/*
 * 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.List;
import java.util.function.BiPredicate;

import org.springframework.core.env.EnumerablePropertySource;
import org.springframework.core.env.PropertySource;

Strategy used to provide a mapping between a PropertySource and a ConfigurationPropertySource. 
 Mappings should be provided for both 
ConfigurationPropertyName types and String based names. This allows the SpringConfigurationPropertySource to first attempt any direct mappings (i.e. map the ConfigurationPropertyName directly to the PropertySource name) before falling back to enumerating property names, mapping them to a ConfigurationPropertyName and checking for applicability. See SpringConfigurationPropertySource for more details. 
Author:
Phillip Webb, Madhura Bhave
See Also:
SpringConfigurationPropertySource/**
 * Strategy used to provide a mapping between a {@link PropertySource} and a
 * {@link ConfigurationPropertySource}.
 * <p>
 * Mappings should be provided for both {@link ConfigurationPropertyName
 * ConfigurationPropertyName} types and {@code String} based names. This allows the
 * {@link SpringConfigurationPropertySource} to first attempt any direct mappings (i.e.
 * map the {@link ConfigurationPropertyName} directly to the {@link PropertySource} name)
 * before falling back to {@link EnumerablePropertySource enumerating} property names,
 * mapping them to a {@link ConfigurationPropertyName} and checking for applicability. See
 * {@link SpringConfigurationPropertySource} for more details.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 * @see SpringConfigurationPropertySource
 */
interface PropertyMapper {

	
The default ancestor of check.
/**
	 * The default ancestor of check.
	 */
	BiPredicate<ConfigurationPropertyName, ConfigurationPropertyName> DEFAULT_ANCESTOR_OF_CHECK = ConfigurationPropertyName::isAncestorOf;

	
Provide mappings from a ConfigurationPropertySource ConfigurationPropertyName. 
Params:
configurationPropertyName – the name to map
Returns:
the mapped names or an empty list/**
	 * Provide mappings from a {@link ConfigurationPropertySource}
	 * {@link ConfigurationPropertyName}.
	 * @param configurationPropertyName the name to map
	 * @return the mapped names or an empty list
	 */
	List<String> map(ConfigurationPropertyName configurationPropertyName);

	
Provide mappings from a PropertySource property name. 
Params:
propertySourceName – the name to map
Returns:
the mapped configuration property name or ConfigurationPropertyName.EMPTY/**
	 * Provide mappings from a {@link PropertySource} property name.
	 * @param propertySourceName the name to map
	 * @return the mapped configuration property name or
	 * {@link ConfigurationPropertyName#EMPTY}
	 */
	ConfigurationPropertyName map(String propertySourceName);

	
Returns a BiPredicate that can be used to check if one name is an ancestor of another when considering the mapping rules. 
Returns:
a predicate that can be used to check if one name is an ancestor of another/**
	 * Returns a {@link BiPredicate} that can be used to check if one name is an ancestor
	 * of another when considering the mapping rules.
	 * @return a predicate that can be used to check if one name is an ancestor of another
	 */
	default BiPredicate<ConfigurationPropertyName, ConfigurationPropertyName> getAncestorOfCheck() {
		return DEFAULT_ANCESTOR_OF_CHECK;
	}

}