public class KeysAndAttributes extends Object implements Serializable
Represents a set of primary keys and, for each key, the attributes to retrieve from the table.
For each primary key, you must provide all of the key attributes. For example, with a hash type primary key, you only need to specify the hash attribute. For a hash-and-range type primary key, you must specify both the hash attribute and the range attribute.
Constructor and Description |
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KeysAndAttributes() |
Modifier and Type | Method and Description |
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KeysAndAttributes |
addExpressionAttributeNamesEntry(String key,
String value)
One or more substitution tokens for simplifying complex expressions.
|
KeysAndAttributes |
clearExpressionAttributeNamesEntries()
Removes all the entries added into ExpressionAttributeNames.
|
boolean |
equals(Object obj) |
List<String> |
getAttributesToGet()
One or more attributes to retrieve from the table or index.
|
Boolean |
getConsistentRead()
The consistency of a read operation.
|
Map<String,String> |
getExpressionAttributeNames()
One or more substitution tokens for simplifying complex expressions.
|
List<Map<String,AttributeValue>> |
getKeys()
The primary key attribute values that define the items and the
attributes associated with the items.
|
String |
getProjectionExpression()
One or more attributes to retrieve from the table.
|
int |
hashCode() |
Boolean |
isConsistentRead()
The consistency of a read operation.
|
void |
setAttributesToGet(Collection<String> attributesToGet)
One or more attributes to retrieve from the table or index.
|
void |
setConsistentRead(Boolean consistentRead)
The consistency of a read operation.
|
void |
setExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for simplifying complex expressions.
|
void |
setKeys(Collection<Map<String,AttributeValue>> keys)
The primary key attribute values that define the items and the
attributes associated with the items.
|
void |
setProjectionExpression(String projectionExpression)
One or more attributes to retrieve from the table.
|
String |
toString()
Returns a string representation of this object; useful for testing and
debugging.
|
KeysAndAttributes |
withAttributesToGet(Collection<String> attributesToGet)
One or more attributes to retrieve from the table or index.
|
KeysAndAttributes |
withAttributesToGet(String... attributesToGet)
One or more attributes to retrieve from the table or index.
|
KeysAndAttributes |
withConsistentRead(Boolean consistentRead)
The consistency of a read operation.
|
KeysAndAttributes |
withExpressionAttributeNames(Map<String,String> expressionAttributeNames)
One or more substitution tokens for simplifying complex expressions.
|
KeysAndAttributes |
withKeys(Collection<Map<String,AttributeValue>> keys)
The primary key attribute values that define the items and the
attributes associated with the items.
|
KeysAndAttributes |
withKeys(Map<String,AttributeValue>... keys)
The primary key attribute values that define the items and the
attributes associated with the items.
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KeysAndAttributes |
withProjectionExpression(String projectionExpression)
One or more attributes to retrieve from the table.
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public List<Map<String,AttributeValue>> getKeys()
Constraints:
Length: 1 - 100
public void setKeys(Collection<Map<String,AttributeValue>> keys)
Constraints:
Length: 1 - 100
keys
- The primary key attribute values that define the items and the
attributes associated with the items.public KeysAndAttributes withKeys(Map<String,AttributeValue>... keys)
Returns a reference to this object so that method calls can be chained together.
Constraints:
Length: 1 - 100
keys
- The primary key attribute values that define the items and the
attributes associated with the items.public KeysAndAttributes withKeys(Collection<Map<String,AttributeValue>> keys)
Returns a reference to this object so that method calls can be chained together.
Constraints:
Length: 1 - 100
keys
- The primary key attribute values that define the items and the
attributes associated with the items.public List<String> getAttributesToGet()
Constraints:
Length: 1 -
public void setAttributesToGet(Collection<String> attributesToGet)
Constraints:
Length: 1 -
attributesToGet
- One or more attributes to retrieve from the table or index. If no
attribute names are specified then all attributes will be returned. If
any of the specified attributes are not found, they will not appear in
the result.public KeysAndAttributes withAttributesToGet(String... attributesToGet)
Returns a reference to this object so that method calls can be chained together.
Constraints:
Length: 1 -
attributesToGet
- One or more attributes to retrieve from the table or index. If no
attribute names are specified then all attributes will be returned. If
any of the specified attributes are not found, they will not appear in
the result.public KeysAndAttributes withAttributesToGet(Collection<String> attributesToGet)
Returns a reference to this object so that method calls can be chained together.
Constraints:
Length: 1 -
attributesToGet
- One or more attributes to retrieve from the table or index. If no
attribute names are specified then all attributes will be returned. If
any of the specified attributes are not found, they will not appear in
the result.public Boolean isConsistentRead()
true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.public void setConsistentRead(Boolean consistentRead)
true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.consistentRead
- The consistency of a read operation. If set to true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.public KeysAndAttributes withConsistentRead(Boolean consistentRead)
true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.
Returns a reference to this object so that method calls can be chained together.
consistentRead
- The consistency of a read operation. If set to true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.public Boolean getConsistentRead()
true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.true
, then
a strongly consistent read is used; otherwise, an eventually
consistent read is used.public String getProjectionExpression()
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.
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.
public void setProjectionExpression(String projectionExpression)
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.
projectionExpression
- 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.
public KeysAndAttributes withProjectionExpression(String projectionExpression)
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.
Returns a reference to this object so that method calls can be chained together.
projectionExpression
- 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.
public Map<String,String> getExpressionAttributeNames()
To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
public void setExpressionAttributeNames(Map<String,String> expressionAttributeNames)
To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
expressionAttributeNames
- One or more substitution tokens for simplifying complex expressions.
The following are some use cases for an
ExpressionAttributeNames value: To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
public KeysAndAttributes withExpressionAttributeNames(Map<String,String> expressionAttributeNames)
To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
Returns a reference to this object so that method calls can be chained together.
expressionAttributeNames
- One or more substitution tokens for simplifying complex expressions.
The following are some use cases for an
ExpressionAttributeNames value: To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
public KeysAndAttributes addExpressionAttributeNamesEntry(String key, String value)
To shorten an attribute name that is very long or unwieldy in an expression.
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 expression:
order.customerInfo.LastName = "Smith" OR
order.customerInfo.LastName = "Jones"
Now suppose that you specified the following for ExpressionAttributeNames:
{"n":"order.customerInfo.LastName"}
The expression can now be simplified as follows:
#n = "Smith" OR #n = "Jones"
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.
key
- The key of the entry to be added into ExpressionAttributeNames.value
- The corresponding value of the entry to be added into ExpressionAttributeNames.public KeysAndAttributes clearExpressionAttributeNamesEntries()
Returns a reference to this object so that method calls can be chained together.
public String toString()
toString
in class Object
Object.toString()
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