com.crushpaper.JsonNodeHelper.java Source code

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Here is the source code for com.crushpaper.JsonNodeHelper.java

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/*
Copyright 2015 CrushPaper.com.
    
This file is part of CrushPaper.
    
CrushPaper is free software: you can redistribute it and/or modify
it under the terms of version 3 of the GNU Affero General Public
License as published by the Free Software Foundation.
    
CrushPaper is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.
    
You should have received a copy of the GNU Affero General Public License
along with CrushPaper.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.crushpaper;

import java.io.IOException;

import com.fasterxml.jackson.databind.JsonNode;

/**
 * A class that wraps the JsonNode so that less code is required for common
 * functions.
 */
public class JsonNodeHelper {
    JsonNodeHelper(JsonNode node) {
        this.node = node;
    }

    /**
     * Returns the string value for the key, null if it does not exist, or
     * throws an exception if the value is not a string.
     * 
     * @throws IOException
     */
    public String getString(String key) throws IOException {
        JsonNode value = node.get(key);
        if (value == null) {
            return null;
        }

        if (!value.isTextual()) {
            throw new IOException();
        }

        return value.asText();
    }

    /**
     * Returns the string array value for the key, null if it does not exist, or
     * throws an exception if the value is not an array of strings.
     * 
     * @throws IOException
     */
    public String[] getStringArray(String key) throws IOException {
        JsonNode value = node.get(key);
        if (value == null) {
            return null;
        }

        if (!value.isArray()) {
            throw new IOException();
        }

        int size = value.size();
        String[] values = new String[size];
        for (int i = 0; i < size; ++i) {
            JsonNode element = value.get(i);
            if (element == null) {
                throw new IOException();
            }

            if (!element.isTextual()) {
                throw new IOException();
            }

            values[i] = element.asText();
        }

        return values;
    }

    /**
     * Returns the json array for the key, null if it does not exist, or throws
     * an exception if the value is not an array of objects.
     * 
     * @throws IOException
     */
    public JsonNodeHelper[] getJsonArray(String key) throws IOException {
        JsonNode value = node.get(key);
        if (value == null) {
            return null;
        }

        if (!value.isArray()) {
            throw new IOException();
        }

        int size = value.size();
        JsonNodeHelper[] values = new JsonNodeHelper[size];
        for (int i = 0; i < size; ++i) {
            JsonNode element = value.get(i);
            if (element == null) {
                throw new IOException();
            }

            if (!element.isObject()) {
                throw new IOException();
            }

            values[i] = new JsonNodeHelper(element);
        }

        return values;
    }

    /**
     * Returns the boolean value for the key, false if it does not exist, or
     * throws an exception if the value is not a boolean.
     * 
     * @throws IOException
     */
    public boolean getBoolean(String key) throws IOException {
        JsonNode value = node.get(key);

        if (value == null) {
            return false;
        }

        if (!value.isBoolean()) {
            throw new IOException();
        }

        return value.asBoolean();
    }

    private JsonNode node;

    /**
     * Returns the long value for the key, false if it does not exist, or throws
     * an exception if the value is not a long.
     * 
     * @throws IOException
     */
    public Long getLong(String key) throws IOException {
        JsonNode value = node.get(key);

        if (value == null) {
            return null;
        }

        if (!value.isNumber()) {
            throw new IOException();
        }

        return value.asLong();
    }
}