Java tutorial
/* * Copyright (c) 2014-2015 Red Hat, Inc. and/or its affiliates. * * 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: * Cheng Fang - Initial API and implementation */ package org.jberet.support.io; import javax.batch.api.BatchProperty; import javax.inject.Inject; import javax.naming.InitialContext; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.databind.MappingJsonFactory; import com.fasterxml.jackson.databind.ObjectMapper; /** * Base class for {@link org.jberet.support.io.JsonItemReader} and {@link org.jberet.support.io.JsonItemWriter}. * It also holds Json-related common batch properties for customizing Json processing. * * @see JsonItemReader * @see JsonItemWriter * @since 1.0.2 */ public abstract class JsonItemReaderWriterBase extends ItemReaderWriterBase { /** * A comma-separated list of key-value pairs that specify {@code com.fasterxml.jackson.core.JsonFactory.Feature}s. * Optional property and defaults to null. Only keys and values defined in * {@code com.fasterxml.jackson.core.JsonFactory.Feature} are accepted. For example, * <p> * <pre> * INTERN_FIELD_NAMES=false, CANONICALIZE_FIELD_NAMES=false * </pre> * * @see "com.fasterxml.jackson.core.JsonFactory.Feature" * @see NoMappingJsonFactoryObjectFactory#configureJsonFactoryFeatures(com.fasterxml.jackson.core.JsonFactory, java.lang.String) */ @Inject @BatchProperty protected String jsonFactoryFeatures; /** * A comma-separated list of key-value pairs that specify {@code com.fasterxml.jackson.databind.ObjectMapper} * features. Optional property and defaults to null. Only keys and values defined in * {@code com.fasterxml.jackson.databind.MapperFeature} are accepted. For example, * <p> * <pre> * USE_ANNOTATIONS=false, AUTO_DETECT_FIELDS=false, AUTO_DETECT_GETTERS=true * </pre> * * @see "com.fasterxml.jackson.databind.MapperFeature" * @see MappingJsonFactoryObjectFactory#configureMapperFeatures(com.fasterxml.jackson.databind.ObjectMapper, java.lang.String) */ @Inject @BatchProperty protected String mapperFeatures; /** * JNDI lookup name for {@code com.fasterxml.jackson.core.JsonFactory}, which is used for constructing * {@code com.fasterxml.jackson.core.JsonParser} in {@link org.jberet.support.io.JsonItemReader} and * {@code com.fasterxml.jackson.core.JsonGenerator} in {@link org.jberet.support.io.JsonItemWriter}. * Optional property and defaults to null. When this property is specified, its value is used to look up an * instance of {@code com.fasterxml.jackson.core.JsonFactory}, which is typically created and * administrated externally (e.g., inside application server). Otherwise, a new instance of * {@code com.fasterxml.jackson.core.JsonFactory} is created instead of lookup. * * @see "com.fasterxml.jackson.core.JsonFactory" */ @Inject @BatchProperty protected String jsonFactoryLookup; /** * A comma-separated list of key-value pairs that specify {@code com.fasterxml.jackson.databind.SerializationFeature}s. * Optional property and defaults to null. Only keys and values defined in * {@code com.fasterxml.jackson.databind.SerializationFeature} are accepted. For example, * <p> * <pre> * WRAP_ROOT_VALUE=true, INDENT_OUTPUT=true, FAIL_ON_EMPTY_BEANS=false * </pre> * * @see "com.fasterxml.jackson.databind.SerializationFeature" * @see MappingJsonFactoryObjectFactory#configureSerializationFeatures(com.fasterxml.jackson.databind.ObjectMapper, java.lang.String) */ @Inject @BatchProperty protected String serializationFeatures; /** * A comma-separated list of fully-qualified name of classes that implement * {@code com.fasterxml.jackson.databind.JsonSerializer}, which can serialize Objects of * arbitrary types into JSON. For example, * <p> * <pre> * org.jberet.support.io.JsonItemReaderTest$JsonSerializer, org.jberet.support.io.JsonItemReaderTest$JsonSerializer2 * </pre> * * @see "com.fasterxml.jackson.databind.JsonSerializer" * @see MappingJsonFactoryObjectFactory#configureCustomSerializersAndDeserializers */ @Inject @BatchProperty protected String customSerializers; /** * A comma-separated list of key-value pairs that specify {@code com.fasterxml.jackson.databind.DeserializationFeature}s. * Optional property and defaults to null. Only keys and values defined in * {@code com.fasterxml.jackson.databind.DeserializationFeature} are accepted. For example, * <p> * <pre> * USE_BIG_DECIMAL_FOR_FLOATS=true, USE_BIG_INTEGER_FOR_INTS=true, USE_JAVA_ARRAY_FOR_JSON_ARRAY=true * </pre> * @see "com.fasterxml.jackson.databind.DeserializationFeature" * @see MappingJsonFactoryObjectFactory#configureDeserializationFeatures(com.fasterxml.jackson.databind.ObjectMapper, java.lang.String) */ @Inject @BatchProperty protected String deserializationFeatures; /** * A comma-separated list of fully-qualified name of classes that implement * {@code com.fasterxml.jackson.databind.JsonDeserializer}, which can deserialize Objects of * arbitrary types from JSON. For example, * <p> * <pre> * org.jberet.support.io.JsonItemReaderTest$JsonDeserializer, org.jberet.support.io.JsonItemReaderTest$JsonDeserializer2 * </pre> * * @see "com.fasterxml.jackson.databind.JsonDeserializer" * @see MappingJsonFactoryObjectFactory#configureCustomSerializersAndDeserializers */ @Inject @BatchProperty protected String customDeserializers; /** * A comma-separated list of Jackson datatype module type ids that extend {@code com.fasterxml.jackson.databind.Module}. * These modules will be registered with {@link #objectMapper}. For example, * <p> * <pre> * com.fasterxml.jackson.datatype.joda.JodaModule, com.fasterxml.jackson.datatype.jsr353.JSR353Module, com.fasterxml.jackson.datatype.jsr310.JSR310Module * </pre> * * @see MappingJsonFactoryObjectFactory#configureCustomSerializersAndDeserializers */ @Inject @BatchProperty protected String customDataTypeModules; protected JsonFactory jsonFactory; protected ObjectMapper objectMapper; /** * Registers any {@code com.fasterxml.jackson.databind.module.SimpleModule} to the {@link #objectMapper}. Any number * of custom serializers or deserializers can be added to the module. */ protected void registerModule() throws Exception { MappingJsonFactoryObjectFactory.configureCustomSerializersAndDeserializers(objectMapper, customSerializers, customDeserializers, customDataTypeModules, getClass().getClassLoader()); } /** * Initializes {@code JsonFactory} or its subtypes, e.g., {@code com.fasterxml.jackson.dataformat.xml.XmlFactory}, * or {@code com.fasterxml.jackson.dataformat.csv.CsvFactory}. The factory should be initialized with a valid * {@code ObjectMapper}. * * Subclass may override this method to use different concrete types of {@code JsonFactory}. * * @throws Exception * @since 1.2.0.Alpha1 */ protected void initJsonFactory() throws Exception { if (jsonFactoryLookup != null) { jsonFactory = InitialContext.doLookup(jsonFactoryLookup); } else { jsonFactory = new MappingJsonFactory(); } } /** * Initializes {@link #jsonFactory} and {@link #objectMapper} fields, which may be instantiated or obtained from * other part of the application. This method also configures the {@link #jsonFactory}, {@link #objectMapper}, * {@link #serializationFeatures}, {@link #deserializationFeatures}, {@link #customDeserializers}, and * {@link #customSerializers} properly based on the current batch artifact properties. */ protected void initJsonFactoryAndObjectMapper() throws Exception { initJsonFactory(); objectMapper = (ObjectMapper) jsonFactory.getCodec(); if (jsonFactoryFeatures != null) { NoMappingJsonFactoryObjectFactory.configureJsonFactoryFeatures(jsonFactory, jsonFactoryFeatures); } if (mapperFeatures != null) { MappingJsonFactoryObjectFactory.configureMapperFeatures(objectMapper, mapperFeatures); } if (deserializationFeatures != null) { MappingJsonFactoryObjectFactory.configureDeserializationFeatures(objectMapper, deserializationFeatures); } if (serializationFeatures != null) { MappingJsonFactoryObjectFactory.configureSerializationFeatures(objectMapper, serializationFeatures); } registerModule(); } }