<?xml version="1.0" encoding="UTF-8"?>
<!--
Spring XML Beans DTD
Authors: Rod Johnson, Juergen Hoeller, Alef Arendsen, Colin Sampaleanu
This defines a simple and consistent way of creating a namespace
of JavaBeans objects, configured by a Spring BeanFactory, read by
a DefaultXmlBeanDefinitionReader.
This document type is used by most Spring functionality, including
web application contexts, which are based on bean factories.
Each "bean" element in this document defines a JavaBean.
Typically the bean class is specified, along with JavaBean properties
and/or constructor arguments.
Bean instances can be "singletons" (shared instances) or "prototypes"
(independent instances). Further scopes are supposed to be built on top
of the core BeanFactory infrastructure and are therefore not part of it.
References among beans are supported, i.e. setting a JavaBean property
or a constructor argument to refer to another bean in the same factory
(or an ancestor factory).
As alternative to bean references, "inner bean definitions" can be used.
Singleton flags of such inner bean definitions are effectively ignored:
Inner beans are typically anonymous prototypes.
There is also support for lists, sets, maps, and java.util.Properties
as bean property types respectively constructor argument types.
As the format is simple, a DTD is sufficient, and there's no need
for a schema at this point.
XML documents that conform to this DTD should declare the following doctype:
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
$Id: dtd.xml,v 1.3 2005/03/23 18:42:00 yanger1997 Exp $
-->
<!--
Element containing informative text describing the purpose of the enclosing
element. Always optional.
Used primarily for user documentation of XML bean definition documents.
-->
<!ELEMENT description (#PCDATA)>
<!--
The document root.
At least one bean definition is required.
-->
<!ELEMENT beans (
description?,
bean+
)>
<!--
Default values for all bean definitions. Can be overridden at
the "bean" level. See those attribute definitions for details.
-->
<!ATTLIST beans default-lazy-init (true | false) "false">
<!ATTLIST beans default-dependency-check (none | objects | simple | all) "none">
<!ATTLIST beans default-autowire (no | byName | byType | constructor | autodetect) "no">
<!--
Defines a single named bean.
-->
<!ELEMENT bean (
description?,
(constructor-arg | property)*,
(lookup-method)*,
(replaced-method)*
)>
<!--
Beans can be identified by an id, to enable reference checking.
There are constraints on a valid XML id: if you want to reference your bean
in Java code using a name that's illegal as an XML id, use the optional
"name" attribute. If neither given, the bean class name is used as id.
-->
<!ATTLIST bean id ID #IMPLIED>
<!--
Optional. Can be used to create one or more aliases illegal in an id.
Multiple aliases can be separated by any number of spaces or commas.
-->
<!ATTLIST bean name CDATA #IMPLIED>
<!--
Optionally specify a parent bean definition.
Will use the bean class of the parent if none specified, but can
also override it. In the latter case, the child bean class must be
compatible with the parent, i.e. accept the parent's property values
and constructor argument values, if any.
A child bean definition will inherit constructor argument values,
property values and method overrides from the parent, with the option
to add new values. If init method, destroy method and/or static factory
method are specified, they will override the corresponding parent settings.
The remaining settings will <i>always</i> be taken from the child definition:
depends on, autowire mode, dependency check, singleton, lazy init.
-->
<!ATTLIST bean parent CDATA #IMPLIED>
<!--
Each bean definition must specify the fully qualified name of the class,
except if it pure serves as parent for child bean definitions.
-->
<!ATTLIST bean class CDATA #IMPLIED>
<!--
Is this bean a "singleton" (one shared instance, which will
be returned by all calls to getBean() with the id),
or a "prototype" (independent instance resulting from each call to
getBean(). Default is singleton.
Singletons are most commonly used, and are ideal for multi-threaded
service objects.
-->
<!ATTLIST bean singleton (true | false) "true">
<!--
If this bean should be lazily initialized.
If false, it will get instantiated on startup by bean factories
that perform eager initialization of singletons.
-->
<!ATTLIST bean lazy-init (true | false | default) "default">
<!--
Optional attribute controlling whether to "autowire" bean properties.
This is an automagical process in which bean references don't need to be coded
explicitly in the XML bean definition file, but Spring works out dependencies.
There are 5 modes:
1. "no"
The traditional Spring default. No automagical wiring. Bean references
must be defined in the XML file via the <ref> element. We recommend this
in most cases as it makes documentation more explicit.
2. "byName"
Autowiring by property name. If a bean of class Cat exposes a dog property,
Spring will try to set this to the value of the bean "dog" in the current factory.
3. "byType"
Autowiring if there is exactly one bean of the property type in the bean factory.
If there is more than one, a fatal error is raised, and you can't use byType
autowiring for that bean. If there is none, nothing special happens - use
dependency-check="objects" to raise an error in that case.
4. "constructor"
Analogous to "byType" for constructor arguments. If there isn't exactly one bean
of the constructor argument type in the bean factory, a fatal error is raised.
5. "autodetect"
Chooses "constructor" or "byType" through introspection of the bean class.
If a default constructor is found, "byType" gets applied.
The latter two are similar to PicoContainer and make bean factories simple to
configure for small namespaces, but doesn't work as well as standard Spring
behaviour for bigger applications.
Note that explicit dependencies, i.e. "property" and "constructor-arg" elements,
always override autowiring. Autowire behaviour can be combined with dependency
checking, which will be performed after all autowiring has been completed.
-->
<!ATTLIST bean autowire (no | byName | byType | constructor | autodetect | default) "default">
<!--
Optional attribute controlling whether to check whether all this
beans dependencies, expressed in its properties, are satisfied.
Default is no dependency checking.
"simple" type dependency checking includes primitives and String
"object" includes collaborators (other beans in the factory)
"all" includes both types of dependency checking
-->
<!ATTLIST bean dependency-check (none | objects | simple | all | default) "default">
<!--
The names of the beans that this bean depends on being initialized.
The bean factory will guarantee that these beans get initialized before.
Note that dependencies are normally expressed through bean properties or
constructor arguments. This property should just be necessary for other kinds
of dependencies like statics (*ugh*) or database preparation on startup.
-->
<!ATTLIST bean depends-on CDATA #IMPLIED>
<!--
Optional attribute for the name of the custom initialization method
to invoke after setting bean properties. The method must have no arguments,
but may throw any exception.
-->
<!ATTLIST bean init-method CDATA #IMPLIED>
<!--
Optional attribute for the name of the custom destroy method to invoke
on bean factory shutdown. The method must have no arguments,
but may throw any exception. Note: Only invoked on singleton beans!
-->
<!ATTLIST bean destroy-method CDATA #IMPLIED>
<!--
Optional attribute specifying the name of a static factory method to use
to create this object. Use constructor-arg elements to specify arguments
to the factory method, if it takes arguments. Autowiring does not
apply to factory methods.
The factory method will be on the class specified by the "class" attribute
on this bean definition. Often this will be the same class as that of the
constructed object - for example, when the factory method is used as an
alternative to a constructor. However, it may be on a different class. In
that case, the created object will *not* be of the class specified in
the "class" attribute. This is analogous to FactoryBean behaviour.
The factory method can have any number of arguments. Autowiring is not supported.
Use indexed constructor-arg elements in conjunction with the factory-method
attribute.
Setter Injection can be used in conjunction with a factory method.
Method Injection cannot, as the factory method returns an instance, which
will be used when the container creates the bean.
-->
<!ATTLIST bean factory-method CDATA #IMPLIED>
<!--
Bean definitions can specify zero or more constructor arguments.
They correspond to either a specific index of the constructor argument list
or are supposed to be matched generically by type.
This is an alternative to "autowire constructor".
constructor-arg elements are also used in conjunction with the factory-method
element to construct beans using static factory methods.
-->
<!ELEMENT constructor-arg (
description?,
(bean | ref | idref | list | set | map | props | value | null)
)>
<!--
The constructor-arg tag can have an optional index attribute,
to specify the exact index in the constructor argument list. Only needed
to avoid ambiguities, e.g. in case of 2 arguments of the same type.
-->
<!ATTLIST constructor-arg index CDATA #IMPLIED>
<!--
The constructor-arg tag can have an optional type attribute,
to specify the exact type of the constructor argument. Only needed
to avoid ambiguities, e.g. in case of 2 single argument constructors
that can both be converted from a String.
-->
<!ATTLIST constructor-arg type CDATA #IMPLIED>
<!--
Bean definitions can have zero or more properties.
Property elements correspond to JavaBean setter methods exposed
by the bean classes. Spring supports primitives, references to other
beans in the same or related factories, lists, maps and properties.
-->
<!ELEMENT property (
description?,
(bean | ref | idref | list | set | map | props | value | null)
)>
<!--
The property name attribute is the name of the JavaBean property.
This follows JavaBean conventions: a name of "age" would correspond
to setAge()/optional getAge() methods.
-->
<!ATTLIST property name CDATA #REQUIRED>
<!--
A lookup method causes the IoC container to override the given method and return
the bean with the name given in the bean attribute. This is a form of Method Injection.
It's particularly useful as an alternative to implementing the BeanFactoryAware
interface, in order to be able to make getBean() calls for non-singleton instances
at runtime. In this case, Method Injection is a less invasive alternative.
-->
<!ELEMENT lookup-method EMPTY>
<!--
Name of a lookup method. This method should take no arguments.
-->
<!ATTLIST lookup-method name CDATA #IMPLIED>
<!--
Similar to the lookup method mechanism, the replaced-method element is used to control
IoC container method overriding: Method Injection. This mechanism allows the overriding
of a method with arbitrary code.
-->
<!ELEMENT replaced-method (
(arg-type)*
)>
<!--
Name of the method whose implementation should be replaced by the IoC container.
If this method is not overloaded, there's no need to use arg-type subelements.
If this method is overloaded, arg-type subelements must be used for all
override definitions for the method.
-->
<!ATTLIST replaced-method name CDATA #IMPLIED>
<!--
Bean name of an implementation of the MethodReplacer interface
in the current or ancestor factories. This may be a singleton or prototype
bean. If it's a prototype, a new instance will be used for each method replacement.
Singleton usage is the norm.
-->
<!ATTLIST replaced-method replacer CDATA #IMPLIED>
<!--
Subelement of replaced-method identifying an argument for a replaced method
in the event of method overloading.
-->
<!ELEMENT arg-type (#PCDATA)>
<!--
Specification of the type of an overloaded method argument as a String.
For convenenince, this may be a substring of the FQN. E.g. all the
following would match "java.lang.String":
- java.lang.String
- String
- Str
As the number of arguments will be checked also, this convenience can often
be used to save typing
-->
<!ATTLIST arg-type match CDATA #IMPLIED>
<!--
Name of the bean in the current or ancestor factories that the lookup method
should resolve to. Often this bean will be a prototype, in which case the
lookup method will return a distinct instance on every invocation. This
is useful for single-threaded objects.
-->
<!ATTLIST lookup-method bean CDATA #IMPLIED>
<!--
Defines a reference to another bean in this factory or an external
factory (parent or included factory).
-->
<!ELEMENT ref EMPTY>
<!--
References must specify a name of the target bean.
The "bean" attribute can reference any name from any bean in the context,
to be checked at runtime.
Local references, using the "local" attribute, have to use bean ids;
they can be checked by this DTD, thus should be preferred for references
within the same bean factory XML file.
-->
<!ATTLIST ref bean CDATA #IMPLIED>
<!ATTLIST ref local IDREF #IMPLIED>
<!ATTLIST ref parent CDATA #IMPLIED>
<!--
Defines a string property value, which must also be the id of another
bean in this factory or an external factory (parent or included factory).
While a regular 'value' element could instead be used for the same effect,
using idref in this case allows validation of local bean ids by the xml
parser, and name completion by helper tools.
-->
<!ELEMENT idref EMPTY>
<!--
ID refs must specify a name of the target bean.
The "bean" attribute can reference any name from any bean in the context,
potentially to be checked at runtime by bean factory implementations.
Local references, using the "local" attribute, have to use bean ids;
they can be checked by this DTD, thus should be preferred for references
within the same bean factory XML file.
-->
<!ATTLIST idref bean CDATA #IMPLIED>
<!ATTLIST idref local IDREF #IMPLIED>
<!--
A list can contain multiple inner bean, ref, collection, or value elements.
Java lists are untyped, pending generics support in Java 1.5,
although references will be strongly typed.
A list can also map to an array type. The necessary conversion
is automatically performed by the BeanFactory.
-->
<!ELEMENT list (
(bean | ref | idref | list | set | map | props | value | null)*
)>
<!--
A set can contain multiple inner bean, ref, collection, or value elements.
Java sets are untyped, pending generics support in Java 1.5,
although references will be strongly typed.
-->
<!ELEMENT set (
(bean | ref | idref | list | set | map | props | value | null)*
)>
<!--
A Spring map is a mapping from a string key to object.
Maps may be empty.
-->
<!ELEMENT map (
(entry)*
)>
<!--
A map entry can be an inner bean, ref, collection, or value.
The name of the property is given by the "key" attribute.
-->
<!ELEMENT entry (
(bean | ref | idref | list | set | map | props | value | null)
)>
<!--
Each map element must specify its key.
-->
<!ATTLIST entry key CDATA #REQUIRED>
<!--
Props elements differ from map elements in that values must be strings.
Props may be empty.
-->
<!ELEMENT props (
(prop)*
)>
<!--
Element content is the string value of the property.
Note that whitespace is trimmed off to avoid unwanted whitespace
caused by typical XML formatting.
-->
<!ELEMENT prop
(#PCDATA)
>
<!--
Each property element must specify its key.
-->
<!ATTLIST prop key CDATA #REQUIRED>
<!--
Contains a string representation of a property value.
The property may be a string, or may be converted to the
required type using the JavaBeans PropertyEditor
machinery. This makes it possible for application developers
to write custom PropertyEditor implementations that can
convert strings to objects.
Note that this is recommended for simple objects only.
Configure more complex objects by populating JavaBean
properties with references to other beans.
-->
<!ELEMENT value (#PCDATA)>
<!--
Denotes a Java null value. Necessary because an empty "value" tag
will resolve to an empty String, which will not be resolved to a
null value unless a special PropertyEditor does so.
-->
<!ELEMENT null (#PCDATA)>