public abstract class Transformer extends Object
An instance of this class can be obtained with the TransformerFactory.newTransformer
method. This instance may then be used to process XML from a variety of sources and write the transformation output to a variety of sinks.
An object of this class may not be used in multiple threads running concurrently. Different Transformers may be used concurrently by different threads.
A Transformer
may be used multiple times. Parameters and output properties are preserved across transformations.
Modifier | Constructor | Description |
---|---|---|
protected |
Default constructor is protected on purpose. |
Modifier and Type | Method | Description |
---|---|---|
abstract void |
clearParameters() |
Clear all parameters set with setParameter. |
abstract ErrorListener |
getErrorListener() |
Get the error event handler in effect for the transformation. |
abstract Properties |
getOutputProperties() |
Get a copy of the output properties for the transformation. |
abstract String |
getOutputProperty |
Get an output property that is in effect for the transformer. |
abstract Object |
getParameter |
Get a parameter that was explicitly set with setParameter. |
abstract URIResolver |
getURIResolver() |
Get an object that will be used to resolve URIs used in document(). |
void |
reset() |
Reset this Transformer to its original configuration. |
abstract void |
setErrorListener |
Set the error event listener in effect for the transformation. |
abstract void |
setOutputProperties |
Set the output properties for the transformation. |
abstract void |
setOutputProperty |
Set an output property that will be in effect for the transformation. |
abstract void |
setParameter |
Add a parameter for the transformation. |
abstract void |
setURIResolver |
Set an object that will be used to resolve URIs used in document(). |
abstract void |
transform |
Transform the XML Source to a Result . |
protected Transformer()
public void reset()
Reset this Transformer
to its original configuration.
Transformer
is reset to the same state as when it was created with TransformerFactory.newTransformer()
, TransformerFactory.newTransformer(Source source)
or Templates.newTransformer()
. reset()
is designed to allow the reuse of existing Transformer
s thus saving resources associated with the creation of new Transformer
s.
The reset Transformer
is not guaranteed to have the same URIResolver
or ErrorListener
Object
s, e.g. Object.equals(Object obj)
. It is guaranteed to have a functionally equal URIResolver
and ErrorListener
.
UnsupportedOperationException
- When implementation does not override this method.public abstract void transform(Source xmlSource, Result outputTarget) throws TransformerException
Transform the XML Source
to a Result
. Specific transformation behavior is determined by the settings of the TransformerFactory
in effect when the Transformer
was instantiated and any modifications made to the Transformer
instance.
An empty Source
is represented as an empty document as constructed by DocumentBuilder.newDocument()
. The result of transforming an empty Source
depends on the transformation behavior; it is not always an empty Result
.
xmlSource
- The XML input to transform.outputTarget
- The Result
of transforming the xmlSource
.TransformerException
- If an unrecoverable error occurs during the course of the transformation.public abstract void setParameter(String name, Object value)
Pass a qualified name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.
For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.
name
- The name of the parameter, which may begin with a namespace URI in curly braces ({}).value
- The value object. This can be any valid Java object. It is up to the processor to provide the proper object conversion or to simply pass the object on for use in an extension.NullPointerException
- If value is null.public abstract Object getParameter(String name)
This method does not return a default parameter value, which cannot be determined until the node context is evaluated during the transformation process.
name
- of Object
to getpublic abstract void clearParameters()
public abstract void setURIResolver(URIResolver resolver)
If the resolver argument is null, the URIResolver value will be cleared and the transformer will no longer have a resolver.
resolver
- An object that implements the URIResolver interface, or null.public abstract URIResolver getURIResolver()
public abstract void setOutputProperties(Properties oformat)
If argument to this function is null, any properties previously set are removed, and the value will revert to the value defined in the templates object.
Pass a qualified property key name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.
For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.
AnIllegalArgumentException
is thrown if any of the argument keys are not recognized and are not namespace qualified.oformat
- A set of output properties that will be used to override any of the same properties in affect for the transformation.IllegalArgumentException
- When keys are not recognized and are not namespace qualified.public abstract Properties getOutputProperties()
Get a copy of the output properties for the transformation.
The properties returned should contain properties set by the user, and properties set by the stylesheet, and these properties are "defaulted" by default properties specified by section 16 of the XSL Transformations (XSLT) W3C Recommendation. The properties that were specifically set by the user or the stylesheet should be in the base Properties list, while the XSLT default properties that were not specifically set should be the default Properties list. Thus, getOutputProperties().getProperty(String key) will obtain any property in that was set by setOutputProperty(java.lang.String, java.lang.String)
, setOutputProperties(java.util.Properties)
, in the stylesheet, or the default properties, while getOutputProperties().get(String key) will only retrieve properties that were explicitly set by setOutputProperty(java.lang.String, java.lang.String)
, setOutputProperties(java.util.Properties)
, or in the stylesheet.
Note that mutation of the Properties object returned will not effect the properties that the transformer contains.
If any of the argument keys are not recognized and are not namespace qualified, the property will be ignored and not returned. In other words the behaviour is not orthogonal with setOutputProperties
.
public abstract void setOutputProperty(String name, String value) throws IllegalArgumentException
Pass a qualified property name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.
For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.
The Properties object that was passed to setOutputProperties(java.util.Properties)
won't be effected by calling this method.
name
- A non-null String that specifies an output property name, which may be namespace qualified.value
- The non-null string value of the output property.IllegalArgumentException
- If the property is not supported, and is not qualified with a namespace.public abstract String getOutputProperty(String name) throws IllegalArgumentException
Get an output property that is in effect for the transformer.
If a property has been set using setOutputProperty(java.lang.String, java.lang.String)
, that value will be returned. Otherwise, if a property is explicitly specified in the stylesheet, that value will be returned. If the value of the property has been defaulted, that is, if no value has been set explicitly either with setOutputProperty(java.lang.String, java.lang.String)
or in the stylesheet, the result may vary depending on implementation and input stylesheet.
name
- A non-null String that specifies an output property name, which may be namespace qualified.IllegalArgumentException
- If the property is not supported.public abstract void setErrorListener(ErrorListener listener) throws IllegalArgumentException
listener
- The new error listener.IllegalArgumentException
- if listener is null.public abstract ErrorListener getErrorListener()
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https://docs.oracle.com/en/java/javase/21/docs/api/java.xml/javax/xml/transform/Transformer.html