public abstract class Validator extends Object
A processor that checks an XML document against Schema
.
A validator object is not thread-safe and not reentrant.
In other words, it is the application's responsibility to make
sure that one Validator
object is not used from
more than one thread at any given time, and while the validate
method is invoked, applications may not recursively call
the validate
method.
Modifier | Constructor and Description |
---|---|
protected |
Validator()
Constructor for derived classes.
|
Modifier and Type | Method and Description |
---|---|
abstract ErrorHandler |
getErrorHandler()
Gets the current
ErrorHandler set to this Validator . |
boolean |
getFeature(String name)
Look up the value of a feature flag.
|
Object |
getProperty(String name)
Look up the value of a property.
|
abstract LSResourceResolver |
getResourceResolver()
Gets the current
LSResourceResolver set to this Validator . |
abstract void |
reset()
Reset this
Validator to its original configuration. |
abstract void |
setErrorHandler(ErrorHandler errorHandler)
Sets the
ErrorHandler to receive errors encountered
during the validate method invocation. |
void |
setFeature(String name,
boolean value)
Set the value of a feature flag.
|
void |
setProperty(String name,
Object object)
Set the value of a property.
|
abstract void |
setResourceResolver(LSResourceResolver resourceResolver)
Sets the
LSResourceResolver to customize
resource resolution while in a validation episode. |
void |
validate(Source source)
Validates the specified input.
|
abstract void |
validate(Source source,
Result result)
Validates the specified input and send the augmented validation
result to the specified output.
|
protected Validator()
The constructor does nothing.
Derived classes must create Validator
objects that have
null
ErrorHandler
and
null
LSResourceResolver
.
public abstract void reset()
Reset this Validator
to its original configuration.
Validator
is reset to the same state as when it was created with
Schema.newValidator()
.
reset()
is designed to allow the reuse of existing Validator
s
thus saving resources associated with the creation of new Validator
s.
The reset Validator
is not guaranteed to have the same LSResourceResolver
or ErrorHandler
Object
s, e.g. Object.equals(Object obj)
. It is guaranteed to have a functionally equal
LSResourceResolver
and ErrorHandler
.
public void validate(Source source) throws SAXException, IOException
This is just a convenience method for
validate(Source source, Result result)
with result
of null
.
source
- XML to be validated. Must be an XML document or
XML element and must not be null. For backwards compatibility,
the results of attempting to validate anything other than
a document or element are implementation-dependent.
Implementations must either recognize and process the input
or throw an IllegalArgumentException.IllegalArgumentException
- If the Source
is an XML artifact that the implementation cannot
validate (for example, a processing instruction).SAXException
- If the ErrorHandler
throws a SAXException
or
if a fatal error is found and the ErrorHandler
returns
normally.IOException
- If the validator is processing a
SAXSource
and the
underlying XMLReader
throws an
IOException
.NullPointerException
- If source
is
null
.validate(Source source, Result result)
public abstract void validate(Source source, Result result) throws SAXException, IOException
Validates the specified input and send the augmented validation result to the specified output.
This method places the following restrictions on the types of
the Source
/Result
accepted.
Source / Result Accepted |
||||
---|---|---|---|---|
StreamSource |
SAXSource |
DOMSource |
StAXSource |
|
null |
OK | OK | OK | OK |
StreamResult |
OK | IllegalArgumentException |
IllegalArgumentException |
IllegalArgumentException |
SAXResult |
IllegalArgumentException |
OK | IllegalArgumentException |
IllegalArgumentException |
DOMResult |
IllegalArgumentException |
IllegalArgumentException |
OK | IllegalArgumentException |
StAXResult |
IllegalArgumentException |
IllegalArgumentException |
IllegalArgumentException |
OK |
To validate one Source
into another kind of
Result
, use the identity transformer (see
TransformerFactory.newTransformer()
).
Errors found during the validation is sent to the specified
ErrorHandler
.
If a document is valid, or if a document contains some errors
but none of them were fatal and the ErrorHandler
didn't
throw any exception, then the method returns normally.
source
- XML to be validated. Must be an XML document or
XML element and must not be null. For backwards compatibility,
the results of attempting to validate anything other than
a document or element are implementation-dependent.
Implementations must either recognize and process the input
or throw an IllegalArgumentException.result
- The Result
object that receives (possibly augmented)
XML. This parameter can be null if the caller is not interested
in it.
Note that when a DOMResult
is used,
a validator might just pass the same DOM node from
DOMSource
to DOMResult
(in which case source.getNode()==result.getNode()
),
it might copy the entire DOM tree, or it might alter the
node given by the source.IllegalArgumentException
- If the Result
type doesn't match the
Source
type of if the Source
is an XML artifact that the implementation cannot
validate (for example, a processing instruction).SAXException
- If the ErrorHandler
throws a
SAXException
or
if a fatal error is found and the ErrorHandler
returns
normally.IOException
- If the validator is processing a
SAXSource
and the
underlying XMLReader
throws an
IOException
.NullPointerException
- If the source
parameter is null
.validate(Source source)
public abstract void setErrorHandler(ErrorHandler errorHandler)
ErrorHandler
to receive errors encountered
during the validate
method invocation.
Error handler can be used to customize the error handling process
during a validation. When an ErrorHandler
is set,
errors found during the validation will be first sent
to the ErrorHandler
.
The error handler can abort further validation immediately
by throwing SAXException
from the handler. Or for example
it can print an error to the screen and try to continue the
validation by returning normally from the ErrorHandler
If any Throwable
is thrown from an ErrorHandler
,
the caller of the validate
method will be thrown
the same Throwable
object.
Validator
is not allowed to
throw SAXException
without first reporting it to
ErrorHandler
.
When the ErrorHandler
is null, the implementation will
behave as if the following ErrorHandler
is set:
class DraconianErrorHandler implementsErrorHandler
{ public void fatalError(SAXParseException
e ) throwsSAXException
{ throw e; } public void error(SAXParseException
e ) throwsSAXException
{ throw e; } public void warning(SAXParseException
e ) throwsSAXException
{ // noop } }
When a new Validator
object is created, initially
this field is set to null.
errorHandler
- A new error handler to be set. This parameter can be null.public abstract ErrorHandler getErrorHandler()
ErrorHandler
set to this Validator
.setErrorHandler(ErrorHandler)
method, or null
if that method has never been called since this Validator
has created.setErrorHandler(ErrorHandler)
public abstract void setResourceResolver(LSResourceResolver resourceResolver)
LSResourceResolver
to customize
resource resolution while in a validation episode.
Validator
uses a LSResourceResolver
when it needs to locate external resources while a validation,
although exactly what constitutes "locating external resources" is
up to each schema language.
When the LSResourceResolver
is null, the implementation will
behave as if the following LSResourceResolver
is set:
class DumbLSResourceResolver implementsLSResourceResolver
{ publicLSInput
resolveResource( String publicId, String systemId, String baseURI) { return null; // always return null } }
If a LSResourceResolver
throws a RuntimeException
(or instances of its derived classes),
then the Validator
will abort the parsing and
the caller of the validate
method will receive
the same RuntimeException
.
When a new Validator
object is created, initially
this field is set to null.
resourceResolver
- A new resource resolver to be set. This parameter can be null.public abstract LSResourceResolver getResourceResolver()
LSResourceResolver
set to this Validator
.setResourceResolver(LSResourceResolver)
method, or null
if that method has never been called since this Validator
has created.setErrorHandler(ErrorHandler)
public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException
The feature name is any fully-qualified URI. It is
possible for a Validator
to recognize a feature name but
temporarily be unable to return its value.
Some feature values may be available only in specific
contexts, such as before, during, or after a validation.
Implementors are free (and encouraged) to invent their own features, using names built on their own URIs.
name
- The feature name, which is a non-null fully-qualified URI.SAXNotRecognizedException
- If the feature
value can't be assigned or retrieved.SAXNotSupportedException
- When the
Validator
recognizes the feature name but
cannot determine its value at this time.NullPointerException
- When the name parameter is null.setFeature(String, boolean)
public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException
Feature can be used to control the way a Validator
parses schemas, although Validator
s are not required
to recognize any specific feature names.
The feature name is any fully-qualified URI. It is
possible for a Validator
to expose a feature value but
to be unable to change the current value.
Some feature values may be immutable or mutable only
in specific contexts, such as before, during, or after
a validation.
name
- The feature name, which is a non-null fully-qualified URI.value
- The requested value of the feature (true or false).SAXNotRecognizedException
- If the feature
value can't be assigned or retrieved.SAXNotSupportedException
- When the
Validator
recognizes the feature name but
cannot set the requested value.NullPointerException
- When the name parameter is null.getFeature(String)
public void setProperty(String name, Object object) throws SAXNotRecognizedException, SAXNotSupportedException
The property name is any fully-qualified URI. It is
possible for a Validator
to recognize a property name but
to be unable to change the current value.
Some property values may be immutable or mutable only
in specific contexts, such as before, during, or after
a validation.
All implementations that implement JAXP 1.5 or newer are required to
support the XMLConstants.ACCESS_EXTERNAL_DTD
and
XMLConstants.ACCESS_EXTERNAL_SCHEMA
properties.
Access to external DTDs in source or Schema file is restricted to
the protocols specified by the XMLConstants.ACCESS_EXTERNAL_DTD
property. If access is denied during validation due to the restriction
of this property, SAXException
will be thrown by the
validate(Source)
method.
Access to external reference set by the schemaLocation attribute is
restricted to the protocols specified by the
XMLConstants.ACCESS_EXTERNAL_SCHEMA
property.
If access is denied during validation due to the restriction of this property,
SAXException
will be thrown by the
validate(Source)
method.
name
- The property name, which is a non-null fully-qualified URI.object
- The requested value for the property.SAXNotRecognizedException
- If the property
value can't be assigned or retrieved.SAXNotSupportedException
- When the
Validator
recognizes the property name but
cannot set the requested value.NullPointerException
- When the name parameter is null.public Object getProperty(String name) throws SAXNotRecognizedException, SAXNotSupportedException
The property name is any fully-qualified URI. It is
possible for a Validator
to recognize a property name but
temporarily be unable to return its value.
Some property values may be available only in specific
contexts, such as before, during, or after a validation.
Validator
s are not required to recognize any specific
property names.
Implementors are free (and encouraged) to invent their own properties, using names built on their own URIs.
name
- The property name, which is a non-null fully-qualified URI.SAXNotRecognizedException
- If the property
value can't be assigned or retrieved.SAXNotSupportedException
- When the
XMLReader recognizes the property name but
cannot determine its value at this time.NullPointerException
- When the name parameter is null.setProperty(String, Object)
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