Java tutorial
/* * Copyright 2016 the Cook-E development team * * This file is part of Cook-E. * * Cook-E is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Cook-E 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Cook-E. If not, see <http://www.gnu.org/licenses/>. */ package org.cook_e.data; import java.text.ParseException; import java.util.ArrayList; import java.util.List; import org.joda.time.Duration; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; /** * This class represents a parser that allows for transforming recipes to strings and strings to recipes */ public class StorageParser { /** * Parses a serialized list of steps * @param stepsString a string representing a list of steps, in the format returned by * {@link #serializeRecipeSteps(List)} * @return the steps in the provided String * @throws java.text.ParseException if the steps could not be parsed */ public List<Step> parseRecipeSteps(String stepsString) throws ParseException { try { final JSONArray json = new JSONArray(stepsString); final List<Step> steps = new ArrayList<>(json.length()); for (int i = 0; i < json.length(); i++) { final JSONObject stepJson = json.getJSONObject(i); final String description = stepJson.getString("description"); final Duration duration = Duration.millis(stepJson.getLong("duration_ms")); final boolean simultaneous = stepJson.getBoolean("simultaneous"); final JSONArray ingredientsJson = stepJson.getJSONArray("ingredients"); final List<String> ingredients = new ArrayList<>(ingredientsJson.length()); for (int j = 0; j < ingredientsJson.length(); j++) { ingredients.add(ingredientsJson.getString(j)); } steps.add(new Step(ingredients, description, duration, simultaneous, i)); } return steps; } catch (JSONException e) { final ParseException parseException = new ParseException("Invalid JSON", 0); parseException.initCause(e); throw parseException; } } /** * Serializes a list of steps into a String in an implementation-defined format * @param steps the steps to process. Must not be null. Must not contain any null elements. * @return a String representation of the steps */ public String serializeRecipeSteps(List<? extends Step> steps) { Objects.requireNonNull(steps, "steps must not be null"); try { JSONArray json = new JSONArray(); for (Step step : steps) { final JSONObject stepJson = new JSONObject(); stepJson.put("description", step.getDescription()); stepJson.put("duration_ms", step.getTime().getMillis()); final JSONArray ingredientsJson = new JSONArray(step.getIngredients()); stepJson.put("ingredients", ingredientsJson); stepJson.put("simultaneous", step.isSimultaneous()); json.put(stepJson); } // Convert to a string with no indentation return json.toString(); } catch (JSONException e) { throw new RuntimeException("Unexpected exception serializing JSON", e); } } }