Package com.fasterxml.jackson.databind.deser

Class ValueInstantiator

java.lang.Object

com.fasterxml.jackson.databind.deser.ValueInstantiator

Direct Known Subclasses:

StdValueInstantiator, ValueInstantiator.Base, ValueInstantiator.Delegating

public abstract class ValueInstantiator
extends Object

Class that defines simple API implemented by objects that create value instances. Some or all of properties of value instances may be initialized by instantiator, rest being populated by deserializer, to which value instance is passed. Since different kinds of JSON values (structured and scalar) may be bound to Java values, in some cases instantiator fully defines resulting value; this is the case when JSON value is a scalar value (String, number, boolean).

Note that this type is not parameterized (even though it would seemingly make sense), because such type information cannot be use effectively during runtime: access is always using either wildcard type, or just basic Object; and so adding type parameter seems like unnecessary extra work.

Actual implementations are strongly recommended to be based on StdValueInstantiator which implements all methods, and as such will be compatible across versions even if new methods were added to this interface.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ValueInstantiator.Base	Partial ValueInstantiator implementation that is strongly recommended to be used instead of directly extending ValueInstantiator itself.
static class	ValueInstantiator.Delegating	Delegating ValueInstantiator implementation meant as a base type that by default delegates methods to specified fallback instantiator.
static interface	ValueInstantiator.Gettable

Constructor Summary

Constructors

Constructor	Description
ValueInstantiator()

Method Summary

Modifier and Type	Method	Description
boolean	canCreateFromBigDecimal()	Method that can be called to check whether a BigDecimal based creator is available to use (to call createFromBigDecimal(com.fasterxml.jackson.databind.DeserializationContext, java.math.BigDecimal)).
boolean	canCreateFromBigInteger()	Method that can be called to check whether a BigInteger based creator is available to use (to call createFromBigInteger(com.fasterxml.jackson.databind.DeserializationContext, java.math.BigInteger)).
boolean	canCreateFromBoolean()	Method that can be called to check whether a double (boolean / Boolean) based creator is available to use (to call createFromDouble(com.fasterxml.jackson.databind.DeserializationContext, double)).
boolean	canCreateFromDouble()	Method that can be called to check whether a double (double / Double) based creator is available to use (to call createFromDouble(com.fasterxml.jackson.databind.DeserializationContext, double)).
boolean	canCreateFromInt()	Method that can be called to check whether an integer (int, Integer) based creator is available to use (to call createFromInt(com.fasterxml.jackson.databind.DeserializationContext, int)).
boolean	canCreateFromLong()	Method that can be called to check whether a long (long, Long) based creator is available to use (to call createFromLong(com.fasterxml.jackson.databind.DeserializationContext, long)).
boolean	canCreateFromObjectWith()	Method that can be called to check whether a property-based creator (argument-taking constructor or factory method) is available to instantiate values from JSON Object
boolean	canCreateFromString()	Method that can be called to check whether a String-based creator is available for this instantiator.
boolean	canCreateUsingArrayDelegate()	Method that can be called to check whether a array-delegate-based creator (single-arg constructor or factory method) is available for this instantiator
boolean	canCreateUsingDefault()	Method that can be called to check whether a default creator (constructor, or no-arg static factory method) is available for this instantiator
boolean	canCreateUsingDelegate()	Method that can be called to check whether a delegate-based creator (single-arg constructor or factory method) is available for this instantiator
boolean	canInstantiate()	Method that will return true if any of canCreateXxx method returns true: that is, if there is any way that an instance could be created.
ValueInstantiator	createContextual(DeserializationContext ctxt, BeanDescription beanDesc)	"Contextualization" method that is called after construction but before first use, to allow instantiator access to context needed to possible resolve its dependencies.
Object	createFromBigDecimal(DeserializationContext ctxt, BigDecimal value)
Object	createFromBigInteger(DeserializationContext ctxt, BigInteger value)
Object	createFromBoolean(DeserializationContext ctxt, boolean value)
Object	createFromDouble(DeserializationContext ctxt, double value)
Object	createFromInt(DeserializationContext ctxt, int value)
Object	createFromLong(DeserializationContext ctxt, long value)
Object	createFromObjectWith(DeserializationContext ctxt, SettableBeanProperty[] props, PropertyValueBuffer buffer)	Method that delegates to createFromObjectWith(DeserializationContext, Object[]) by default, but can be overridden if the application should have customized behavior with respect to missing properties.
Object	createFromObjectWith(DeserializationContext ctxt, Object[] args)	Method called to create value instance from JSON Object when instantiation arguments are passed; this is done, for example when passing information specified with "Creator" annotations.
Object	createFromString(DeserializationContext ctxt, String value)
Object	createUsingArrayDelegate(DeserializationContext ctxt, Object delegate)	Method to called to create value instance from JSON Array using an intermediate "delegate" value to pass to createor method
Object	createUsingDefault(DeserializationContext ctxt)	Method called to create value instance from a JSON value when no data needs to passed to creator (constructor, factory method); typically this will call the default constructor of the value object.
Object	createUsingDefaultOrWithoutArguments(DeserializationContext ctxt)	Combination of createUsingDefault(com.fasterxml.jackson.databind.DeserializationContext) and createFromObjectWith(DeserializationContext, Object[]) which will call former first, if possible; or latter if possible (with null arguments); and if neither works throw an exception.
Object	createUsingDelegate(DeserializationContext ctxt, Object delegate)	Method to called to create value instance from JSON Object using an intermediate "delegate" value to pass to createor method
AnnotatedWithParams	getArrayDelegateCreator()	Method that can be called to try to access member (constructor, static factory method) that is used as the "array delegate creator".
JavaType	getArrayDelegateType(DeserializationConfig config)	Method that can be used to determine what is the type of array delegate type to use, if any; if no delegates are used, will return null.
AnnotatedWithParams	getDefaultCreator()	Method that can be called to try to access member (constructor, static factory method) that is used as the "default creator" (creator that is called without arguments; typically default [zero-argument] constructor of the type).
AnnotatedWithParams	getDelegateCreator()	Method that can be called to try to access member (constructor, static factory method) that is used as the "delegate creator".
JavaType	getDelegateType(DeserializationConfig config)	Method that can be used to determine what is the type of delegate type to use, if any; if no delegates are used, will return null.
SettableBeanProperty[]	getFromObjectArguments(DeserializationConfig config)	Method called to determine types of instantiation arguments to use when creating instances with creator arguments (when canCreateFromObjectWith() returns true).
Class<?>	getValueClass()	Accessor for raw (type-erased) type of instances to create.
String	getValueTypeDesc()	Method that returns description of the value type this instantiator handles.
AnnotatedWithParams	getWithArgsCreator()	Method that can be called to try to access member (constructor, static factory method) that is used as the "non-default creator" (constructor or factory method that takes one or more arguments).

Methods inherited from class java.lang.Object

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

Constructor Details

ValueInstantiator

public ValueInstantiator()

Method Details

createContextual

public ValueInstantiator createContextual(DeserializationContext ctxt,
 BeanDescription beanDesc)
                                   throws JsonMappingException

"Contextualization" method that is called after construction but before first use, to allow instantiator access to context needed to possible resolve its dependencies.

Parameters:

ctxt - Currently active deserialization context: needed to (for example) resolving TypeDeserializers.

Returns:

This instance, if no change, or newly constructed instance

Throws:

JsonMappingException - If there are issues with contextualization

Since:

2.12

getValueClass

public Class<?> getValueClass()

Accessor for raw (type-erased) type of instances to create.

NOTE: since this method has not existed since beginning of Jackson 2.0 series, default implementation will just return Object.class; implementations are expected to override it with real value.

Since:

2.8

getValueTypeDesc

public String getValueTypeDesc()

Method that returns description of the value type this instantiator handles. Used for error messages, diagnostics.

canInstantiate

public boolean canInstantiate()

Method that will return true if any of canCreateXxx method returns true: that is, if there is any way that an instance could be created.

canCreateFromString

public boolean canCreateFromString()

Method that can be called to check whether a String-based creator is available for this instantiator.

NOTE: does NOT include possible case of fallbacks, or coercion; only considers explicit creator.

canCreateFromInt

public boolean canCreateFromInt()

Method that can be called to check whether an integer (int, Integer) based creator is available to use (to call createFromInt(com.fasterxml.jackson.databind.DeserializationContext, int)).

canCreateFromLong

public boolean canCreateFromLong()

Method that can be called to check whether a long (long, Long) based creator is available to use (to call createFromLong(com.fasterxml.jackson.databind.DeserializationContext, long)).

canCreateFromBigInteger

public boolean canCreateFromBigInteger()

Method that can be called to check whether a BigInteger based creator is available to use (to call createFromBigInteger(com.fasterxml.jackson.databind.DeserializationContext, java.math.BigInteger)). +

canCreateFromDouble

public boolean canCreateFromDouble()

Method that can be called to check whether a double (double / Double) based creator is available to use (to call createFromDouble(com.fasterxml.jackson.databind.DeserializationContext, double)).

canCreateFromBigDecimal

public boolean canCreateFromBigDecimal()

Method that can be called to check whether a BigDecimal based creator is available to use (to call createFromBigDecimal(com.fasterxml.jackson.databind.DeserializationContext, java.math.BigDecimal)).

canCreateFromBoolean

public boolean canCreateFromBoolean()

Method that can be called to check whether a double (boolean / Boolean) based creator is available to use (to call createFromDouble(com.fasterxml.jackson.databind.DeserializationContext, double)).

canCreateUsingDefault

public boolean canCreateUsingDefault()

Method that can be called to check whether a default creator (constructor, or no-arg static factory method) is available for this instantiator

canCreateUsingDelegate

public boolean canCreateUsingDelegate()

Method that can be called to check whether a delegate-based creator (single-arg constructor or factory method) is available for this instantiator

canCreateUsingArrayDelegate

public boolean canCreateUsingArrayDelegate()

Method that can be called to check whether a array-delegate-based creator (single-arg constructor or factory method) is available for this instantiator

Since:

2.7

canCreateFromObjectWith

public boolean canCreateFromObjectWith()

Method that can be called to check whether a property-based creator (argument-taking constructor or factory method) is available to instantiate values from JSON Object

getFromObjectArguments

public SettableBeanProperty[] getFromObjectArguments(DeserializationConfig config)

Method called to determine types of instantiation arguments to use when creating instances with creator arguments (when canCreateFromObjectWith() returns true). These arguments are bound from JSON, using specified property types to locate deserializers.

NOTE: all properties will be of type CreatorProperty.

getDelegateType

public JavaType getDelegateType(DeserializationConfig config)

Method that can be used to determine what is the type of delegate type to use, if any; if no delegates are used, will return null. If non-null type is returned, deserializer will bind JSON into specified type (using standard deserializer for that type), and pass that to instantiator.

getArrayDelegateType

public JavaType getArrayDelegateType(DeserializationConfig config)

Method that can be used to determine what is the type of array delegate type to use, if any; if no delegates are used, will return null. If non-null type is returned, deserializer will bind JSON into specified type (using standard deserializer for that type), and pass that to instantiator.

Since:

2.7

createUsingDefault

public Object createUsingDefault(DeserializationContext ctxt)
                          throws IOException

Method called to create value instance from a JSON value when no data needs to passed to creator (constructor, factory method); typically this will call the default constructor of the value object. It will only be used if more specific creator methods are not applicable; hence "default".

This method is called if getFromObjectArguments(com.fasterxml.jackson.databind.DeserializationConfig) returns null or empty List.

Throws:

IOException

createFromObjectWith

public Object createFromObjectWith(DeserializationContext ctxt,
 Object[] args)
                            throws IOException

Method called to create value instance from JSON Object when instantiation arguments are passed; this is done, for example when passing information specified with "Creator" annotations.

This method is called if getFromObjectArguments(com.fasterxml.jackson.databind.DeserializationConfig) returns a non-empty List of arguments.

Throws:

IOException

createUsingDefaultOrWithoutArguments

public Object createUsingDefaultOrWithoutArguments(DeserializationContext ctxt)
                                            throws IOException

Combination of createUsingDefault(com.fasterxml.jackson.databind.DeserializationContext) and createFromObjectWith(DeserializationContext, Object[]) which will call former first, if possible; or latter if possible (with null arguments); and if neither works throw an exception.

Throws:

IOException

Since:

2.15

createFromObjectWith

public Object createFromObjectWith(DeserializationContext ctxt,
 SettableBeanProperty[] props,
 PropertyValueBuffer buffer)
                            throws IOException

Method that delegates to createFromObjectWith(DeserializationContext, Object[]) by default, but can be overridden if the application should have customized behavior with respect to missing properties.

The default implementation of this method uses PropertyValueBuffer.getParameters(SettableBeanProperty[]) to read and validate all properties in bulk, possibly substituting defaults for missing properties or throwing exceptions for missing properties. An overridden implementation of this method could, for example, use PropertyValueBuffer.hasParameter(SettableBeanProperty) and PropertyValueBuffer.getParameter(SettableBeanProperty) to safely read the present properties only, and to have some other behavior for the missing properties.

Throws:

IOException

Since:

2.8

createUsingDelegate

public Object createUsingDelegate(DeserializationContext ctxt,
 Object delegate)
                           throws IOException

Method to called to create value instance from JSON Object using an intermediate "delegate" value to pass to createor method

Throws:

IOException

createUsingArrayDelegate

public Object createUsingArrayDelegate(DeserializationContext ctxt,
 Object delegate)
                                throws IOException

Method to called to create value instance from JSON Array using an intermediate "delegate" value to pass to createor method

Throws:

IOException

createFromString

public Object createFromString(DeserializationContext ctxt,
 String value)
                        throws IOException

Throws:

IOException

createFromInt

public Object createFromInt(DeserializationContext ctxt,
 int value)
                     throws IOException

Throws:

IOException

createFromLong

public Object createFromLong(DeserializationContext ctxt,
 long value)
                      throws IOException

Throws:

IOException

createFromBigInteger

public Object createFromBigInteger(DeserializationContext ctxt,
 BigInteger value)
                            throws IOException

Throws:

IOException

createFromDouble

public Object createFromDouble(DeserializationContext ctxt,
 double value)
                        throws IOException

Throws:

IOException

createFromBigDecimal

public Object createFromBigDecimal(DeserializationContext ctxt,
 BigDecimal value)
                            throws IOException

Throws:

IOException

createFromBoolean

public Object createFromBoolean(DeserializationContext ctxt,
 boolean value)
                         throws IOException

Throws:

IOException

getDefaultCreator

public AnnotatedWithParams getDefaultCreator()

Method that can be called to try to access member (constructor, static factory method) that is used as the "default creator" (creator that is called without arguments; typically default [zero-argument] constructor of the type). Note that implementations not required to return actual object they use (or, they may use some other instantiation) method. That is, even if canCreateUsingDefault() returns true, this method may return null .

getDelegateCreator

public AnnotatedWithParams getDelegateCreator()

Method that can be called to try to access member (constructor, static factory method) that is used as the "delegate creator". Note that implementations not required to return actual object they use (or, they may use some other instantiation) method. That is, even if canCreateUsingDelegate() returns true, this method may return null .

getArrayDelegateCreator

public AnnotatedWithParams getArrayDelegateCreator()

Method that can be called to try to access member (constructor, static factory method) that is used as the "array delegate creator". Note that implementations not required to return actual object they use (or, they may use some other instantiation) method. That is, even if canCreateUsingArrayDelegate() returns true, this method may return null .

getWithArgsCreator

public AnnotatedWithParams getWithArgsCreator()

Method that can be called to try to access member (constructor, static factory method) that is used as the "non-default creator" (constructor or factory method that takes one or more arguments). Note that implementations not required to return actual object they use (or, they may use some other instantiation) method. That is, even if canCreateFromObjectWith() returns true, this method may return null .