All Known Implementing Classes:

GraphqlBooleanCoercing, GraphqlFloatCoercing, GraphqlIDCoercing, GraphqlIntCoercing, GraphqlStringCoercing
```
@PublicSpi
public interface Coercing<I,O>
```
The Coercing interface is used by GraphQLScalarTypes to parse and serialize object values.
There are two major responsibilities, result coercion and input coercion.
Result coercion is taking a value from a Java object and coercing it into the constraints of the scalar type. For example imagine a DateTime scalar, the result coercion would need to take an object and turn it into a ISO date or throw an exception if it cant.
Input coercion is made out of three different methods parseLiteral(Object) which converts an literal Ast into an internal input value, parseValue(Object) which converts an external input value into an internal one and valueToLiteral(Object) which is a translation between an external input value into a literal.
The relationship between these three methods is as follows: It is required that every valid external input values for parseValue(Object) is also valid for valueToLiteral(Object) and vice versa. Furthermore the literals returned by valueToLiteral(Object) are required to be valid for parseLiteral(Object).

Method Summary

All Methods Instance Methods Default Methods Deprecated Methods
Modifier and Type	Method	Description
`default @Nullable I`	`parseLiteral(@NonNull Value<?> input, @NonNull CoercedVariables variables, @NonNull GraphQLContext graphQLContext, @NonNull java.util.Locale locale)`	Called during query execution to convert a query input AST node into a Java object acceptable for the scalar type.
`default @Nullable I`	`parseLiteral(@NonNull java.lang.Object input)`	Deprecated.
`default @Nullable I`	`parseLiteral(java.lang.Object input, java.util.Map<java.lang.String,java.lang.Object> variables)`	Deprecated.
`default @Nullable I`	`parseValue(@NonNull java.lang.Object input)`	Deprecated.
`default @Nullable I`	`parseValue(@NonNull java.lang.Object input, @NonNull GraphQLContext graphQLContext, @NonNull java.util.Locale locale)`	Called to resolve an input from a query variable into a Java object acceptable for the scalar type.
`default @Nullable O`	`serialize(@NonNull java.lang.Object dataFetcherResult)`	Deprecated.
`default @Nullable O`	`serialize(@NonNull java.lang.Object dataFetcherResult, @NonNull GraphQLContext graphQLContext, @NonNull java.util.Locale locale)`	Called to convert a Java object result of a DataFetcher to a valid runtime value for the scalar type.
`default @NonNull Value`	`valueToLiteral(@NonNull java.lang.Object input)`	Deprecated.
`default @NonNull Value<?>`	`valueToLiteral(@NonNull java.lang.Object input, @NonNull GraphQLContext graphQLContext, @NonNull java.util.Locale locale)`	Converts an external input value to a literal (Ast Value).

- Method Detail
  - serialize
```
@Deprecated(since="2022-08-22")
default @Nullable O serialize(@NonNull java.lang.Object dataFetcherResult)
                       throws CoercingSerializeException
```
    Deprecated.
    
    This is deprecated and you should implement serialize(Object, GraphQLContext, Locale) instead
    Called to convert a Java object result of a DataFetcher to a valid runtime value for the scalar type.
    Note : Throw CoercingSerializeException if there is fundamental problem during serialization, don't return null to indicate failure.
    Note : You should not allow RuntimeExceptions to come out of your serialize method, but rather catch them and fire them as CoercingSerializeException instead as per the method contract.
    
    Parameters:
    
    dataFetcherResult - is never null
    
    Returns:
    
    a serialized value which may be null.
    
    Throws:
    
    CoercingSerializeException - if value input can't be serialized
  - serialize
```
default @Nullable O serialize(@NonNull java.lang.Object dataFetcherResult,
                              @NonNull GraphQLContext graphQLContext,
                              @NonNull java.util.Locale locale)
                       throws CoercingSerializeException
```
    Called to convert a Java object result of a DataFetcher to a valid runtime value for the scalar type.
    Note : Throw CoercingSerializeException if there is fundamental problem during serialization, don't return null to indicate failure.
    Note : You should not allow RuntimeExceptions to come out of your serialize method, but rather catch them and fire them as CoercingSerializeException instead as per the method contract.
    
    Parameters:
    
    dataFetcherResult - is never null
    
    graphQLContext - the graphql context in place
    
    locale - the locale to use
    
    Returns:
    
    a serialized value which may be null.
    
    Throws:
    
    CoercingSerializeException - if value input can't be serialized
  - parseValue
```
@Deprecated(since="2022-08-22")
default @Nullable I parseValue(@NonNull java.lang.Object input)
                        throws CoercingParseValueException
```
    Deprecated.
    
    This is deprecated and you should implement parseValue(Object, GraphQLContext, Locale) instead
    Called to resolve an input from a query variable into a Java object acceptable for the scalar type.
    Note : You should not allow RuntimeExceptions to come out of your parseValue method, but rather catch them and fire them as CoercingParseValueException instead as per the method contract.
    Note : if input is explicit/raw value null, input coercion will return null before this method is called
    
    Parameters:
    
    input - is never null
    
    Returns:
    
    a parsed value which may be null
    
    Throws:
    
    CoercingParseValueException - if value input can't be parsed
  - parseValue
```
default @Nullable I parseValue(@NonNull java.lang.Object input,
                               @NonNull GraphQLContext graphQLContext,
                               @NonNull java.util.Locale locale)
                        throws CoercingParseValueException
```
    Called to resolve an input from a query variable into a Java object acceptable for the scalar type.
    Note : You should not allow RuntimeExceptions to come out of your parseValue method, but rather catch them and fire them as CoercingParseValueException instead as per the method contract. Note : if input is explicit/raw value null, input coercion will return null before this method is called
    
    Parameters:
    
    input - is never null
    
    graphQLContext - the graphql context in place
    
    locale - the locale to use
    
    Returns:
    
    a parsed value which may be null
    
    Throws:
    
    CoercingParseValueException - if value input can't be parsed
  - parseLiteral
```
@Deprecated(since="2022-08-22")
default @Nullable I parseLiteral(@NonNull java.lang.Object input)
                          throws CoercingParseLiteralException
```
    Deprecated.
    
    This is deprecated and you should implement parseLiteral(Value, CoercedVariables, GraphQLContext, Locale) instead
    Called during query validation to convert a query input AST node into a Java object acceptable for the scalar type. The input object will be an instance of Value.
    Note : You should not allow RuntimeExceptions to come out of your parseLiteral method, but rather catch them and fire them as CoercingParseLiteralException instead as per the method contract.
    Note : if input is literal NullValue, input coercion will return null before this method is called
    
    Parameters:
    
    input - is never null
    
    Returns:
    
    a parsed value which may be null
    
    Throws:
    
    CoercingParseLiteralException - if input literal can't be parsed
  - parseLiteral
```
@Deprecated(since="2022-08-22")
default @Nullable I parseLiteral(java.lang.Object input,
                                 java.util.Map<java.lang.String,java.lang.Object> variables)
                          throws CoercingParseLiteralException
```
    Deprecated.
    
    This is deprecated and you should implement parseLiteral(Value, CoercedVariables, GraphQLContext, Locale) instead
    Called during query execution to convert a query input AST node into a Java object acceptable for the scalar type. The input object will be an instance of Value.
    Note : You should not allow RuntimeExceptions to come out of your parseLiteral method, but rather catch them and fire them as CoercingParseLiteralException instead as per the method contract.
    Many scalar types don't need to implement this method because they don't take AST VariableReference objects and convert them into actual values. But for those scalar types that want to do this, then this method should be implemented. Note : if input is literal NullValue, input coercion will return null before this method is called
    
    Parameters:
    
    input - is never null
    
    variables - the resolved variables passed to the query
    
    Returns:
    
    a parsed value which may be null
    
    Throws:
    
    CoercingParseLiteralException - if input literal can't be parsed
  - parseLiteral
```
default @Nullable I parseLiteral(@NonNull Value<?> input,
                                 @NonNull CoercedVariables variables,
                                 @NonNull GraphQLContext graphQLContext,
                                 @NonNull java.util.Locale locale)
                          throws CoercingParseLiteralException
```
    Called during query execution to convert a query input AST node into a Java object acceptable for the scalar type. The input object will be an instance of Value.
    Note : You should not allow RuntimeExceptions to come out of your parseLiteral method, but rather catch them and fire them as CoercingParseLiteralException instead as per the method contract.
    Many scalar types don't need to implement this method because they don't take AST VariableReference objects and convert them into actual values. But for those scalar types that want to do this, then this method should be implemented. Note : if input is literal NullValue, input coercion will return null before this method is called
    
    Parameters:
    
    input - is never null
    
    variables - the resolved variables passed to the query
    
    graphQLContext - the graphql context in place
    
    locale - the locale to use
    
    Returns:
    
    a parsed value which may be null
    
    Throws:
    
    CoercingParseLiteralException - if input literal can't be parsed
  - valueToLiteral
```
@Deprecated(since="2022-08-22")
default @NonNull Value valueToLiteral(@NonNull java.lang.Object input)
```
    Deprecated.
    
    This is deprecated and you should implement valueToLiteral(Object, GraphQLContext, Locale) instead
    Converts an external input value to a literal (Ast Value).
    IMPORTANT: the argument is validated before by calling parseValue(Object).
    
    Parameters:
    
    input - an external input value
    
    Returns:
    
    The literal matching the external input value.
  - valueToLiteral
```
default @NonNull Value<?> valueToLiteral(@NonNull java.lang.Object input,
                                         @NonNull GraphQLContext graphQLContext,
                                         @NonNull java.util.Locale locale)
```
    Converts an external input value to a literal (Ast Value).
    IMPORTANT: the argument is validated before by calling parseValue(Object).
    
    Parameters:
    
    input - an external input value
    
    graphQLContext - the graphql context in place
    
    locale - the locale to use
    
    Returns:
    
    The literal matching the external input value.

Interface Coercing<I,​O>

Method Summary

Method Detail

serialize

serialize

parseValue

parseValue

parseLiteral

parseLiteral

parseLiteral

valueToLiteral

valueToLiteral

Interface Coercing<I,O>