org.elasticsearch.common.path.PathTrie Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.path;
import java.util.HashMap;
import java.util.Map;
import static java.util.Collections.emptyMap;
import static java.util.Collections.unmodifiableMap;
public class PathTrie {
public interface Decoder {
String decode(String value);
}
private final Decoder decoder;
private final TrieNode root;
private T rootValue;
private static final String SEPARATOR = "/";
private static final String WILDCARD = "*";
public PathTrie(Decoder decoder) {
this.decoder = decoder;
root = new TrieNode(SEPARATOR, null, WILDCARD);
}
public class TrieNode {
private transient String key;
private transient T value;
private boolean isWildcard;
private final String wildcard;
private transient String namedWildcard;
private Map children;
public TrieNode(String key, T value, String wildcard) {
this.key = key;
this.wildcard = wildcard;
this.isWildcard = (key.equals(wildcard));
this.value = value;
this.children = emptyMap();
if (isNamedWildcard(key)) {
namedWildcard = key.substring(key.indexOf('{') + 1, key.indexOf('}'));
} else {
namedWildcard = null;
}
}
public void updateKeyWithNamedWildcard(String key) {
this.key = key;
namedWildcard = key.substring(key.indexOf('{') + 1, key.indexOf('}'));
}
public boolean isWildcard() {
return isWildcard;
}
public synchronized void addChild(TrieNode child) {
addInnerChild(child.key, child);
}
private void addInnerChild(String key, TrieNode child) {
Map newChildren = new HashMap<>(children);
newChildren.put(key, child);
children = unmodifiableMap(newChildren);
}
public TrieNode getChild(String key) {
return children.get(key);
}
public synchronized void insert(String[] path, int index, T value) {
if (index >= path.length)
return;
String token = path[index];
String key = token;
if (isNamedWildcard(token)) {
key = wildcard;
}
TrieNode node = children.get(key);
if (node == null) {
T nodeValue = index == path.length - 1 ? value : null;
node = new TrieNode(token, nodeValue, wildcard);
addInnerChild(key, node);
} else {
if (isNamedWildcard(token)) {
node.updateKeyWithNamedWildcard(token);
}
// in case the target(last) node already exist but without a value
// than the value should be updated.
if (index == (path.length - 1)) {
assert (node.value == null || node.value == value);
if (node.value == null) {
node.value = value;
}
}
}
node.insert(path, index + 1, value);
}
private boolean isNamedWildcard(String key) {
return key.indexOf('{') != -1 && key.indexOf('}') != -1;
}
private String namedWildcard() {
return namedWildcard;
}
private boolean isNamedWildcard() {
return namedWildcard != null;
}
public T retrieve(String[] path, int index, Map params) {
if (index >= path.length)
return null;
String token = path[index];
TrieNode node = children.get(token);
boolean usedWildcard;
if (node == null) {
node = children.get(wildcard);
if (node == null) {
return null;
}
usedWildcard = true;
} else {
// If we are at the end of the path, the current node does not have a value but there
// is a child wildcard node, use the child wildcard node
if (index + 1 == path.length && node.value == null && children.get(wildcard) != null) {
node = children.get(wildcard);
usedWildcard = true;
} else {
usedWildcard = token.equals(wildcard);
}
}
put(params, node, token);
if (index == (path.length - 1)) {
return node.value;
}
T res = node.retrieve(path, index + 1, params);
if (res == null && !usedWildcard) {
node = children.get(wildcard);
if (node != null) {
put(params, node, token);
res = node.retrieve(path, index + 1, params);
}
}
return res;
}
private void put(Map params, TrieNode node, String value) {
if (params != null && node.isNamedWildcard()) {
params.put(node.namedWildcard(), decoder.decode(value));
}
}
@Override
public String toString() {
return key;
}
}
public void insert(String path, T value) {
String[] strings = path.split(SEPARATOR);
if (strings.length == 0) {
rootValue = value;
return;
}
int index = 0;
// supports initial delimiter.
if (strings.length > 0 && strings[0].isEmpty()) {
index = 1;
}
root.insert(strings, index, value);
}
public T retrieve(String path) {
return retrieve(path, null);
}
public T retrieve(String path, Map params) {
if (path.length() == 0) {
return rootValue;
}
String[] strings = path.split(SEPARATOR);
if (strings.length == 0) {
return rootValue;
}
int index = 0;
// supports initial delimiter.
if (strings.length > 0 && strings[0].isEmpty()) {
index = 1;
}
return root.retrieve(strings, index, params);
}
}