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/*
* ============LICENSE_START====================================
* DCAEGEN2-SERVICES-SDK
* =========================================================
* Copyright (C) 2019 Nokia. All rights reserved.
* =========================================================
* Licensed 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.
* ============LICENSE_END=====================================
*/
package org.onap.dcaegen2.services.sdk.rest.services.cbs.client.api.listener;
import static java.lang.String.valueOf;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import io.vavr.collection.List;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.jetbrains.annotations.NotNull;
/**
* Class responsible for creating MerkleTree structure from JsonObject.
*
* @since 1.1.2
*/
class MerkleTreeParser {
/**
* <p> Method used to parse {@link JsonObject} into {@link MerkleTree} structure.</p>
* <p> The algorithm will recursively create mapping of (path in tree)->(value) from JsonObject
* and use it to create MerkleTree by means of {@link MerkleTree#add(List, Object)} method. </p>
* <p> Each JsonObject will append it's key to path until value of primitive type is encountered.
* For each JsonArray element artificial path is created by creating lables from sequential integers.
* This results in array split into multiple nodes in MerkleTree structure.</p>
*
* <p>Example. For JsonObject:
* <pre>
* {
* "p1": "v1",
* "p2": ["v2", "v3"]
* "p3": {
* "p4": "v4"
* }
* }
* </pre>
* following map would be created:</p>
* <pre>
* "v1" <- ["p1"]
* "v2" <- ["p2", "0"]
* "v3" <- ["p2", "1"]
* "v4" <- ["p3", "p4"]
* </pre>
*
* @param json JsonObject to be parsed
* @since 1.1.2
*/
MerkleTree<String> fromJsonObject(final @NotNull JsonObject json) {
MerkleTree<String> tree = MerkleTree.emptyWithDefaultDigest(String::getBytes);
for (Entry<String, JsonElement> entry : json.entrySet()) {
tree = treeEnhancedWithEntry(tree, entry);
}
return tree;
}
private MerkleTree<String> treeEnhancedWithEntry(final MerkleTree<String> tree,
final Entry<String, JsonElement> entry) {
return createTreeFromValuesPaths(tree, pathsToValues(entry, List.empty()));
}
private Map<List<String>, String> pathsToValues(Entry<String, JsonElement> entry, List<String> elementPathPrefix) {
return pathsToValuesFromJsonElement(entry.getKey(), entry.getValue(), elementPathPrefix);
}
private Map<List<String>, String> pathsToValuesFromJsonElement(final String jsonKey,
final JsonElement element,
final List<String> elementPathPrefix) {
final HashMap<List<String>, String> pathToValue = new HashMap<>();
final List<String> newPrefix = elementPathPrefix.append(jsonKey);
if (element.isJsonObject()) {
element.getAsJsonObject()
.entrySet()
.forEach(entry -> pathToValue.putAll(pathsToValues(entry, newPrefix)));
} else if (element.isJsonArray()) {
pathToValue.putAll(handleArray(newPrefix, element.getAsJsonArray()));
} else if (element.isJsonPrimitive()) {
pathToValue.put(newPrefix, element.getAsString());
} else if (element.isJsonNull()) {
pathToValue.put(newPrefix, null);
}
return pathToValue;
}
private HashMap<List<String>, String> handleArray(List<String> newPrefix, JsonArray jsonArray) {
final HashMap<List<String>, String> hashMap = new HashMap<>();
int labelIndex = 0;
for (JsonElement jsonElement : jsonArray) {
String jsonKey = valueOf(labelIndex++);
hashMap.putAll(pathsToValuesFromJsonElement(jsonKey, jsonElement, newPrefix));
}
return hashMap;
}
private MerkleTree<String> createTreeFromValuesPaths(MerkleTree<String> tree,
final Map<List<String>, String> pathToValue) {
for (Entry<List<String>, String> entry : pathToValue.entrySet()) {
List<String> path = entry.getKey();
String value = entry.getValue();
tree = tree.add(path, value);
}
return tree;
}
}
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