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/*
* 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.index.mapper;
import org.elasticsearch.common.collect.CopyOnWriteHashMap;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
/**
* A container that supports looking up field types for 'dynamic key' fields ({@link DynamicKeyFieldMapper}).
*
* Compared to standard fields, 'dynamic key' fields require special handling. Given a field name of the form
* 'path_to_field.path_to_key', the container will dynamically return a new {@link MappedFieldType} that is
* suitable for performing searches on the sub-key.
*
* Note: we anticipate that 'flattened' fields will be the only implementation {@link DynamicKeyFieldMapper}.
* Flattened object fields live in the 'mapper-flattened' module.
*/
class DynamicKeyFieldTypeLookup {
private final CopyOnWriteHashMap mappers;
private final Map aliasToConcreteName;
/**
* The maximum field depth of any dynamic key mapper. Allows us to stop searching for
* a dynamic key mapper as soon as we've passed the maximum possible field depth.
*/
private final int maxKeyDepth;
DynamicKeyFieldTypeLookup() {
this.mappers = new CopyOnWriteHashMap<>();
this.aliasToConcreteName = Collections.emptyMap();
this.maxKeyDepth = 0;
}
private DynamicKeyFieldTypeLookup(CopyOnWriteHashMap mappers,
Map aliasToConcreteName,
int maxKeyDepth) {
this.mappers = mappers;
this.aliasToConcreteName = aliasToConcreteName;
this.maxKeyDepth = maxKeyDepth;
}
DynamicKeyFieldTypeLookup copyAndAddAll(Map newMappers,
Map aliasToConcreteName) {
CopyOnWriteHashMap combinedMappers = this.mappers.copyAndPutAll(newMappers);
int maxKeyDepth = getMaxKeyDepth(combinedMappers, aliasToConcreteName);
return new DynamicKeyFieldTypeLookup(combinedMappers, aliasToConcreteName, maxKeyDepth);
}
/**
* Check if the given field corresponds to a dynamic key mapper of the
* form 'path_to_field.path_to_key'. If so, returns a field type that
* can be used to perform searches on this field. Otherwise returns null.
*/
MappedFieldType get(String field) {
if (mappers.isEmpty()) {
return null;
}
int dotIndex = -1;
int fieldDepth = 0;
while (true) {
if (++fieldDepth > maxKeyDepth) {
return null;
}
dotIndex = field.indexOf('.', dotIndex + 1);
if (dotIndex < 0) {
return null;
}
String parentField = field.substring(0, dotIndex);
String concreteField = aliasToConcreteName.getOrDefault(parentField, parentField);
DynamicKeyFieldMapper mapper = mappers.get(concreteField);
if (mapper != null) {
String key = field.substring(dotIndex + 1);
return mapper.keyedFieldType(key);
}
}
}
Iterator fieldTypes() {
return mappers.values().stream()
.map(mapper -> mapper.keyedFieldType(""))
.iterator();
}
// Visible for testing.
static int getMaxKeyDepth(Map dynamicKeyMappers,
Map aliasToConcreteName) {
int maxFieldDepth = 0;
for (Map.Entry entry : aliasToConcreteName.entrySet()) {
String aliasName = entry.getKey();
String path = entry.getValue();
if (dynamicKeyMappers.containsKey(path)) {
maxFieldDepth = Math.max(maxFieldDepth, fieldDepth(aliasName));
}
}
for (String fieldName : dynamicKeyMappers.keySet()) {
if (dynamicKeyMappers.containsKey(fieldName)) {
maxFieldDepth = Math.max(maxFieldDepth, fieldDepth(fieldName));
}
}
return maxFieldDepth;
}
/**
* Computes the total depth of this field by counting the number of parent fields
* in its path. As an example, the field 'parent1.parent2.field' has depth 3.
*/
private static int fieldDepth(String field) {
int numDots = 0;
int dotIndex = -1;
while (true) {
dotIndex = field.indexOf('.', dotIndex + 1);
if (dotIndex < 0) {
break;
}
numDots++;
}
return numDots + 1;
}
}