/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.atlas.typesystem.types;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.google.common.collect.ImmutableSet;
/**
* Sorts hierarchical types by supertype dependency
*/
public class HierarchicalTypeDependencySorter {
/**
* Sorts the specified hierarchical types by supertype dependencies,
* such that any type A which is a supertype of type B
* will always be located earlier in the result list; that is, the supertype
* A would be found at some index i and subtype B would be found at some index j,
* and i < j.
*
* @param types hierarchical types to be sorted
* @return hierarchical types sorted by supertype dependency
*/
public static <T extends HierarchicalType> List<T> sortTypes(List<T> types) {
Map<String, T> typesByName = new HashMap<>();
for (T type : types) {
typesByName.put(type.name, type);
}
List<T> result = new ArrayList<>(types.size());
Set<T> processed = new HashSet<>();
for (T type : types) {
addToResult(type, result, processed, typesByName);
}
return result;
}
private static <T extends HierarchicalType> void addToResult(T type, List<T> result,
Set<T> processed, Map<String, T> typesByName) {
if (processed.contains(type)) {
return;
}
processed.add(type);
ImmutableSet<String> superTypeNames = type.superTypes;
for (String superTypeName : superTypeNames) {
// Recursively add any supertypes first to the result.
T superType = typesByName.get(superTypeName);
if (superType != null) {
addToResult(superType, result, processed, typesByName);
}
}
result.add(type);
}
}