org.springframework.context.index.CandidateComponentsIndex Maven / Gradle / Ivy
/*
* Copyright 2002-2020 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.context.index;
import java.util.Collections;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import java.util.stream.Collectors;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.ClassUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
/**
* Provide access to the candidates that are defined in {@code META-INF/spring.components}.
*
* An arbitrary number of stereotypes can be registered (and queried) on the index: a
* typical example is the fully qualified name of an annotation that flags the class for
* a certain use case. The following call returns all the {@code @Component}
* candidate types for the {@code com.example} package (and its sub-packages):
*
* Set<String> candidates = index.getCandidateTypes(
* "com.example", "org.springframework.stereotype.Component");
*
*
* The {@code type} is usually the fully qualified name of a class, though this is
* not a rule. Similarly, the {@code stereotype} is usually the fully qualified name of
* a target type but it can be any marker really.
*
* @author Stephane Nicoll
* @since 5.0
*/
public class CandidateComponentsIndex {
private static final AntPathMatcher pathMatcher = new AntPathMatcher(".");
private final MultiValueMap index;
CandidateComponentsIndex(List content) {
this.index = parseIndex(content);
}
private static MultiValueMap parseIndex(List content) {
MultiValueMap index = new LinkedMultiValueMap<>();
for (Properties entry : content) {
entry.forEach((type, values) -> {
String[] stereotypes = ((String) values).split(",");
for (String stereotype : stereotypes) {
index.add(stereotype, new Entry((String) type));
}
});
}
return index;
}
/**
* Return the candidate types that are associated with the specified stereotype.
* @param basePackage the package to check for candidates
* @param stereotype the stereotype to use
* @return the candidate types associated with the specified {@code stereotype}
* or an empty set if none has been found for the specified {@code basePackage}
*/
public Set getCandidateTypes(String basePackage, String stereotype) {
List candidates = this.index.get(stereotype);
if (candidates != null) {
return candidates.parallelStream()
.filter(t -> t.match(basePackage))
.map(t -> t.type)
.collect(Collectors.toSet());
}
return Collections.emptySet();
}
private static class Entry {
private final String type;
private final String packageName;
Entry(String type) {
this.type = type;
this.packageName = ClassUtils.getPackageName(type);
}
public boolean match(String basePackage) {
if (pathMatcher.isPattern(basePackage)) {
return pathMatcher.match(basePackage, this.packageName);
}
else {
return this.type.startsWith(basePackage);
}
}
}
}