org.springframework.boot.context.properties.source.SpringConfigurationPropertySources Maven / Gradle / Ivy
/*
* Copyright 2012-2020 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.boot.context.properties.source;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.function.Function;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.PropertySource.StubPropertySource;
import org.springframework.util.Assert;
import org.springframework.util.ConcurrentReferenceHashMap;
import org.springframework.util.ConcurrentReferenceHashMap.ReferenceType;
/**
* Adapter to convert Spring's {@link MutablePropertySources} to
* {@link ConfigurationPropertySource ConfigurationPropertySources}.
*
* @author Phillip Webb
*/
class SpringConfigurationPropertySources implements Iterable {
private final Iterable> sources;
private final Map, ConfigurationPropertySource> cache = new ConcurrentReferenceHashMap<>(16,
ReferenceType.SOFT);
SpringConfigurationPropertySources(Iterable> sources) {
Assert.notNull(sources, "Sources must not be null");
this.sources = sources;
}
@Override
public Iterator iterator() {
return new SourcesIterator(this.sources.iterator(), this::adapt);
}
private ConfigurationPropertySource adapt(PropertySource source) {
ConfigurationPropertySource result = this.cache.get(source);
// Most PropertySources test equality only using the source name, so we need to
// check the actual source hasn't also changed.
if (result != null && result.getUnderlyingSource() == source) {
return result;
}
result = SpringConfigurationPropertySource.from(source);
this.cache.put(source, result);
return result;
}
private static class SourcesIterator implements Iterator {
private final Deque>> iterators;
private ConfigurationPropertySource next;
private final Function, ConfigurationPropertySource> adapter;
SourcesIterator(Iterator> iterator,
Function, ConfigurationPropertySource> adapter) {
this.iterators = new ArrayDeque<>(4);
this.iterators.push(iterator);
this.adapter = adapter;
}
@Override
public boolean hasNext() {
return fetchNext() != null;
}
@Override
public ConfigurationPropertySource next() {
ConfigurationPropertySource next = fetchNext();
if (next == null) {
throw new NoSuchElementException();
}
this.next = null;
return next;
}
private ConfigurationPropertySource fetchNext() {
if (this.next == null) {
if (this.iterators.isEmpty()) {
return null;
}
if (!this.iterators.peek().hasNext()) {
this.iterators.pop();
return fetchNext();
}
PropertySource candidate = this.iterators.peek().next();
if (candidate.getSource() instanceof ConfigurableEnvironment) {
push((ConfigurableEnvironment) candidate.getSource());
return fetchNext();
}
if (isIgnored(candidate)) {
return fetchNext();
}
this.next = this.adapter.apply(candidate);
}
return this.next;
}
private void push(ConfigurableEnvironment environment) {
this.iterators.push(environment.getPropertySources().iterator());
}
private boolean isIgnored(PropertySource candidate) {
return (candidate instanceof StubPropertySource
|| candidate instanceof ConfigurationPropertySourcesPropertySource);
}
}
}