org.kurento.modulecreator.codegen.JsonFusioner.java Source code

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Here is the source code for org.kurento.modulecreator.codegen.JsonFusioner.java

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/*
 * (C) Copyright 2016 Kurento (http://kurento.org/)
 *
 * 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.
 *
 */
package org.kurento.modulecreator.codegen;

import java.io.IOException;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonIOException;
import com.google.gson.JsonObject;
import com.google.gson.JsonSyntaxException;

public class JsonFusioner {

    private static final Logger log = LoggerFactory.getLogger(JsonFusioner.class);

    private static final Gson gson = new GsonBuilder().setPrettyPrinting().disableHtmlEscaping().create();

    private final Path generatedJson;
    private final Path customizerJson;
    private final Path outputFile;

    private final Set<String> addChildrenTags;
    private final Set<String> replaceChildrenTags;

    public JsonFusioner(Path generatedJson, Path customizerJson, Path outputFile) {
        this(generatedJson, customizerJson, outputFile, null, null);
    }

    public JsonFusioner(Path generatedJson, Path customizerJson, Path outputFile, String[] addChildrenTags,
            String[] replaceChildrenTags) {
        super();
        this.generatedJson = generatedJson;
        this.customizerJson = customizerJson;
        this.outputFile = outputFile;
        this.addChildrenTags = new HashSet<String>(Arrays.asList(addChildrenTags));
        this.replaceChildrenTags = new HashSet<String>(Arrays.asList(replaceChildrenTags));
    }

    public void fusionJsons() throws IOException {

        try {
            JsonObject generatedJsonDoc = loadJson(generatedJson);
            JsonObject customizedJsonDoc = loadJson(customizerJson);

            merge(generatedJsonDoc, customizedJsonDoc, new ArrayList<String>());

            writeJson(generatedJsonDoc);
        } catch (IOException e) {
            log.warn(
                    "Error while merging '" + generatedJson + "' with '" + customizerJson + "': " + e.getMessage());
        }
    }

    private void merge(JsonObject genNode, JsonObject custNode, List<String> genPath) {

        for (Entry<String, JsonElement> entry : custNode.entrySet()) {

            JsonElement custChildNode = entry.getValue();

            JsonElement genChildNode = genNode.get(entry.getKey());

            if (genChildNode != null) {

                String nodePath = getPath(genPath, entry.getKey());

                if (replaceChildrenTags.contains(nodePath)) {

                    if (custChildNode instanceof JsonObject && genChildNode instanceof JsonObject) {

                        List<String> newPath = new ArrayList<String>(genPath);
                        newPath.add(entry.getKey());

                        merge((JsonObject) genChildNode, (JsonObject) custChildNode, newPath);
                    }

                } else if (addChildrenTags.contains(nodePath)) {

                    addChildren(custChildNode, genChildNode);

                } else if (includedInReplaceOrAdd(nodePath)) {

                    if (custChildNode instanceof JsonObject && genChildNode instanceof JsonObject) {

                        List<String> newPath = new ArrayList<String>(genPath);
                        newPath.add(entry.getKey());

                        merge((JsonObject) genChildNode, (JsonObject) custChildNode, newPath);
                    }

                } else {

                    // Replace entire node
                    genNode.add(entry.getKey(), custChildNode);
                }

            } else {

                // Add new node
                genNode.add(entry.getKey(), custChildNode);
            }
        }
    }

    private void addChildren(JsonElement fromElement, JsonElement toElement) {

        if (fromElement instanceof JsonObject && toElement instanceof JsonObject) {

            JsonObject fromObject = (JsonObject) fromElement;
            JsonObject toObject = (JsonObject) toElement;

            for (Entry<String, JsonElement> entry : fromObject.entrySet()) {
                toObject.add(entry.getKey(), entry.getValue());
            }

        } else if (fromElement instanceof JsonArray && toElement instanceof JsonArray) {

            JsonArray fromArray = (JsonArray) fromElement;
            JsonArray toArray = (JsonArray) toElement;

            toArray.addAll(fromArray);
        }
    }

    private boolean includedInReplaceOrAdd(String nodePath) {

        for (String path : replaceChildrenTags) {
            if (path.startsWith(nodePath)) {
                return true;
            }
        }

        for (String path : addChildrenTags) {
            if (path.startsWith(nodePath)) {
                return true;
            }
        }

        return false;
    }

    private String getPath(List<String> path, String propName) {

        StringBuilder sb = new StringBuilder("/");
        for (String prop : path) {
            sb.append(prop).append("/");
        }
        sb.append(propName);
        return sb.toString();
    }

    private JsonObject loadJson(Path jsonPath) throws JsonSyntaxException, JsonIOException, IOException {

        return (JsonObject) gson.fromJson(Files.newBufferedReader(jsonPath, StandardCharsets.UTF_8),
                JsonElement.class);
    }

    private void writeJson(JsonObject doc) throws IOException {

        String json = gson.toJson(doc);
        try (Writer os = Files.newBufferedWriter(outputFile, StandardCharsets.UTF_8)) {
            os.write(json);
        }
    }
}