Java tutorial
/* Copyright (c) 2012-2014 Jakub Biaek * * 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 com.google.code.ssm.transcoders; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertNotNull; import java.io.IOException; import java.util.Arrays; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; import org.junit.Test; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.core.Version; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.SerializerProvider; import com.fasterxml.jackson.databind.jsontype.TypeSerializer; import com.fasterxml.jackson.databind.module.SimpleModule; import com.google.code.ssm.mapper.JsonObjectMapper; import com.google.code.ssm.providers.CachedObject; import com.google.code.ssm.test.Point; /** * * @author Jakub Biaek * */ public class JsonTranscoderTest { private JsonTranscoder transcoder; @Test public void testEncodeAndDecode() { transcoder = new JsonTranscoder(new JsonObjectMapper()); Point p = new Point(40, 50); CachedObject co = transcoder.encode(p); assertNotNull(co); assertNotNull(co.getData()); Point p2 = (Point) transcoder.decode(co); assertNotNull(p2); assertEquals(p, p2); } @Test public void testEncodeAndDecodeWithCustomSerializer() { JsonObjectMapper mapper = new JsonObjectMapper(); Map<Class<?>, JsonSerializer<?>> serializers = new HashMap<Class<?>, JsonSerializer<?>>(); serializers.put(Point.class, new PointSerializer()); mapper.setSerializers(serializers); transcoder = new JsonTranscoder(mapper); Point p = new Point(40, 50); // it won't be possible to deserialize it because no custom deserializer is registered and serialized data // doesn't contain info about class (type of serialized object), so the Jackson cannot figure out what // deserializer should be used CachedObject co = transcoder.encode(p); assertNotNull(co); assertNotNull(co.getData()); assertEquals("{\"v\":\"40x50\"}", new String(co.getData())); } @Test public void testEncodeAndDecodeRegisterSerializerDirectlyToModule() { JsonObjectMapper mapper = new JsonObjectMapper(); // first add serializer then register module SimpleModule module = new SimpleModule("cemo", Version.unknownVersion()); module.addSerializer(Point.class, new PointSerializer()); mapper.registerModule(module); transcoder = new JsonTranscoder(mapper); Point p = new Point(40, 50); CachedObject co = transcoder.encode(p); assertNotNull(co); assertNotNull(co.getData()); assertEquals("{\"v\":\"40x50\"}", new String(co.getData())); } @Test public void testEncodeAndDecodeWithCustomSerializerAndDeserializerWithTypeInfoInside() { JsonObjectMapper mapper = createMapper(); transcoder = new JsonTranscoder(mapper); Point p = new Point(40, 50); CachedObject co = transcoder.encode(p); assertNotNull(co); assertNotNull(co.getData()); assertEquals("{\"v\":{\"com.google.code.ssm.test.Point\":{\"c\":\"40x50\"}}}", new String(co.getData())); Point p2 = (Point) transcoder.decode(co); assertNotNull(p2); assertEquals(p, p2); } @Test public void testEncodeAndDecodeWithCustomSerializerAndDeserializerWithTypeInfoInsideAndShorterClassIdentifier() { JsonObjectMapper mapper = createMapper(); mapper.setClassToId(Collections.<Class<?>, String>singletonMap(Point.class, "point")); transcoder = new JsonTranscoder(mapper); Point p = new Point(40, 50); CachedObject co = transcoder.encode(p); assertNotNull(co); assertNotNull(co.getData()); assertEquals("{\"v\":{\"point\":{\"c\":\"40x50\"}}}", new String(co.getData())); Point p2 = (Point) transcoder.decode(co); assertNotNull(p2); assertEquals(p, p2); } @Test public void testEncodeAndDecodeListWithCustomSerializerAndDeserializerWithTypeInfoInsideAndShorterClassIdentifier() { JsonObjectMapper mapper = createMapper(); mapper.setClassToId(Collections.<Class<?>, String>singletonMap(Point.class, "point")); transcoder = new JsonTranscoder(mapper); List<Point> list = Arrays.asList(new Point(40, 50), new Point(10, 50)); CachedObject co = transcoder.encode(list); assertNotNull(co); assertNotNull(co.getData()); assertEquals( "{\"v\":{\"java.util.ArrayList\":[{\"point\":{\"c\":\"40x50\"}},{\"point\":{\"c\":\"10x50\"}}]}}", new String(co.getData())); @SuppressWarnings("unchecked") List<Point> list2 = (List<Point>) transcoder.decode(co); assertNotNull(list2); assertEquals(list, list2); } private JsonObjectMapper createMapper() { JsonObjectMapper mapper = new JsonObjectMapper(); Map<Class<?>, JsonSerializer<?>> serializers = new HashMap<Class<?>, JsonSerializer<?>>(); serializers.put(Point.class, new PointSerializerWithTypeInfo()); mapper.setSerializers(serializers); Map<Class<?>, JsonDeserializer<?>> deserializers = new HashMap<Class<?>, JsonDeserializer<?>>(); deserializers.put(Point.class, new PointDeserializer()); mapper.setDeserializers(deserializers); return mapper; } static class PointSerializer extends JsonSerializer<Point> { @Override public void serialize(final Point value, final JsonGenerator jgen, final SerializerProvider provider) throws IOException { jgen.writeString(value.getX() + "x" + value.getY()); } @Override public void serializeWithType(final Point value, final JsonGenerator jgen, final SerializerProvider provider, final TypeSerializer typeSer) throws IOException, JsonProcessingException { serialize(value, jgen, provider); } } /** * Stores information of Point type, it is used by Jackson to decide what deserializer should be used. * */ static class PointSerializerWithTypeInfo extends JsonSerializer<Point> { @Override public void serialize(final Point value, final JsonGenerator jgen, final SerializerProvider provider) throws IOException { jgen.writeFieldName("c"); jgen.writeString(value.getX() + "x" + value.getY()); } @Override public void serializeWithType(final Point value, final JsonGenerator jgen, final SerializerProvider provider, final TypeSerializer typeSer) throws IOException, JsonProcessingException { typeSer.writeTypePrefixForObject(value, jgen); serialize(value, jgen, provider); typeSer.writeTypeSuffixForObject(value, jgen); } } static class PointDeserializer extends JsonDeserializer<Point> { @Override public Point deserialize(final JsonParser jp, final DeserializationContext ctxt) throws IOException, JsonProcessingException { jp.nextToken(); String value = jp.nextTextValue(); jp.nextToken(); String[] parts = value.split("x"); return new Point(Integer.valueOf(parts[0]), Integer.valueOf(parts[1])); } } }