Class Transformer
java.lang.Object
org.simpleframework.xml.transform.Transformer
The
Transformer
object is used to convert strings to
and from object instances. This is used during the serialization
and deserialization process to transform types from the Java class
libraries, as well as other types which do not contain XML schema
annotations. Typically this will be used to transform primitive
types to and from strings, such as int
values.
@Element private String[] value;For example taking the above value the array of strings needs to be converted in to a single string value that can be inserted in to the element in such a way that in can be read later. In this case the serialized value of the string array would be as follows.
<value>one, two, three</value>Here each non-null string is inserted in to a comma separated list of values, which can later be deserialized. Just to note the above array could be annotated with
ElementList
just
as easily, in which case each entry would have its own element.
The choice of which annotation to use is up to the developer. A
more obvious benefit to transformations like this can be seen for
values annotated with the Attribute
annotation.-
Field Summary
FieldsModifier and TypeFieldDescriptionThis is used to cache all transforms matched to a given type.This is used to cache the types that to not have a transform.private final Matcher
This is used to perform the matching of types to transforms. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate Transform
This method is used to acquire aTransform
for the the specified type.private Transform
This method is used to acquire aTransform
for the the specified type.This method is used to convert the string value given to an appropriate representation.boolean
This method is used to determine if the type specified can be transformed.This method is used to convert the provided value into an XML usable format.
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Field Details
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cache
This is used to cache all transforms matched to a given type. -
error
This is used to cache the types that to not have a transform. -
matcher
This is used to perform the matching of types to transforms.
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Constructor Details
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Transformer
Constructor for theTransformer
object. This is used to create a transformer which will transform specified types using transforms loaded from the class path. Transforms are matched to types using the specified matcher object.- Parameters:
matcher
- this is used to match types to transforms
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Method Details
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read
This method is used to convert the string value given to an appropriate representation. This is used when an object is being deserialized from the XML document and the value for the string representation is required.- Parameters:
value
- this is the string representation of the valuetype
- this is the type to convert the string value to- Returns:
- this returns an appropriate instanced to be used
- Throws:
Exception
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write
This method is used to convert the provided value into an XML usable format. This is used in the serialization process when there is a need to convert a field value in to a string so that that value can be written as a valid XML entity.- Parameters:
value
- this is the value to be converted to a stringtype
- this is the type to convert to a string value- Returns:
- this is the string representation of the given value
- Throws:
Exception
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valid
This method is used to determine if the type specified can be transformed. This will use theMatcher
to find a suitable transform, if one exists then this returns true, if not then this returns false. This is used during serialization to determine how to convert a field or method parameter.- Parameters:
type
- the type to determine whether its transformable- Returns:
- true if the type specified can be transformed by this
- Throws:
Exception
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lookup
This method is used to acquire aTransform
for the the specified type. If there is no transform for the type then this will return null. Once acquired once the transform is cached so that subsequent lookups will be performed faster.- Parameters:
type
- the type to determine whether its transformable- Returns:
- this will return a transform for the specified type
- Throws:
Exception
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match
This method is used to acquire aTransform
for the the specified type. If there is no transform for the type then this will return null. Once acquired once the transform is cached so that subsequent lookups will be performed faster.- Parameters:
type
- the type to determine whether its transformable- Returns:
- this will return a transform for the specified type
- Throws:
Exception
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