/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.beans.factory.parsing;
import org.springframework.beans.BeanMetadataElement;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanReference;
Interface that describes the logical view of a set of BeanDefinitions and BeanReferences as presented in some configuration context. With the introduction of pluggable custom XML tags, it is now possible for a single logical configuration entity, in this case an XML tag, to create multiple BeanDefinitions and RuntimeBeanReferences in order to provide more succinct configuration and greater convenience to end users. As such, it can no longer be assumed that each configuration entity (e.g. XML tag) maps to one BeanDefinition. For tool vendors and other users who wish to present visualization or support for configuring Spring applications it is important that there is some mechanism in place to tie the BeanDefinitions in the BeanFactory back to the configuration data in a way that has concrete meaning to the end user. As such, NamespaceHandler implementations are able to publish events in the form of a ComponentDefinition for each logical entity being configured. Third parties can then subscribe to these events, allowing for a user-centric view of the bean metadata.
Each ComponentDefinition has a source object which is configuration-specific. In the case of XML-based configuration this is typically the Node which contains the user supplied configuration information. In addition to this, each BeanDefinition enclosed in a ComponentDefinition has its own source object which may point to a different, more specific, set of configuration data. Beyond this, individual pieces of bean metadata such as the PropertyValues may also have a source object giving an even greater level of detail. Source object extraction is handled through the SourceExtractor which can be customized as required.
Whilst direct access to important BeanReferences is provided through getBeanReferences, tools may wish to inspect all BeanDefinitions to gather the full set of BeanReferences. Implementations are required to provide all BeanReferences that are required to validate the configuration of the overall logical entity as well as those required to provide full user visualisation of the configuration. It is expected that certain BeanReferences will not be important to validation or to the user view of the configuration and as such these may be omitted. A tool may wish to display any additional BeanReferences sourced through the supplied BeanDefinitions but this is not considered to be a typical case.
Tools can determine the important of contained BeanDefinitions by checking the role identifier. The role is essentially a hint to the tool as to how important the configuration provider believes a BeanDefinition is to the end user. It is expected that tools will not display all BeanDefinitions for a given ComponentDefinition choosing instead to filter based on the role. Tools may choose to make this filtering user configurable. Particular notice should be given to the INFRASTRUCTURE role identifier. BeanDefinitions classified with this role are completely unimportant to the end user and are required only for internal implementation reasons.
Author: Rob Harrop, Juergen Hoeller See Also: Since: 2.0
/**
* Interface that describes the logical view of a set of {@link BeanDefinition BeanDefinitions}
* and {@link BeanReference BeanReferences} as presented in some configuration context.
*
* <p>With the introduction of {@link org.springframework.beans.factory.xml.NamespaceHandler pluggable custom XML tags},
* it is now possible for a single logical configuration entity, in this case an XML tag, to
* create multiple {@link BeanDefinition BeanDefinitions} and {@link BeanReference RuntimeBeanReferences}
* in order to provide more succinct configuration and greater convenience to end users. As such, it can
* no longer be assumed that each configuration entity (e.g. XML tag) maps to one {@link BeanDefinition}.
* For tool vendors and other users who wish to present visualization or support for configuring Spring
* applications it is important that there is some mechanism in place to tie the {@link BeanDefinition BeanDefinitions}
* in the {@link org.springframework.beans.factory.BeanFactory} back to the configuration data in a way
* that has concrete meaning to the end user. As such, {@link org.springframework.beans.factory.xml.NamespaceHandler}
* implementations are able to publish events in the form of a {@code ComponentDefinition} for each
* logical entity being configured. Third parties can then {@link ReaderEventListener subscribe to these events},
* allowing for a user-centric view of the bean metadata.
*
* <p>Each {@code ComponentDefinition} has a {@link #getSource source object} which is configuration-specific.
* In the case of XML-based configuration this is typically the {@link org.w3c.dom.Node} which contains the user
* supplied configuration information. In addition to this, each {@link BeanDefinition} enclosed in a
* {@code ComponentDefinition} has its own {@link BeanDefinition#getSource() source object} which may point
* to a different, more specific, set of configuration data. Beyond this, individual pieces of bean metadata such
* as the {@link org.springframework.beans.PropertyValue PropertyValues} may also have a source object giving an
* even greater level of detail. Source object extraction is handled through the
* {@link SourceExtractor} which can be customized as required.
*
* <p>Whilst direct access to important {@link BeanReference BeanReferences} is provided through
* {@link #getBeanReferences}, tools may wish to inspect all {@link BeanDefinition BeanDefinitions} to gather
* the full set of {@link BeanReference BeanReferences}. Implementations are required to provide
* all {@link BeanReference BeanReferences} that are required to validate the configuration of the
* overall logical entity as well as those required to provide full user visualisation of the configuration.
* It is expected that certain {@link BeanReference BeanReferences} will not be important to
* validation or to the user view of the configuration and as such these may be omitted. A tool may wish to
* display any additional {@link BeanReference BeanReferences} sourced through the supplied
* {@link BeanDefinition BeanDefinitions} but this is not considered to be a typical case.
*
* <p>Tools can determine the important of contained {@link BeanDefinition BeanDefinitions} by checking the
* {@link BeanDefinition#getRole role identifier}. The role is essentially a hint to the tool as to how
* important the configuration provider believes a {@link BeanDefinition} is to the end user. It is expected
* that tools will <strong>not</strong> display all {@link BeanDefinition BeanDefinitions} for a given
* {@code ComponentDefinition} choosing instead to filter based on the role. Tools may choose to make
* this filtering user configurable. Particular notice should be given to the
* {@link BeanDefinition#ROLE_INFRASTRUCTURE INFRASTRUCTURE role identifier}. {@link BeanDefinition BeanDefinitions}
* classified with this role are completely unimportant to the end user and are required only for
* internal implementation reasons.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
* @see AbstractComponentDefinition
* @see CompositeComponentDefinition
* @see BeanComponentDefinition
* @see ReaderEventListener#componentRegistered(ComponentDefinition)
*/
public interface ComponentDefinition extends BeanMetadataElement {
Get the user-visible name of this ComponentDefinition. This should link back directly to the corresponding configuration data
for this component in a given context.
/**
* Get the user-visible name of this {@code ComponentDefinition}.
* <p>This should link back directly to the corresponding configuration data
* for this component in a given context.
*/
String getName();
Return a friendly description of the described component.
Implementations are encouraged to return the same value from toString().
/**
* Return a friendly description of the described component.
* <p>Implementations are encouraged to return the same value from
* {@code toString()}.
*/
String getDescription();
Return the BeanDefinitions that were registered to form this ComponentDefinition. It should be noted that a ComponentDefinition may well be related with other BeanDefinitions via references, however these are not included as they may be not available immediately. Important BeanReferences are available from getBeanReferences().
Returns: the array of BeanDefinitions, or an empty array if none
/**
* Return the {@link BeanDefinition BeanDefinitions} that were registered
* to form this {@code ComponentDefinition}.
* <p>It should be noted that a {@code ComponentDefinition} may well be related with
* other {@link BeanDefinition BeanDefinitions} via {@link BeanReference references},
* however these are <strong>not</strong> included as they may be not available immediately.
* Important {@link BeanReference BeanReferences} are available from {@link #getBeanReferences()}.
* @return the array of BeanDefinitions, or an empty array if none
*/
BeanDefinition[] getBeanDefinitions();
Return the BeanDefinitions that represent all relevant inner beans within this component. Other inner beans may exist within the associated BeanDefinitions, however these are not considered to be needed for validation or for user visualization.
Returns: the array of BeanDefinitions, or an empty array if none
/**
* Return the {@link BeanDefinition BeanDefinitions} that represent all relevant
* inner beans within this component.
* <p>Other inner beans may exist within the associated {@link BeanDefinition BeanDefinitions},
* however these are not considered to be needed for validation or for user visualization.
* @return the array of BeanDefinitions, or an empty array if none
*/
BeanDefinition[] getInnerBeanDefinitions();
Return the set of BeanReferences that are considered to be important to this ComponentDefinition. Other BeanReferences may exist within the associated BeanDefinitions, however these are not considered to be needed for validation or for user visualization.
Returns: the array of BeanReferences, or an empty array if none
/**
* Return the set of {@link BeanReference BeanReferences} that are considered
* to be important to this {@code ComponentDefinition}.
* <p>Other {@link BeanReference BeanReferences} may exist within the associated
* {@link BeanDefinition BeanDefinitions}, however these are not considered
* to be needed for validation or for user visualization.
* @return the array of BeanReferences, or an empty array if none
*/
BeanReference[] getBeanReferences();
}