spring-beans.dtd

spring的源代码

<?xml version="1.0" encoding="UTF-8"?>

<!--
	Spring XML BeanFactory DTD.
	Authors: Rod Johnson, Juergen Hoeller

	This defines a simple and consistent way of creating a namespace
	of JavaBeans configured by a Spring XmlBeanFactory.

	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.

	Bean instances can be "singletons" (shared instances) or "prototypes"
	(independent instances).

	References among beans are supported, i.e. setting a JavaBean property
	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 and names of such "inner beans" are always ignored:
	Inner beans are anonymous prototypes.

	There is also support for lists, maps, and java.util.Properties 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: spring-beans.dtd,v 1.25 2004/03/16 16:42:49 jhoeller 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)*
)>

<!--
	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>

<!--
	Each bean definition must specify the FQN of the class,
	or the name of the parent bean from which the class can be worked out.

	Note that a child bean definition that references a parent will just
	add respectively override property values and be able to change the
	singleton status. It will inherit all of the parent's other parameters
	like lazy initialization or autowire settings.
-->
<!ATTLIST bean class CDATA #IMPLIED>
<!ATTLIST bean parent 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>

<!--
	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".
-->
<!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>

<!--
	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>

<!--
	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,
	to be checked at runtime by future Spring 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 AbstractBeanFactory.
-->
<!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)
)>

<!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. The "key"
	attribute is the name of the property.
-->
<!ELEMENT prop
        (#PCDATA)
>

<!--
	Each property element must specify the key. The value is the
	element content: Note that whitespace is trimmed off to avoid
	unwanted whitespace caused by typical XML formatting.
-->
<!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 setting JavaBean
	properties to 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)>