javax.xml.bind.JAXBContext Maven / Gradle / Ivy
/*
* Copyright 2003 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.xml.bind;
import org.w3c.dom.Node;
import java.util.Collections;
import java.util.Map;
import java.util.Properties;
import java.io.IOException;
import java.io.InputStream;
/**
*
* The JAXBContext class provides the client's entry point to the
* JAXB API. It provides an abstraction for managing the XML/Java binding
* information necessary to implement the JAXB binding framework operations:
* unmarshal, marshal and validate.
*
*
A client application normally obtains new instances of this class using
* one of these two styles for newInstance methods, although there are other
* specialized forms of the method available:
*
*
* - {@link #newInstance(String,ClassLoader) JAXBContext.newInstance( "com.acme.foo:com.acme.bar" )}
* The JAXBContext instance is initialized from a list of colon
* separated Java package names. Each java package contains
* JAXB mapped classes, schema-derived classes and/or user annotated
* classes. Additionally, the java package may contain JAXB package annotations
* that must be processed. (see JLS 3rd Edition, Section 7.4.1. Package Annotations).
*
* - {@link #newInstance(Class...) JAXBContext.newInstance( com.acme.foo.Foo.class )}
* The JAXBContext instance is intialized with class(es)
* passed as parameter(s) and classes that are statically reachable from
* these class(es). See {@link #newInstance(Class...)} for details.
*
*
*
*
* SPEC REQUIREMENT: the provider must supply an implementation
* class containing the following method signatures:
*
*
* public static JAXBContext createContext( String contextPath, ClassLoader classLoader, Map properties ) throws JAXBException
* public static JAXBContext createContext( Class[] classes, Map properties ) throws JAXBException
*
*
*
* The following JAXB 1.0 requirement is only required for schema to
* java interface/implementation binding. It does not apply to JAXB annotated
* classes. JAXB Providers must generate a jaxb.properties file in
* each package containing schema derived classes. The property file must
* contain a property named javax.xml.bind.context.factory whose
* value is the name of the class that implements the createContext
* APIs.
*
*
* The class supplied by the provider does not have to be assignable to
* javax.xml.bind.JAXBContext, it simply has to provide a class that
* implements the createContext APIs.
*
*
* In addition, the provider must call the
* {@link DatatypeConverter#setDatatypeConverter(DatatypeConverterInterface)
* DatatypeConverter.setDatatypeConverter} api prior to any client
* invocations of the marshal and unmarshal methods. This is necessary to
* configure the datatype converter that will be used during these operations.
*
*
*
Unmarshalling
*
* The {@link Unmarshaller} class provides the client application the ability
* to convert XML data into a tree of Java content objects.
* The unmarshal method allows for
* any global XML element declared in the schema to be unmarshalled as
* the root of an instance document.
* Additionally, the unmarshal method allows for an unrecognized root element that
* has an xsi:type attribute's value that references a type definition declared in
* the schema to be unmarshalled as the root of an instance document.
* The JAXBContext object
* allows the merging of global elements and type definitions across a set of schemas (listed
* in the contextPath). Since each schema in the schema set can belong
* to distinct namespaces, the unification of schemas to an unmarshalling
* context should be namespace independent. This means that a client
* application is able to unmarshal XML documents that are instances of
* any of the schemas listed in the contextPath. For example:
*
*
* JAXBContext jc = JAXBContext.newInstance( "com.acme.foo:com.acme.bar" );
* Unmarshaller u = jc.createUnmarshaller();
* FooObject fooObj = (FooObject)u.unmarshal( new File( "foo.xml" ) ); // ok
* BarObject barObj = (BarObject)u.unmarshal( new File( "bar.xml" ) ); // ok
* BazObject bazObj = (BazObject)u.unmarshal( new File( "baz.xml" ) ); // error, "com.acme.baz" not in contextPath
*
*
*
* The client application may also generate Java content trees explicitly rather
* than unmarshalling existing XML data. For all JAXB-annotated value classes,
* an application can create content using constructors.
* For schema-derived interface/implementation classes and for the
* creation of elements that are not bound to a JAXB-annotated
* class, an application needs to have access and knowledge about each of
* the schema derived ObjectFactory classes that exist in each of
* java packages contained in the contextPath. For each schema
* derived java class, there is a static factory method that produces objects
* of that type. For example,
* assume that after compiling a schema, you have a package com.acme.foo
* that contains a schema derived interface named PurchaseOrder. In
* order to create objects of that type, the client application would use the
* factory method like this:
*
*
* com.acme.foo.PurchaseOrder po =
* com.acme.foo.ObjectFactory.createPurchaseOrder();
*
*
*
* Once the client application has an instance of the the schema derived object,
* it can use the mutator methods to set content on it.
*
*
* For more information on the generated ObjectFactory classes, see
* Section 4.2 Java Package of the specification.
*
*
* SPEC REQUIREMENT: the provider must generate a class in each
* package that contains all of the necessary object factory methods for that
* package named ObjectFactory as well as the static
* newInstance( javaContentInterface ) method
*
*
Marshalling
*
* The {@link Marshaller} class provides the client application the ability
* to convert a Java content tree back into XML data. There is no difference
* between marshalling a content tree that is created manually using the factory
* methods and marshalling a content tree that is the result an unmarshal
* operation. Clients can marshal a java content tree back to XML data
* to a java.io.OutputStream or a java.io.Writer. The
* marshalling process can alternatively produce SAX2 event streams to a
* registered ContentHandler or produce a DOM Node object.
* Client applications have control over the output encoding as well as
* whether or not to marshal the XML data as a complete document or
* as a fragment.
*
*
* Here is a simple example that unmarshals an XML document and then marshals
* it back out:
*
*
* JAXBContext jc = JAXBContext.newInstance( "com.acme.foo" );
*
* // unmarshal from foo.xml
* Unmarshaller u = jc.createUnmarshaller();
* FooObject fooObj = (FooObject)u.unmarshal( new File( "foo.xml" ) );
*
* // marshal to System.out
* Marshaller m = jc.createMarshaller();
* m.marshal( fooObj, System.out );
*
*
*
* Validation
*
* Validation has been changed significantly since JAXB 1.0. The {@link Validator}
* class has been deprecated and made optional. This means that you are advised
* not to use this class and, in fact, it may not even be available depending on
* your JAXB provider. JAXB 1.0 client applications that rely on Validator
* will still work properly when deployed with the JAXB 1.0 runtime system.
*
* In JAXB 2.0, the {@link Unmarshaller} has included convenince methods that expose
* the JAXP 1.3 {@link javax.xml.validation} framework. Please refer to the
* {@link Unmarshaller#setSchema(javax.xml.validation.Schema)} API for more
* information.
*
*
*
JAXB Runtime Binding Framework Compatibility
*
* The following JAXB 1.0 restriction only applies to binding schema to
* interfaces/implementation classes.
* Since this binding does not require a common runtime system, a JAXB
* client application must not attempt to mix runtime objects (JAXBContext,
* Marshaller, etc. ) from different providers. This does not
* mean that the client application isn't portable, it simply means that a
* client has to use a runtime system provided by the same provider that was
* used to compile the schema.
*
*
*
Discovery of JAXB implementation
*
* When one of the newInstance methods is called, a JAXB implementation is discovered
* by the following steps.
*
*
* -
* For each package/class explicitly passed in to the {@link #newInstance} method, in the order they are specified,
* jaxb.properties file is looked up in its package, by using the associated classloader —
* this is {@link Class#getClassLoader() the owner class loader} for a {@link Class} argument, and for a package
* the speified {@link ClassLoader}.
*
*
* If such a file is discovered, it is {@link Properties#load(InputStream) loaded} as a property file, and
* the value of the {@link #JAXB_CONTEXT_FACTORY} key will be assumed to be the provider factory class.
* This class is then loaded by the associated classloader discussed above.
*
*
* This phase of the look up allows some packages to force the use of a certain JAXB implementation.
* (For example, perhaps the schema compiler has generated some vendor extension in the code.)
*
*
-
* If the system property {@link #JAXB_CONTEXT_FACTORY} exists, then its value is assumed to be the provider
* factory class. This phase of the look up enables per-JVM override of the JAXB implementation.
*
*
-
* Look for /META-INF/services/javax.xml.bind.JAXBContext file in the associated classloader.
* This file follows the standard service descriptor convention, and if such a file exists, its content
* is assumed to be the provider factory class. This phase of the look up is for automatic discovery.
* It allows users to just put a JAXB implementation in a classpath and use it without any furhter configuration.
*
*
-
* Finally, if all the steps above fail, then the rest of the look up is unspecified. That said,
* the recommended behavior is to simply look for some hard-coded platform default JAXB implementation.
* This phase of the look up is so that JavaSE can have its own JAXB implementation as the last resort.
*
*
*
* Once the provider factory class is discovered, its
* public static JAXBContext createContext(String,ClassLoader,Map) method
* (see {@link #newInstance(String, ClassLoader, Map)} for the parameter semantics.)
* or public static JAXBContext createContet(Class[],Map) method
* (see {@link #newInstance(Class[], Map)} for the parameter semantics) are invoked
* to create a {@link JAXBContext}.
*
*
* @author - Ryan Shoemaker, Sun Microsystems, Inc.
- Kohsuke Kawaguchi, Sun Microsystems, Inc.
- Joe Fialli, Sun Microsystems, Inc.
* @see Marshaller
* @see Unmarshaller
* @see S 7.4.1.1 "Package Annotations" in Java Language Specification, 3rd Edition
* @since JAXB1.0
*/
public abstract class JAXBContext {
/**
* The name of the property that contains the name of the class capable
* of creating new JAXBContext objects.
*/
public static final String JAXB_CONTEXT_FACTORY =
"javax.xml.bind.context.factory";
protected JAXBContext() {
}
/**
*
* Obtain a new instance of a JAXBContext class.
*
*
* This is a convenience method to invoke the
* {@link #newInstance(String,ClassLoader)} method with
* the context class loader of the current thread.
*
* @throws JAXBException if an error was encountered while creating the
* JAXBContext such as
*
* - failure to locate either ObjectFactory.class or jaxb.index in the packages
* - an ambiguity among global elements contained in the contextPath
* - failure to locate a value for the context factory provider property
* - mixing schema derived packages from different providers on the same contextPath
*
*/
public static JAXBContext newInstance( String contextPath )
throws JAXBException {
//return newInstance( contextPath, JAXBContext.class.getClassLoader() );
return newInstance( contextPath, Thread.currentThread().getContextClassLoader() );
}
/**
*
* Obtain a new instance of a JAXBContext class.
*
*
* The client application must supply a context path which is a list of
* colon (':', \u005Cu003A) separated java package names that contain
* schema-derived classes and/or fully qualified JAXB-annotated classes.
* Schema-derived
* code is registered with the JAXBContext by the
* ObjectFactory.class generated per package.
* Alternatively than being listed in the context path, programmer
* annotated JAXB mapped classes can be listed in a
* jaxb.index resource file, format described below.
* Note that a java package can contain both schema-derived classes and
* user annotated JAXB classes. Additionally, the java package may
* contain JAXB package annotations that must be processed. (see JLS 3rd Edition,
* Section 7.4.1. "Package Annotations").
*
*
*
* Every package listed on the contextPath must meet one or both of the
* following conditions otherwise a JAXBException will be thrown:
*
*
* - it must contain ObjectFactory.class
* - it must contain jaxb.index
*
*
*
* Format for jaxb.index
*
* The file contains a newline-separated list of class names.
* Space and tab characters, as well as blank
* lines, are ignored. The comment character
* is '#' (0x23); on each line all characters following the first comment
* character are ignored. The file must be encoded in UTF-8. Classes that
* are reachable, as defined in {@link #newInstance(Class...)}, from the
* listed classes are also registered with JAXBContext.
*
* Constraints on class name occuring in a jaxb.index file are:
*
* - Must not end with ".class".
* - Class names are resolved relative to package containing
* jaxb.index file. Only classes occuring directly in package
* containing jaxb.index file are allowed.
* - Fully qualified class names are not allowed.
* A qualified class name,relative to current package,
* is only allowed to specify a nested or inner class.
*
*
*
* To maintain compatibility with JAXB 1.0 schema to java
* interface/implementation binding, enabled by schema customization
*
* If there are any global XML element name collisions across the various
* packages listed on the contextPath, a JAXBException
* will be thrown.
*
*
* Mixing generated interface/impl bindings from multiple JAXB Providers
* in the same context path may result in a JAXBException
* being thrown.
*
*
* The steps involved in discovering the JAXB implementation is discussed in the class javadoc.
*
* @param contextPath list of java package names that contain schema
* derived class and/or java to schema (JAXB-annotated)
* mapped classes
* @param classLoader
* This class loader will be used to locate the implementation
* classes.
*
* @return a new instance of a JAXBContext
* @throws JAXBException if an error was encountered while creating the
* JAXBContext such as
*
* - failure to locate either ObjectFactory.class or jaxb.index in the packages
* - an ambiguity among global elements contained in the contextPath
* - failure to locate a value for the context factory provider property
* - mixing schema derived packages from different providers on the same contextPath
*
*/
public static JAXBContext newInstance( String contextPath, ClassLoader classLoader ) throws JAXBException {
return newInstance(contextPath,classLoader,Collections.emptyMap());
}
/**
*
* Obtain a new instance of a JAXBContext class.
*
*
* This is mostly the same as {@link JAXBContext#newInstance(String, ClassLoader)},
* but this version allows you to pass in provider-specific properties to configure
* the instanciation of {@link JAXBContext}.
*
*
* The interpretation of properties is up to implementations. Implementations should
* throw JAXBException if it finds properties that it doesn't understand.
*
* @param contextPath list of java package names that contain schema derived classes
* @param classLoader
* This class loader will be used to locate the implementation classes.
* @param properties
* provider-specific properties. Can be null, which means the same thing as passing
* in an empty map.
*
* @return a new instance of a JAXBContext
* @throws JAXBException if an error was encountered while creating the
* JAXBContext such as
*
* - failure to locate either ObjectFactory.class or jaxb.index in the packages
* - an ambiguity among global elements contained in the contextPath
* - failure to locate a value for the context factory provider property
* - mixing schema derived packages from different providers on the same contextPath
*
* @since JAXB2.0
*/
public static JAXBContext newInstance( String contextPath, ClassLoader classLoader, Map properties )
throws JAXBException {
return ContextFinder.find(
/* The default property name according to the JAXB spec */
JAXB_CONTEXT_FACTORY,
/* the context path supplied by the client app */
contextPath,
/* class loader to be used */
classLoader,
properties );
}
// TODO: resurrect this once we introduce external annotations
// /**
// *
// * Obtain a new instance of a JAXBContext class.
// *
// *
// * The client application must supply a list of classes that the new
// * context object needs to recognize.
// *
// * Not only the new context will recognize all the classes specified,
// * but it will also recognize any classes that are directly/indirectly
// * referenced statically from the specified classes.
// *
// * For example, in the following Java code, if you do
// * newInstance(Foo.class), the newly created {@link JAXBContext}
// * will recognize both Foo and Bar, but not Zot:
// *
// * class Foo {
// * Bar b;
// * }
// * class Bar { int x; }
// * class Zot extends Bar { int y; }
// *
// *
// * Therefore, a typical client application only needs to specify the
// * top-level classes, but it needs to be careful.
// *
// * TODO: if we are to define other mechanisms, refer to them.
// *
// * @param externalBindings
// * list of external binding files. Can be null or empty if none is used.
// * when specified, those files determine how the classes are bound.
// *
// * @param classesToBeBound
// * list of java classes to be recognized by the new {@link JAXBContext}.
// * Can be empty, in which case a {@link JAXBContext} that only knows about
// * spec-defined classes will be returned.
// *
// * @return
// * A new instance of a JAXBContext. Always non-null valid object.
// *
// * @throws JAXBException
// * if an error was encountered while creating the
// * JAXBContext, such as (but not limited to):
// *
// * - No JAXB implementation was discovered
// *
- Classes use JAXB annotations incorrectly
// *
- Classes have colliding annotations (i.e., two classes with the same type name)
// *
- Specified external bindings are incorrect
// *
- The JAXB implementation was unable to locate
// * provider-specific out-of-band information (such as additional
// * files generated at the development time.)
// *
// *
// * @throws IllegalArgumentException
// * if the parameter contains {@code null} (i.e., {@code newInstance(null);})
// *
// * @since JAXB2.0
// */
// public static JAXBContext newInstance( Source[] externalBindings, Class... classesToBeBound )
// throws JAXBException {
//
// // empty class list is not an error, because the context will still include
// // spec-specified classes like String and Integer.
// // if(classesToBeBound.length==0)
// // throw new IllegalArgumentException();
//
// // but it is an error to have nulls in it.
// for( int i=classesToBeBound.length-1; i>=0; i-- )
// if(classesToBeBound[i]==null)
// throw new IllegalArgumentException();
//
// return ContextFinder.find(externalBindings,classesToBeBound);
// }
/**
*
* Obtain a new instance of a JAXBContext class.
*
*
* The client application must supply a list of classes that the new
* context object needs to recognize.
*
* Not only the new context will recognize all the classes specified,
* but it will also recognize any classes that are directly/indirectly
* referenced statically from the specified classes. Subclasses of
* referenced classes nor @XmlTransient referenced classes
* are not registered with JAXBContext.
*
* For example, in the following Java code, if you do
* newInstance(Foo.class), the newly created {@link JAXBContext}
* will recognize both Foo and Bar, but not Zot or FooBar:
*
* class Foo {
* @XmlTransient FooBar c;
* Bar b;
* }
* class Bar { int x; }
* class Zot extends Bar { int y; }
* class FooBar { }
*
*
* Therefore, a typical client application only needs to specify the
* top-level classes, but it needs to be careful.
*
*
* Note that for each java package registered with JAXBContext,
* when the optional package annotations exist, they must be processed.
* (see JLS 3rd Edition, Section 7.4.1. "Package Annotations").
*
*
* The steps involved in discovering the JAXB implementation is discussed in the class javadoc.
*
* @param classesToBeBound
* list of java classes to be recognized by the new {@link JAXBContext}.
* Can be empty, in which case a {@link JAXBContext} that only knows about
* spec-defined classes will be returned.
*
* @return
* A new instance of a JAXBContext. Always non-null valid object.
*
* @throws JAXBException
* if an error was encountered while creating the
* JAXBContext, such as (but not limited to):
*
* - No JAXB implementation was discovered
*
- Classes use JAXB annotations incorrectly
*
- Classes have colliding annotations (i.e., two classes with the same type name)
*
- The JAXB implementation was unable to locate
* provider-specific out-of-band information (such as additional
* files generated at the development time.)
*
*
* @throws IllegalArgumentException
* if the parameter contains {@code null} (i.e., {@code newInstance(null);})
*
* @since JAXB2.0
*/
public static JAXBContext newInstance( Class... classesToBeBound )
throws JAXBException {
return newInstance(classesToBeBound,Collections.emptyMap());
}
/**
*
* Obtain a new instance of a JAXBContext class.
*
*
* An overloading of {@link JAXBContext#newInstance(Class...)}
* to configure 'properties' for this instantiation of {@link JAXBContext}.
*
*
* The interpretation of properties is up to implementations. Implementations should
* throw JAXBException if it finds properties that it doesn't understand.
*
* @param classesToBeBound
* list of java classes to be recognized by the new {@link JAXBContext}.
* Can be empty, in which case a {@link JAXBContext} that only knows about
* spec-defined classes will be returned.
* @param properties
* provider-specific properties. Can be null, which means the same thing as passing
* in an empty map.
*
* @return
* A new instance of a JAXBContext. Always non-null valid object.
*
* @throws JAXBException
* if an error was encountered while creating the
* JAXBContext, such as (but not limited to):
*
* - No JAXB implementation was discovered
*
- Classes use JAXB annotations incorrectly
*
- Classes have colliding annotations (i.e., two classes with the same type name)
*
- The JAXB implementation was unable to locate
* provider-specific out-of-band information (such as additional
* files generated at the development time.)
*
*
* @throws IllegalArgumentException
* if the parameter contains {@code null} (i.e., {@code newInstance(null,someMap);})
*
* @since JAXB2.0
*/
public static JAXBContext newInstance( Class[] classesToBeBound, Map properties )
throws JAXBException {
if (classesToBeBound == null) throw new IllegalArgumentException();
// but it is an error to have nulls in it.
for( int i=classesToBeBound.length-1; i>=0; i-- )
if(classesToBeBound[i]==null)
throw new IllegalArgumentException();
return ContextFinder.find(classesToBeBound,properties);
}
/**
* Create an Unmarshaller object that can be used to convert XML
* data into a java content tree.
*
* @return an Unmarshaller object
*
* @throws JAXBException if an error was encountered while creating the
* Unmarshaller object
*/
public abstract Unmarshaller createUnmarshaller() throws JAXBException;
/**
* Create a Marshaller object that can be used to convert a
* java content tree into XML data.
*
* @return a Marshaller object
*
* @throws JAXBException if an error was encountered while creating the
* Marshaller object
*/
public abstract Marshaller createMarshaller() throws JAXBException;
/**
* {@link Validator} has been made optional and deprecated in JAXB 2.0. Please
* refer to the javadoc for {@link Validator} for more detail.
*
* Create a Validator object that can be used to validate a
* java content tree against its source schema.
*
* @return a Validator object
*
* @throws JAXBException if an error was encountered while creating the
* Validator object
* @deprecated since JAXB2.0
*/
public abstract Validator createValidator() throws JAXBException;
/**
* Creates a Binder object that can be used for
* associative/in-place unmarshalling/marshalling.
*
* @param domType select the DOM API to use by passing in its DOM Node class.
*
* @return always a new valid Binder object.
*
* @throws UnsupportedOperationException
* if DOM API corresponding to domType is not supported by
* the implementation.
*
* @since JAXB2.0
*/
public Binder createBinder(Class domType) {
// to make JAXB 1.0 implementations work, this method must not be
// abstract
throw new UnsupportedOperationException();
}
/**
* Creates a Binder for W3C DOM.
*
* @return always a new valid Binder object.
*
* @since JAXB2.0
*/
public Binder createBinder() {
return createBinder(Node.class);
}
/**
* Creates a JAXBIntrospector object that can be used to
* introspect JAXB objects.
*
* @return
* always return a non-null valid JAXBIntrospector object.
*
* @throws UnsupportedOperationException
* Calling this method on JAXB 1.0 implementations will throw
* an UnsupportedOperationException.
*
* @since JAXB2.0
*/
public JAXBIntrospector createJAXBIntrospector() {
// to make JAXB 1.0 implementations work, this method must not be
// abstract
throw new UnsupportedOperationException();
}
/**
* Generates the schema documents for this context.
*
* @param outputResolver
* this object controls the output to which schemas
* will be sent.
*
* @throws IOException
* if {@link SchemaOutputResolver} throws an {@link IOException}.
*
* @throws UnsupportedOperationException
* Calling this method on JAXB 1.0 implementations will throw
* an UnsupportedOperationException.
*
* @since JAXB 2.0
*/
public void generateSchema(SchemaOutputResolver outputResolver) throws IOException {
// to make JAXB 1.0 implementations work, this method must not be
// abstract
throw new UnsupportedOperationException();
}
}