute names in an expression.GetItemRequest
withKey(Map.Entry<String,AttributeValue> hashKey, Map.Entry<String,AttributeValue> rangeKey)
Set the hash and range key attributes of the item.GetItemRequest
withKey(Map<String,AttributeValue> key)
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.GetItemRequest
withProjectionExpression(String projectionExpression)
A string that identifies one or more attributes to retrieve from the table.GetItemRequest
withReturnConsumedCapacity(ReturnConsumedCapacity returnConsumedCapacity)
GetItemRequest
withReturnConsumedCapacity(String returnConsumedCapacity)
GetItemRequest
withTableName(String tableName)
The name of the table containing the requested item.-
Methods inherited from class com.amazonaws.AmazonWebServiceRequest
copyBaseTo, getCloneRoot, getCloneSource, getCustomQueryParameters, getCustomRequestHeaders, getGeneralProgressListener, getReadLimit, getRequestClientOptions, getRequestCredentials, getRequestCredentialsProvider, getRequestMetricCollector, getSdkClientExecutionTimeout, getSdkRequestTimeout, putCustomQueryParameter, putCustomRequestHeader, setGeneralProgressListener, setRequestCredentials, setRequestCredentialsProvider, setRequestMetricCollector, setSdkClientExecutionTimeout, setSdkRequestTimeout, withGeneralProgressListener, withRequestMetricCollector, withSdkClientExecutionTimeout, withSdkRequestTimeout
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Constructor Detail
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GetItemRequest
public GetItemRequest()
Default constructor for GetItemRequest object. Callers should use the setter or fluent setter (with...) methods to initialize the object after creating it.
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GetItemRequest
public GetItemRequest(String tableName, Map<String,AttributeValue> key)
Constructs a new GetItemRequest object. Callers should use the setter or fluent setter (with...) methods to initialize any additional object members.- Parameters:
tableName
- The name of the table containing the requested item.key
- A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
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GetItemRequest
public GetItemRequest(String tableName, Map<String,AttributeValue> key, Boolean consistentRead)
Constructs a new GetItemRequest object. Callers should use the setter or fluent setter (with...) methods to initialize any additional object members.- Parameters:
tableName
- The name of the table containing the requested item.key
- A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
consistentRead
- Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.
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Method Detail
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setTableName
public void setTableName(String tableName)
The name of the table containing the requested item.
- Parameters:
tableName
- The name of the table containing the requested item.
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getTableName
public String getTableName()
The name of the table containing the requested item.
- Returns:
- The name of the table containing the requested item.
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withTableName
public GetItemRequest withTableName(String tableName)
The name of the table containing the requested item.
- Parameters:
tableName
- The name of the table containing the requested item.- Returns:
- Returns a reference to this object so that method calls can be chained together.
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getKey
public Map<String,AttributeValue> getKey()
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.
For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
- Returns:
- A map of attribute names to AttributeValue objects,
representing the primary key of the item to retrieve.
For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
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setKey
public void setKey(Map<String,AttributeValue> key)
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.
For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
- Parameters:
key
- A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
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withKey
public GetItemRequest withKey(Map<String,AttributeValue> key)
A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.
For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
- Parameters:
key
- A map of attribute names to AttributeValue objects, representing the primary key of the item to retrieve.For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
- Returns:
- Returns a reference to this object so that method calls can be chained together.
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addKeyEntry
public GetItemRequest addKeyEntry(String key, AttributeValue value)
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clearKeyEntries
public GetItemRequest clearKeyEntries()
Removes all the entries added into Key. <p> Returns a reference to this object so that method calls can be chained together.
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getAttributesToGet
public List<String> getAttributesToGet()
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
- Returns:
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
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setAttributesToGet
public void setAttributesToGet(Collection<String> attributesToGet)
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
- Parameters:
attributesToGet
-This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
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withAttributesToGet
public GetItemRequest withAttributesToGet(String... attributesToGet)
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
NOTE: This method appends the values to the existing list (if any). Use
setAttributesToGet(java.util.Collection)
orwithAttributesToGet(java.util.Collection)
if you want to override the existing values.- Parameters:
attributesToGet
-This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
- Returns:
- Returns a reference to this object so that method calls can be chained together.
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withAttributesToGet
public GetItemRequest withAttributesToGet(Collection<String> attributesToGet)
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
- Parameters:
attributesToGet
-This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
- Returns:
- Returns a reference to this object so that method calls can be chained together.
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setConsistentRead
public void setConsistentRead(Boolean consistentRead)
Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.- Parameters:
consistentRead
- Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.
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getConsistentRead
public Boolean getConsistentRead()
Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.- Returns:
- Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.
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withConsistentRead
public GetItemRequest withConsistentRead(Boolean consistentRead)
Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.- Parameters:
consistentRead
- Determines the read consistency model: If set totrue
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.- Returns:
- Returns a reference to this object so that method calls can be chained together.
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isConsistentRead
public Boolean isConsistentRead()
Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.- Returns:
- Determines the read consistency model: If set to
true
, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.
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setReturnConsumedCapacity
public void setReturnConsumedCapacity(String returnConsumedCapacity)
- Parameters:
returnConsumedCapacity
-- See Also:
ReturnConsumedCapacity
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getReturnConsumedCapacity
public String getReturnConsumedCapacity()
- Returns:
- See Also:
ReturnConsumedCapacity
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withReturnConsumedCapacity
public GetItemRequest withReturnConsumedCapacity(String returnConsumedCapacity)
- Parameters:
returnConsumedCapacity
-- Returns:
- Returns a reference to this object so that method calls can be chained together.
- See Also:
ReturnConsumedCapacity
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setReturnConsumedCapacity
public void setReturnConsumedCapacity(ReturnConsumedCapacity returnConsumedCapacity)
- Parameters:
returnConsumedCapacity
-- See Also:
ReturnConsumedCapacity
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withReturnConsumedCapacity
public GetItemRequest withReturnConsumedCapacity(ReturnConsumedCapacity returnConsumedCapacity)
- Parameters:
returnConsumedCapacity
-- Returns:
- Returns a reference to this object so that method calls can be chained together.
- See Also:
ReturnConsumedCapacity
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setProjectionExpression
public void setProjectionExpression(String projectionExpression)
A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
- Parameters:
projectionExpression
- A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
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getProjectionExpression
public String getProjectionExpression()
A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
- Returns:
- A string that identifies one or more attributes to retrieve from
the table. These attributes can include scalars, sets, or
elements of a JSON document. The attributes in the expression
must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
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withProjectionExpression
public GetItemRequest withProjectionExpression(String projectionExpression)
A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
- Parameters:
projectionExpression
- A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
ProjectionExpression replaces the legacy AttributesToGet parameter.
- Returns:
- Returns a reference to this object so that method calls can be chained together.
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getExpressionAttributeNames
public Map<String,String> getExpressionAttributeNames()
One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:
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To access an attribute whose name conflicts with a DynamoDB reserved word.
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To create a placeholder for repeating occurrences of an attribute name in an expression.
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To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
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Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
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{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
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#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
- Returns:
- One or more substitution tokens for attribute names in an
expression. The following are some use cases for using
ExpressionAttributeNames:
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To access an attribute whose name conflicts with a DynamoDB reserved word.
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To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
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Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
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{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
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#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
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setExpressionAttributeNames
public void setExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:
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To access an attribute whose name conflicts with a DynamoDB reserved word.
-
To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
-
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
-
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
-
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
- Parameters:
expressionAttributeNames
- One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:-
To access an attribute whose name conflicts with a DynamoDB reserved word.
-
To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
-
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
-
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
-
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
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withExpressionAttributeNames
public GetItemRequest withExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:
-
To access an attribute whose name conflicts with a DynamoDB reserved word.
-
To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
-
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
-
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
-
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
- Parameters:
expressionAttributeNames
- One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:-
To access an attribute whose name conflicts with a DynamoDB reserved word.
-
To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
-
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
-
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
-
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
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- Returns:
- Returns a reference to this object so that method calls can be chained together.
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addExpressionAttributeNamesEntry
public GetItemRequest addExpressionAttributeNamesEntry(String key, String value)
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clearExpressionAttributeNamesEntries
public GetItemRequest clearExpressionAttributeNamesEntries()
Removes all the entries added into ExpressionAttributeNames. <p> Returns a reference to this object so that method calls can be chained together.
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setKey
public void setKey(Map.Entry<String,AttributeValue> hashKey, Map.Entry<String,AttributeValue> rangeKey) throws IllegalArgumentException
Set the hash and range key attributes of the item.For a hash-only table, you only need to provide the hash attribute. For a hash-and-range table, you must provide both.
- Parameters:
hashKey
- a map entry including the name and value of the primary hash key.rangeKey
- a map entry including the name and value of the primary range key, or null if it is a hash-only table.- Throws:
IllegalArgumentException
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withKey
public GetItemRequest withKey(Map.Entry<String,AttributeValue> hashKey, Map.Entry<String,AttributeValue> rangeKey) throws IllegalArgumentException
Set the hash and range key attributes of the item.For a hash-only table, you only need to provide the hash attribute. For a hash-and-range table, you must provide both.
Returns a reference to this object so that method calls can be chained together.
- Parameters:
hashKey
- a map entry including the name and value of the primary hash key.rangeKey
- a map entry including the name and value of the primary range key, or null if it is a hash-only table.- Throws:
IllegalArgumentException
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toString
public String toString()
Returns a string representation of this object; useful for testing and debugging.- Overrides:
toString
in classObject
- Returns:
- A string representation of this object.
- See Also:
Object.toString()
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clone
public GetItemRequest clone()
Description copied from class:AmazonWebServiceRequest
Creates a shallow clone of this request. Explicitly does not clone the deep structure of the request object.- Overrides:
clone
in classAmazonWebServiceRequest
- See Also:
Object.clone()
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