Java tutorial
/* * The MIT License (MIT) * * Copyright (c) 2016 Eslam Nawara * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package io.acme.solution.domain.util; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.HashMap; /** * A builder class for creating/reading mementos */ public class MementoBuilder { private static final Logger log = LoggerFactory.getLogger(MementoBuilder.class); public static String flatten(final HashMap<String, Object> attributesMap) { final ObjectMapper mapper = new ObjectMapper(); try { return mapper.writeValueAsString(attributesMap); } catch (JsonProcessingException exception) { log.debug("Failed to craete memento object"); log.trace("Failed to create memento object for the passed attributes map", exception); return null; } } public static HashMap<String, Object> construct(final String state) { final ObjectMapper mapper = new ObjectMapper(); try { return (HashMap<String, Object>) mapper.readValue(state, HashMap.class); } catch (IOException exception) { log.debug("Failed to reconstruct memento object"); log.trace("Failed to reconstruct the memento attributes map", exception); return null; } } }