it.intecs.pisa.util.json.JsonXpath.java Source code

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Here is the source code for it.intecs.pisa.util.json.JsonXpath.java

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/* Copyright (c) 2013 Intecs - www.intecs.it. All rights reserved.
 * This code is licensed under the GPL 3.0 license, available at the root
 * application directory.
*/
package it.intecs.pisa.util.json;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import java.util.StringTokenizer;

/**
 *
 * @author massi
 */
public class JsonXpath {
    public static String getString(JsonObject obj, String xpath) {
        StringTokenizer tokenizer;

        tokenizer = new StringTokenizer(xpath, "/");

        Object selectedObject;
        selectedObject = get(obj, tokenizer);

        JsonPrimitive primitive;
        primitive = (JsonPrimitive) selectedObject;

        return (String) primitive.getAsString();
    }

    private static Object get(JsonObject obj, StringTokenizer tokenizer) {
        String tok;

        tok = tokenizer.nextToken();
        JsonArray array;
        JsonObject focusedObj;

        String token;
        if (tok.endsWith("]")) {
            String index;
            index = tok.substring(tok.indexOf("[") + 1, tok.indexOf("]"));

            String tokenName;
            tokenName = tok.substring(0, tok.indexOf("["));

            array = obj.getAsJsonArray(tokenName);
            JsonElement a = array.get(Integer.valueOf(index) - 1);
            if (a instanceof JsonPrimitive)
                return a;
            else
                focusedObj = a.getAsJsonObject();
        } else
            focusedObj = obj;

        return focusedObj.get(tok);

    }

    public static boolean exists(JsonObject obj, String xpath) {
        try {
            StringTokenizer tokenizer;

            tokenizer = new StringTokenizer(xpath, "/");

            Object selectedObject;
            selectedObject = get(obj, tokenizer);
            if (selectedObject == null)
                return false;
            else
                return true;
        } catch (Exception e) {
            return false;
        }
    }
}