JsonVisitorRewriteBeans.java example

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jena-sparql-api-master
package org.aksw.jena_sparql_api.batch.json.rewriters;

import java.util.Map.Entry;

import org.aksw.gson.utils.JsonUtils;
import org.aksw.gson.utils.JsonVisitorRewrite;
import org.aksw.spring.json.ContextProcessorJsonUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.support.ManagedList;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;

public class JsonVisitorRewriteBeans
    extends JsonVisitorRewrite
{
    protected Gson gson;

    public JsonVisitorRewriteBeans() {
        this(new Gson());
    }

    public JsonVisitorRewriteBeans(Gson gson) {
        this.gson = gson;
    }


    public static JsonElement expandJava(Gson gson, JsonElement json) {
        JsonElement result = json.isJsonNull()
            ? json
            : expandObjectJava(gson, json);

        return result;
    }

    public static JsonObject expandObjectJava(Gson gson, JsonElement json) {
        JsonObject result;

        if(json.isJsonObject()) {
            result = json.getAsJsonObject();
        } else if(json.isJsonArray()) {
            result = expandJavaArray(gson, json.getAsJsonArray());
        } else if(json.isJsonPrimitive()) {
            result = expandJavaPrimitive(gson, json.getAsJsonPrimitive());
        } else {
            throw new RuntimeException("Should not happen");
        }

        return result;
    }

    public static JsonObject expandJavaArray(Gson gson, JsonArray json) {
        JsonObject result = new JsonObject();
        result.addProperty("type", "org.springframework.beans.factory.support.ManagedList");
        result.add("ctor", json);

        return result;
    }

    public static JsonObject expandJavaPrimitive(Gson gson, JsonPrimitive json) {
        Object val = gson.fromJson(json, Object.class);
        Class<?> clazz = val.getClass();

        JsonArray ctorArgs = new JsonArray();
        ctorArgs.add(json);

        JsonObject result = new JsonObject();
        result.addProperty("type", clazz.getName());
        result.add("ctor", ctorArgs);

        return result;
    }


    public static JsonElement processValue(Gson gson, JsonElement json, String qualifier) {
        JsonElement result;
        if(!StringUtils.isEmpty(qualifier) && !(json.isJsonObject() && json.getAsJsonObject().has("qualifier"))) {
            JsonElement tmp = expandJava(gson, json);
            if(tmp.isJsonObject()) {
                JsonObject o = tmp.getAsJsonObject();
                o.addProperty("qualifier", qualifier);
            }

            result = tmp;
        } else {
            result = json;
        }

        return result;
    }

    @Override
    public JsonElement visit(JsonObject json) {
        JsonObject tmp = new JsonObject();


        // Iterate the keys and check for qualifiers
        boolean isChange = false;
        for(Entry<String, JsonElement> entry : json.entrySet()) {
            String key = entry.getKey();
            Entry<String, String> keyAndQualifier = ContextProcessorJsonUtils.splitByQualifier(key);

            String qualifier = keyAndQualifier.getValue();
            JsonElement value = entry.getValue();

            JsonElement newValue = processValue(gson, value, qualifier);
            isChange = isChange || !value.equals(newValue);

            tmp.add(key, newValue);
        }

        JsonObject result = isChange ? tmp : json;

        return result;
    }
}