javax.xml.bind.JAXB Maven / Gradle / Ivy
package javax.xml.bind;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.namespace.QName;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import java.beans.Introspector;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
/**
* Class that defines convenience methods for common, simple use of JAXB.
*
*
* Methods defined in this class are convenience methods that combine several basic operations
* in the {@link JAXBContext}, {@link Unmarshaller}, and {@link Marshaller}.
*
* They are designed
* to be the prefered methods for developers new to JAXB. They have
* the following characterstics:
*
*
* - Generally speaking, the performance is not necessarily optimal.
* It is expected that people who need to write performance
* critical code will use the rest of the JAXB API directly.
*
- Errors that happen during the processing is wrapped into
* {@link DataBindingException} (which will have {@link JAXBException}
* as its {@link Throwable#getCause() cause}. It is expected that
* people who prefer the checked exception would use
* the rest of the JAXB API directly.
*
*
*
* In addition, the unmarshal methods have the following characteristic:
*
*
* - Schema validation is not performed on the input XML.
* The processing will try to continue even if there
* are errors in the XML, as much as possible. Only as
* the last resort, this method fails with {@link DataBindingException}.
*
*
*
* Similarly, the marshal methods have the following characteristic:
*
* - The processing will try to continue even if the Java object tree
* does not meet the validity requirement. Only as
* the last resort, this method fails with {@link DataBindingException}.
*
*
*
*
* All the methods on this class require non-null arguments to all parameters.
* The unmarshal methods either fail with an exception or return
* a non-null value.
*
* @author Kohsuke Kawaguchi
* @since 2.1
*/
public final class JAXB {
/**
* No instanciation is allowed.
*/
private JAXB() {}
/**
* To improve the performance, we'll cache the last {@link JAXBContext} used.
*/
private static final class Cache {
final Class type;
final JAXBContext context;
public Cache(Class type) throws JAXBException {
this.type = type;
this.context = JAXBContext.newInstance(type);
}
}
/**
* Cache. We don't want to prevent the {@link Cache#type} from GC-ed,
* hence {@link WeakReference}.
*/
private static volatile WeakReference cache;
/**
* Obtains the {@link JAXBContext} from the given type,
* by using the cache if possible.
*
*
* We don't use locks to control access to {@link #cache}, but this code
* should be thread-safe thanks to the immutable {@link Cache} and {@code volatile}.
*/
private static JAXBContext getContext(Class type) throws JAXBException {
WeakReference c = cache;
if(c!=null) {
Cache d = c.get();
if(d!=null && d.type==type)
return d.context;
}
// overwrite the cache
Cache d = new Cache(type);
cache = new WeakReference(d);
return d.context;
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* Reads the entire file as XML.
*/
public static T unmarshal( File xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(new StreamSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The resource pointed by the URL is read in its entirety.
*/
public static T unmarshal( URL xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The URI is {@link URI#toURL() turned into URL} and then
* follows the handling of URL.
*/
public static T unmarshal( URI xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The string is first interpreted as an absolute URI.
* If it's not {@link URI#isAbsolute() a valid absolute URI},
* then it's interpreted as a File
*/
public static T unmarshal( String xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The entire stream is read as an XML infoset.
* Upon a successful completion, the stream will be closed by this method.
*/
public static T unmarshal( InputStream xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The character stream is read as an XML infoset.
* The encoding declaration in the XML will be ignored.
* Upon a successful completion, the stream will be closed by this method.
*/
public static T unmarshal( Reader xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Reads in a Java object tree from the given XML input.
*
* @param xml
* The XML infoset that the {@link Source} represents is read.
*/
public static T unmarshal( Source xml, Class type ) {
try {
JAXBElement item = getContext(type).createUnmarshaller().unmarshal(toSource(xml), type);
return item.getValue();
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
/**
* Creates {@link Source} from various XML representation.
* See {@link #unmarshal} for the conversion rules.
*/
private static Source toSource(Object xml) throws IOException {
if(xml==null)
throw new IllegalArgumentException("no XML is given");
if (xml instanceof String) {
try {
xml=new URI((String)xml);
} catch (URISyntaxException e) {
xml=new File((String)xml);
}
}
if (xml instanceof File) {
File file = (File) xml;
return new StreamSource(file);
}
if (xml instanceof URI) {
URI uri = (URI) xml;
xml=uri.toURL();
}
if (xml instanceof URL) {
URL url = (URL) xml;
return new StreamSource(url.toExternalForm());
}
if (xml instanceof InputStream) {
InputStream in = (InputStream) xml;
return new StreamSource(in);
}
if (xml instanceof Reader) {
Reader r = (Reader) xml;
return new StreamSource(r);
}
if (xml instanceof Source) {
return (Source) xml;
}
throw new IllegalArgumentException("I don't understand how to handle "+xml.getClass());
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* XML will be written to this file. If it already exists,
* it will be overwritten.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, File xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The XML will be {@link URLConnection#getOutputStream() sent} to the
* resource pointed by this URL. Note that not all URLs support
* such operation, and exact semantics depends on the URL
* implementations. In case of {@link HttpURLConnection HTTP URLs},
* this will perform HTTP POST.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, URL xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The URI is {@link URI#toURL() turned into URL} and then
* follows the handling of URL. See above.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, URI xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The string is first interpreted as an absolute URI.
* If it's not {@link URI#isAbsolute() a valid absolute URI},
* then it's interpreted as a File
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, String xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The XML will be sent to the given {@link OutputStream}.
* Upon a successful completion, the stream will be closed by this method.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, OutputStream xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The XML will be sent as a character stream to the given {@link Writer}.
* Upon a successful completion, the stream will be closed by this method.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, Writer xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* The XML will be sent to the {@link Result} object.
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
public static void marshal( Object jaxbObject, Result xml ) {
_marshal(jaxbObject,xml);
}
/**
* Writes a Java object tree to XML and store it to the specified location.
*
*
* This method is a convenience method that combines several basic operations
* in the {@link JAXBContext} and {@link Marshaller}. This method is designed
* to be the prefered method for developers new to JAXB. This method
* has the following characterstics:
*
*
* - Generally speaking, the performance is not necessarily optimal.
* It is expected that those people who need to write performance
* critical code will use the rest of the JAXB API directly.
*
- Errors that happen during the processing is wrapped into
* {@link DataBindingException} (which will have {@link JAXBException}
* as its {@link Throwable#getCause() cause}. It is expected that
* those people who prefer the checked exception would use
* the rest of the JAXB API directly.
*
*
* @param jaxbObject
* The Java object to be marshalled into XML. If this object is
* a {@link JAXBElement}, it will provide the root tag name and
* the body. If this object has {@link XmlRootElement}
* on its class definition, that will be used as the root tag name
* and the given object will provide the body. Otherwise,
* the root tag name is {@link Introspector#decapitalize(String) infered} from
* {@link Class#getSimpleName() the short class name}.
* This parameter must not be null.
*
* @param xml
* Represents the receiver of XML. Objects of the following types are allowed.
*
*
* Type
* Operation
*
* {@link File}
* XML will be written to this file. If it already exists,
* it will be overwritten.
*
* {@link URL}
* The XML will be {@link URLConnection#getOutputStream() sent} to the
* resource pointed by this URL. Note that not all URLs support
* such operation, and exact semantics depends on the URL
* implementations. In case of {@link HttpURLConnection HTTP URLs},
* this will perform HTTP POST.
*
* {@link URI}
* The URI is {@link URI#toURL() turned into URL} and then
* follows the handling of URL. See above.
*
* {@link String}
* The string is first interpreted as an absolute URI.
* If it's not {@link URI#isAbsolute() a valid absolute URI},
* then it's interpreted as a File
*
* {@link OutputStream}
* The XML will be sent to the given {@link OutputStream}.
* Upon a successful completion, the stream will be closed by this method.
*
* {@link Writer}
* The XML will be sent as a character stream to the given {@link Writer}.
* Upon a successful completion, the stream will be closed by this method.
*
* {@link Result}
* The XML will be sent to the {@link Result} object.
*
*
* @throws DataBindingException
* If the operation fails, such as due to I/O error, unbindable classes.
*/
private static void _marshal( Object jaxbObject, Object xml ) {
try {
JAXBContext context;
if(jaxbObject instanceof JAXBElement) {
context = getContext(((JAXBElement)jaxbObject).getDeclaredType());
} else {
Class clazz = jaxbObject.getClass();
XmlRootElement r = clazz.getAnnotation(XmlRootElement.class);
context = getContext(clazz);
if(r==null) {
// we need to infer the name
jaxbObject = new JAXBElement(new QName(inferName(clazz)),clazz,jaxbObject);
}
}
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,true);
m.marshal(jaxbObject, toResult(xml));
} catch (JAXBException e) {
throw new DataBindingException(e);
} catch (IOException e) {
throw new DataBindingException(e);
}
}
private static String inferName(Class clazz) {
return Introspector.decapitalize(clazz.getSimpleName());
}
/**
* Creates {@link Result} from various XML representation.
* See {@link #_marshal(Object,Object)} for the conversion rules.
*/
private static Result toResult(Object xml) throws IOException {
if(xml==null)
throw new IllegalArgumentException("no XML is given");
if (xml instanceof String) {
try {
xml=new URI((String)xml);
} catch (URISyntaxException e) {
xml=new File((String)xml);
}
}
if (xml instanceof File) {
File file = (File) xml;
return new StreamResult(file);
}
if (xml instanceof URI) {
URI uri = (URI) xml;
xml=uri.toURL();
}
if (xml instanceof URL) {
URL url = (URL) xml;
URLConnection con = url.openConnection();
con.setDoOutput(true);
con.setDoInput(false);
con.connect();
return new StreamResult(con.getOutputStream());
}
if (xml instanceof OutputStream) {
OutputStream os = (OutputStream) xml;
return new StreamResult(os);
}
if (xml instanceof Writer) {
Writer w = (Writer)xml;
return new StreamResult(w);
}
if (xml instanceof Result) {
return (Result) xml;
}
throw new IllegalArgumentException("I don't understand how to handle "+xml.getClass());
}
}