/*
* Copyright 2002-2006 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
*
* http://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 {@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</code> for each
* logical entity being configured. Third parties can then {@link org.springframework.beans.factory.parsing.ReaderEventListener subscribe to these events},
* allowing for a user-centric view of the bean metadata.
*
* <p>Each <code>ComponentDefinition</code> 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</code> 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 org.springframework.beans.factory.parsing.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 ommitted. 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</code> 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 <code>ComponentDefinition</code>.
* <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.
* <p>Implementations are encouraged to return the same value from
* <code>toString()</code>.
*/
String getDescription();
/**
* Return the {@link BeanDefinition BeanDefinitions} that were registered
* to form this <code>ComponentDefinition</code>.
* <p>It should be noted that a <code>ComponentDefinition</code> 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 {@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 {@link BeanReference BeanReferences} that are considered
* to be important to this <code>ComponentDefinition</code>.
* <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();
}
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