/**
* 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.ambari.tools.zk;
import static java.util.Collections.singletonList;
import static org.apache.ambari.tools.zk.ZkAcl.append;
import java.nio.file.FileSystems;
import java.nio.file.PathMatcher;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooKeeper;
/**
* Represents a Zookeeper path where each '/' separated segment might contain wildcard mask (*)
* E.g.: /ab/c/*//def
*/
public class ZkPathPattern {
private final List<Segment> segments;
/**
* Creates a instance from a pattern like /*//abc*
*/
public static ZkPathPattern fromString(String pattern) {
pattern = pattern.trim();
if (!pattern.startsWith("/")) {
throw new IllegalArgumentException("ZkPath must start with: '/'. Invalid path: " + pattern);
}
if ("/".equals(pattern)) {
return new ZkPathPattern(singletonList(new Segment("*")));
}
List<Segment> segments = new ArrayList<>();
for (String segment : pattern.substring(1).split("/")) {
if (segment.isEmpty()) {
throw new IllegalArgumentException("Invalid ZkPath: " + pattern);
}
segments.add(new Segment(segment));
}
if (segments.isEmpty()) {
throw new IllegalArgumentException("Empty ZkPath: " + pattern);
}
return new ZkPathPattern(segments);
}
private ZkPathPattern(List<Segment> segments) {
this.segments = segments;
}
/**
* Finds matching paths from the given base node
* E.g.:
* If the pattern is /*//abc* it will find nodes like:
* /a/abcdef
* /xy/abc/efg
* /def/abc
*/
public List<String> findMatchingPaths(ZooKeeper zkClient, String basePath) throws KeeperException, InterruptedException {
List<String> result = new ArrayList<>();
collectMatching(zkClient, basePath, result);
return result;
}
private void collectMatching(ZooKeeper zkClient, String basePath, List<String> result) throws KeeperException, InterruptedException {
for (String child : zkClient.getChildren(basePath, null)) {
if (first().matches(child)) {
if (rest() == null) {
result.add(append(basePath, child));
} else {
rest().collectMatching(zkClient, append(basePath, child), result);
}
}
}
}
private Segment first() {
return segments.get(0);
}
private ZkPathPattern rest() {
List<Segment> tail = segments.subList(1, segments.size());
return tail.isEmpty() ? null : new ZkPathPattern(tail);
}
public static class Segment {
private final PathMatcher glob;
public Segment(String segment) {
this.glob = FileSystems.getDefault().getPathMatcher("glob:" + segment);
}
public boolean matches(String node) {
return glob.matches(Paths.get(node));
}
}
}