| package org.eclipse.aether.util.graph.transformer; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| import org.eclipse.aether.RepositoryException; |
| import org.eclipse.aether.collection.UnsolvableVersionConflictException; |
| import org.eclipse.aether.graph.DependencyFilter; |
| import org.eclipse.aether.graph.DependencyNode; |
| import org.eclipse.aether.util.graph.transformer.ConflictResolver.ConflictContext; |
| import org.eclipse.aether.util.graph.transformer.ConflictResolver.ConflictItem; |
| import org.eclipse.aether.util.graph.transformer.ConflictResolver.VersionSelector; |
| import org.eclipse.aether.util.graph.visitor.PathRecordingDependencyVisitor; |
| import org.eclipse.aether.version.Version; |
| import org.eclipse.aether.version.VersionConstraint; |
| |
| /** |
| * A version selector for use with {@link ConflictResolver} that resolves version conflicts using a nearest-wins |
| * strategy. If there is no single node that satisfies all encountered version ranges, the selector will fail. |
| */ |
| public final class NearestVersionSelector |
| extends VersionSelector |
| { |
| |
| /** |
| * Creates a new instance of this version selector. |
| */ |
| public NearestVersionSelector() |
| { |
| } |
| |
| @Override |
| public void selectVersion( ConflictContext context ) |
| throws RepositoryException |
| { |
| ConflictGroup group = new ConflictGroup(); |
| for ( ConflictItem item : context.getItems() ) |
| { |
| DependencyNode node = item.getNode(); |
| VersionConstraint constraint = node.getVersionConstraint(); |
| |
| boolean backtrack = false; |
| boolean hardConstraint = constraint.getRange() != null; |
| |
| if ( hardConstraint ) |
| { |
| if ( group.constraints.add( constraint ) ) |
| { |
| if ( group.winner != null && !constraint.containsVersion( group.winner.getNode().getVersion() ) ) |
| { |
| backtrack = true; |
| } |
| } |
| } |
| |
| if ( isAcceptable( group, node.getVersion() ) ) |
| { |
| group.candidates.add( item ); |
| |
| if ( backtrack ) |
| { |
| backtrack( group, context ); |
| } |
| else if ( group.winner == null || isNearer( item, group.winner ) ) |
| { |
| group.winner = item; |
| } |
| } |
| else if ( backtrack ) |
| { |
| backtrack( group, context ); |
| } |
| } |
| context.setWinner( group.winner ); |
| } |
| |
| private void backtrack( ConflictGroup group, ConflictContext context ) |
| throws UnsolvableVersionConflictException |
| { |
| group.winner = null; |
| |
| for ( Iterator<ConflictItem> it = group.candidates.iterator(); it.hasNext(); ) |
| { |
| ConflictItem candidate = it.next(); |
| |
| if ( !isAcceptable( group, candidate.getNode().getVersion() ) ) |
| { |
| it.remove(); |
| } |
| else if ( group.winner == null || isNearer( candidate, group.winner ) ) |
| { |
| group.winner = candidate; |
| } |
| } |
| |
| if ( group.winner == null ) |
| { |
| throw newFailure( context ); |
| } |
| } |
| |
| private boolean isAcceptable( ConflictGroup group, Version version ) |
| { |
| for ( VersionConstraint constraint : group.constraints ) |
| { |
| if ( !constraint.containsVersion( version ) ) |
| { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| private boolean isNearer( ConflictItem item1, ConflictItem item2 ) |
| { |
| if ( item1.isSibling( item2 ) ) |
| { |
| return item1.getNode().getVersion().compareTo( item2.getNode().getVersion() ) > 0; |
| } |
| else |
| { |
| return item1.getDepth() < item2.getDepth(); |
| } |
| } |
| |
| private UnsolvableVersionConflictException newFailure( final ConflictContext context ) |
| { |
| DependencyFilter filter = new DependencyFilter() |
| { |
| public boolean accept( DependencyNode node, List<DependencyNode> parents ) |
| { |
| return context.isIncluded( node ); |
| } |
| }; |
| PathRecordingDependencyVisitor visitor = new PathRecordingDependencyVisitor( filter ); |
| context.getRoot().accept( visitor ); |
| return new UnsolvableVersionConflictException( visitor.getPaths() ); |
| } |
| |
| static final class ConflictGroup |
| { |
| |
| final Collection<VersionConstraint> constraints; |
| |
| final Collection<ConflictItem> candidates; |
| |
| ConflictItem winner; |
| |
| ConflictGroup() |
| { |
| constraints = new HashSet<>(); |
| candidates = new ArrayList<>( 64 ); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return String.valueOf( winner ); |
| } |
| |
| } |
| |
| } |