| /* |
| * Copyright 2015 Open Networking Laboratory |
| * |
| * 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.onlab.jdvue; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Objects; |
| |
| import static com.google.common.base.MoreObjects.toStringHelper; |
| |
| /** |
| * Simple representation of a Java package dependency cycle. |
| */ |
| public class DependencyCycle { |
| |
| private final List<JavaPackage> cycle; |
| |
| /** |
| * Creates a normalized dependency cycle represented by the specified list |
| * of Java packages, which are expected to be given in order of dependency. |
| * List is assumed to be non-empty. |
| * |
| * @param cycle list of Java packages in the dependency cycle |
| * @param cause Java package that caused the cycle |
| */ |
| DependencyCycle(List<JavaPackage> cycle, JavaPackage cause) { |
| this.cycle = normalize(cycle, cause); |
| } |
| |
| /** |
| * Produces a normalized dependency cycle list. Normalization is performed |
| * by rotating the list so that the package with the least lexicographic |
| * name is at the start of the list. |
| * |
| * @param cycle list of Java packages in the dependency cycle |
| * @param cause Java package that caused the cycle |
| * @return normalized cycle |
| */ |
| private List<JavaPackage> normalize(List<JavaPackage> cycle, JavaPackage cause) { |
| int start = cycle.indexOf(cause); |
| List<JavaPackage> clone = new ArrayList<>(cycle.subList(start, cycle.size())); |
| int leastIndex = findIndexOfLeastName(clone); |
| Collections.rotate(clone, -leastIndex); |
| return Collections.unmodifiableList(clone); |
| } |
| |
| /** |
| * Returns the index of the Java package with the least name. |
| * |
| * @param cycle list of Java packages in the dependency cycle |
| * @return index of the least Java package name |
| */ |
| private int findIndexOfLeastName(List<JavaPackage> cycle) { |
| int leastIndex = 0; |
| String leastName = cycle.get(leastIndex).name(); |
| for (int i = 1, n = cycle.size(); i < n; i++) { |
| JavaPackage javaPackage = cycle.get(i); |
| if (leastName.compareTo(javaPackage.name()) > 0) { |
| leastIndex = i; |
| leastName = javaPackage.name(); |
| } |
| } |
| return leastIndex; |
| } |
| |
| /** |
| * Returns the normalized Java package dependency cycle |
| * |
| * @return list of packages in the dependency cycle |
| */ |
| public List<JavaPackage> getCycle() { |
| return cycle; |
| } |
| |
| /** |
| * Returns the dependency cycle in form of individual dependencies. |
| * |
| * @return list of dependencies forming the cycle |
| */ |
| public List<Dependency> getCycleSegments() { |
| List<Dependency> dependencies = new ArrayList<>(); |
| for (int i = 0, n = cycle.size(); i < n; i++) { |
| dependencies.add(new Dependency(cycle.get(i), cycle.get(i < n - 1 ? i + 1 : 0))); |
| } |
| return dependencies; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o instanceof DependencyCycle) { |
| DependencyCycle that = (DependencyCycle) o; |
| return Objects.equals(cycle, that.cycle); |
| } |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| return cycle.hashCode(); |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this).add("cycle", cycle).toString(); |
| } |
| |
| public String toShortString() { |
| StringBuilder sb = new StringBuilder("["); |
| for (JavaPackage javaPackage : cycle) { |
| sb.append(javaPackage.name()).append(", "); |
| } |
| if (sb.length() > 1) { |
| sb.delete(sb.length() - 2, sb.length()); |
| } |
| sb.append("]"); |
| return sb.toString(); |
| } |
| |
| } |