org.lambdamatic.internal.elasticsearch.codec.ObjectMapperFactory.java Source code

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Here is the source code for org.lambdamatic.internal.elasticsearch.codec.ObjectMapperFactory.java

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/*******************************************************************************
 * Copyright (c) 2016 Red Hat. All rights reserved. This program and the accompanying materials are
 * made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Red Hat - Initial Contribution
 *******************************************************************************/

package org.lambdamatic.internal.elasticsearch.codec;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.reflections.Reflections;
import org.reflections.scanners.SubTypesScanner;
import org.reflections.scanners.TypeAnnotationsScanner;
import org.reflections.util.ClasspathHelper;
import org.reflections.util.ConfigurationBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;

/**
 * A factory for the {@link ObjectMapper}.
 */
public class ObjectMapperFactory {

    /** The usual Logger. */
    private static final Logger LOGGER = LoggerFactory.getLogger(ObjectMapperFactory.class);

    private static final ObjectMapperFactory instance = new ObjectMapperFactory();

    private ObjectMapper objectMapper;

    /**
     * Initializes an {@link ObjectMapper} configured with mixins to support serialization and
     * deserialization of all built-in and user-defined domain types.
     * <p>
     * <strong>Note:</strong>The {@link ObjectMapper} is instantiated and initialized once and then
     * kept in cache, so multiple calls will retrieve the same instance.
     * </p>
     * 
     * @return the {@link ObjectMapper}
     * 
     */
    public static ObjectMapper getObjectMapper() {
        if (instance.objectMapper == null) {
            LOGGER.info("Initializing the ObjectMapper");
            final ObjectMapper mapper = new ObjectMapper();
            final ExecutorService availableProcessorsThreadPool = Executors
                    .newFixedThreadPool(Runtime.getRuntime().availableProcessors());
            final Reflections reflections = new Reflections(new ConfigurationBuilder()

                    // TODO: allow for configuration settings to reduce the scope of searching, using package
                    // names instead of a classloader
                    .setUrls(ClasspathHelper.forJavaClassPath())
                    // .setUrls(ClasspathHelper.forClassLoader())
                    .setScanners(new SubTypesScanner(), new TypeAnnotationsScanner())
                    .setExecutorService(availableProcessorsThreadPool));
            // thread pool must be closed after it has been used, to avoid leaking threads in the JVM.
            availableProcessorsThreadPool.shutdown();
            // final Reflections reflections = new Reflections();
            reflections.getTypesAnnotatedWith(Mixin.class).stream().forEach(mixin -> {
                final Mixin mixinAnnotation = mixin.getAnnotation(Mixin.class);
                LOGGER.info("Adding mixin {} to {}", mixin, mixinAnnotation.target());
                mapper.addMixIn(mixinAnnotation.target(), mixin);
            });
            mapper.registerModule(new JavaTimeModule());
            // configure LocalDate serialization as string with pattern: YYYY-mm-dd
            mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
            instance.objectMapper = mapper;
        }
        return instance.objectMapper;
    }

}