org.eclipse.aether.util.graph.visitor.PathRecordingDependencyVisitor Maven / Gradle / Ivy
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.eclipse.aether.util.graph.visitor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.eclipse.aether.graph.DependencyFilter;
import org.eclipse.aether.graph.DependencyNode;
import org.eclipse.aether.graph.DependencyVisitor;
/**
* A dependency visitor that records all paths leading to nodes matching a certain filter criteria.
*/
public final class PathRecordingDependencyVisitor implements DependencyVisitor {
private final DependencyFilter filter;
private final List> paths;
private final Stack parents;
private final boolean excludeChildrenOfMatches;
/**
* Creates a new visitor that uses the specified filter to identify terminal nodes of interesting paths. The visitor
* will not search for paths going beyond an already matched node.
*
* @param filter The filter used to select terminal nodes of paths to record, may be {@code null} to match any node.
*/
public PathRecordingDependencyVisitor(DependencyFilter filter) {
this(filter, true);
}
/**
* Creates a new visitor that uses the specified filter to identify terminal nodes of interesting paths.
*
* @param filter The filter used to select terminal nodes of paths to record, may be {@code null} to match any node.
* @param excludeChildrenOfMatches Flag controlling whether children of matched nodes should be excluded from the
* traversal, thereby ignoring any potential paths to other matching nodes beneath a matching ancestor
* node. If {@code true}, all recorded paths will have only one matching node (namely the terminal node),
* if {@code false} a recorded path can consist of multiple matching nodes.
*/
public PathRecordingDependencyVisitor(DependencyFilter filter, boolean excludeChildrenOfMatches) {
this.filter = filter;
this.excludeChildrenOfMatches = excludeChildrenOfMatches;
paths = new ArrayList<>();
parents = new Stack<>();
}
/**
* Gets the filter being used to select terminal nodes.
*
* @return The filter being used or {@code null} if none.
*/
public DependencyFilter getFilter() {
return filter;
}
/**
* Gets the paths leading to nodes matching the filter that have been recorded during the graph visit. A path is
* given as a sequence of nodes, starting with the root node of the graph and ending with a node that matched the
* filter.
*
* @return The recorded paths, never {@code null}.
*/
public List> getPaths() {
return paths;
}
@Override
public boolean visitEnter(DependencyNode node) {
boolean accept = filter == null || filter.accept(node, parents);
boolean hasDuplicateNodeInParent = parents.contains(node);
parents.push(node);
if (accept) {
DependencyNode[] path = new DependencyNode[parents.size()];
for (int i = 0, n = parents.size(); i < n; i++) {
path[n - i - 1] = parents.get(i);
}
paths.add(Arrays.asList(path));
if (excludeChildrenOfMatches) {
return false;
}
}
return !hasDuplicateNodeInParent;
}
@Override
public boolean visitLeave(DependencyNode node) {
parents.pop();
return true;
}
}