Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.olingo.commons.core.serialization; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonGenerator; import org.apache.commons.lang3.ArrayUtils; import org.apache.commons.lang3.StringUtils; import org.apache.olingo.commons.api.Constants; import org.apache.olingo.commons.api.data.Annotatable; import org.apache.olingo.commons.api.data.Annotation; import org.apache.olingo.commons.api.data.Entity; import org.apache.olingo.commons.api.data.EntitySet; import org.apache.olingo.commons.api.data.Link; import org.apache.olingo.commons.api.data.Linked; import org.apache.olingo.commons.api.data.LinkedComplexValue; import org.apache.olingo.commons.api.data.Property; import org.apache.olingo.commons.api.data.ResWrap; import org.apache.olingo.commons.api.data.Valuable; import org.apache.olingo.commons.api.data.ValueType; import org.apache.olingo.commons.api.domain.ODataLinkType; import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeException; import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind; import org.apache.olingo.commons.api.edm.constants.ODataServiceVersion; import org.apache.olingo.commons.api.edm.geo.Geospatial; import org.apache.olingo.commons.api.serialization.ODataSerializer; import org.apache.olingo.commons.api.serialization.ODataSerializerException; import org.apache.olingo.commons.core.edm.EdmTypeInfo; import org.apache.olingo.commons.core.edm.primitivetype.EdmPrimitiveTypeFactory; import java.io.IOException; import java.io.Writer; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class JsonSerializer implements ODataSerializer { private static final EdmPrimitiveTypeKind[] NUMBER_TYPES = { EdmPrimitiveTypeKind.Byte, EdmPrimitiveTypeKind.SByte, EdmPrimitiveTypeKind.Single, EdmPrimitiveTypeKind.Double, EdmPrimitiveTypeKind.Int16, EdmPrimitiveTypeKind.Int32, EdmPrimitiveTypeKind.Int64, EdmPrimitiveTypeKind.Decimal }; private final JsonGeoValueSerializer geoSerializer = new JsonGeoValueSerializer(); protected ODataServiceVersion version; protected boolean serverMode; public JsonSerializer(final ODataServiceVersion version, final boolean serverMode) { this.version = version; this.serverMode = serverMode; } @Override public <T> void write(final Writer writer, final T obj) throws ODataSerializerException { try { final JsonGenerator json = new JsonFactory().createGenerator(writer); if (obj instanceof EntitySet) { new JsonEntitySetSerializer(version, serverMode).doSerialize((EntitySet) obj, json); } else if (obj instanceof Entity) { new JsonEntitySerializer(version, serverMode).doSerialize((Entity) obj, json); } else if (obj instanceof Property) { new JsonPropertySerializer(version, serverMode).doSerialize((Property) obj, json); } else if (obj instanceof Link) { link((Link) obj, json); } json.flush(); } catch (final IOException e) { throw new ODataSerializerException(e); } catch (final EdmPrimitiveTypeException e) { throw new ODataSerializerException(e); } } @SuppressWarnings("unchecked") @Override public <T> void write(final Writer writer, final ResWrap<T> container) throws ODataSerializerException { final T obj = container == null ? null : container.getPayload(); try { final JsonGenerator json = new JsonFactory().createGenerator(writer); if (obj instanceof EntitySet) { new JsonEntitySetSerializer(version, serverMode) .doContainerSerialize((ResWrap<EntitySet>) container, json); } else if (obj instanceof Entity) { new JsonEntitySerializer(version, serverMode).doContainerSerialize((ResWrap<Entity>) container, json); } else if (obj instanceof Property) { new JsonPropertySerializer(version, serverMode).doContainerSerialize((ResWrap<Property>) container, json); } else if (obj instanceof Link) { link((Link) obj, json); } json.flush(); } catch (final IOException e) { throw new ODataSerializerException(e); } catch (final EdmPrimitiveTypeException e) { throw new ODataSerializerException(e); } } protected void link(final Link link, final JsonGenerator jgen) throws IOException { jgen.writeStartObject(); jgen.writeStringField(Constants.JSON_URL, link.getHref()); jgen.writeEndObject(); } protected void links(final Linked linked, final JsonGenerator jgen) throws IOException, EdmPrimitiveTypeException { if (serverMode) { serverLinks(linked, jgen); } else { clientLinks(linked, jgen); } } protected void clientLinks(final Linked linked, final JsonGenerator jgen) throws IOException, EdmPrimitiveTypeException { final Map<String, List<String>> entitySetLinks = new HashMap<String, List<String>>(); for (Link link : linked.getNavigationLinks()) { for (Annotation annotation : link.getAnnotations()) { valuable(jgen, annotation, link.getTitle() + "@" + annotation.getTerm()); } ODataLinkType type = null; try { type = ODataLinkType.fromString(version, link.getRel(), link.getType()); } catch (IllegalArgumentException e) { // ignore } if (type == ODataLinkType.ENTITY_SET_NAVIGATION) { final List<String> uris; if (entitySetLinks.containsKey(link.getTitle())) { uris = entitySetLinks.get(link.getTitle()); } else { uris = new ArrayList<String>(); entitySetLinks.put(link.getTitle(), uris); } if (StringUtils.isNotBlank(link.getHref())) { uris.add(link.getHref()); } } else { if (StringUtils.isNotBlank(link.getHref())) { jgen.writeStringField(link.getTitle() + Constants.JSON_BIND_LINK_SUFFIX, link.getHref()); } } if (link.getInlineEntity() != null) { jgen.writeFieldName(link.getTitle()); new JsonEntitySerializer(version, serverMode).doSerialize(link.getInlineEntity(), jgen); } else if (link.getInlineEntitySet() != null) { jgen.writeArrayFieldStart(link.getTitle()); final JsonEntitySerializer entitySerializer = new JsonEntitySerializer(version, serverMode); for (Entity subEntry : link.getInlineEntitySet().getEntities()) { entitySerializer.doSerialize(subEntry, jgen); } jgen.writeEndArray(); } } for (Map.Entry<String, List<String>> entitySetLink : entitySetLinks.entrySet()) { if (!entitySetLink.getValue().isEmpty()) { jgen.writeArrayFieldStart(entitySetLink.getKey() + Constants.JSON_BIND_LINK_SUFFIX); for (String uri : entitySetLink.getValue()) { jgen.writeString(uri); } jgen.writeEndArray(); } } } protected void serverLinks(final Linked linked, final JsonGenerator jgen) throws IOException, EdmPrimitiveTypeException { if (linked instanceof Entity) { for (Link link : ((Entity) linked).getMediaEditLinks()) { if (StringUtils.isNotBlank(link.getHref())) { jgen.writeStringField( link.getTitle() + StringUtils.prependIfMissing( version.getJsonName(ODataServiceVersion.JsonKey.MEDIA_EDIT_LINK), "@"), link.getHref()); } } } for (Link link : linked.getAssociationLinks()) { if (StringUtils.isNotBlank(link.getHref())) { jgen.writeStringField( link.getTitle() + version.getJsonName(ODataServiceVersion.JsonKey.ASSOCIATION_LINK), link.getHref()); } } for (Link link : linked.getNavigationLinks()) { for (Annotation annotation : link.getAnnotations()) { valuable(jgen, annotation, link.getTitle() + "@" + annotation.getTerm()); } if (StringUtils.isNotBlank(link.getHref())) { jgen.writeStringField( link.getTitle() + version.getJsonName(ODataServiceVersion.JsonKey.NAVIGATION_LINK), link.getHref()); } if (link.getInlineEntity() != null) { jgen.writeFieldName(link.getTitle()); new JsonEntitySerializer(version, serverMode).doSerialize(link.getInlineEntity(), jgen); } else if (link.getInlineEntitySet() != null) { jgen.writeArrayFieldStart(link.getTitle()); JsonEntitySerializer entitySerializer = new JsonEntitySerializer(version, serverMode); for (Entity subEntry : link.getInlineEntitySet().getEntities()) { entitySerializer.doSerialize(subEntry, jgen); } jgen.writeEndArray(); } } } private void collection(final JsonGenerator jgen, final EdmTypeInfo typeInfo, final ValueType valueType, final List<?> value) throws IOException, EdmPrimitiveTypeException { jgen.writeStartArray(); for (Object item : value) { final EdmTypeInfo itemTypeInfo = typeInfo == null ? null : new EdmTypeInfo.Builder().setTypeExpression(typeInfo.getFullQualifiedName().toString()) .build(); switch (valueType) { case COLLECTION_PRIMITIVE: primitiveValue(jgen, itemTypeInfo, item); break; case COLLECTION_GEOSPATIAL: jgen.writeStartObject(); geoSerializer.serialize(jgen, (Geospatial) item); jgen.writeEndObject(); break; case COLLECTION_ENUM: jgen.writeString(item.toString()); break; case COLLECTION_COMPLEX: @SuppressWarnings("unchecked") final List<Property> complexItem = (List<Property>) item; complexValue(jgen, itemTypeInfo, complexItem, null); break; case COLLECTION_LINKED_COMPLEX: final LinkedComplexValue complexItem2 = (LinkedComplexValue) item; complexValue(jgen, itemTypeInfo, complexItem2.getValue(), complexItem2); break; default: } } jgen.writeEndArray(); } protected void primitiveValue(final JsonGenerator jgen, final EdmTypeInfo typeInfo, final Object value) throws IOException, EdmPrimitiveTypeException { final EdmPrimitiveTypeKind kind = typeInfo == null ? null : typeInfo.getPrimitiveTypeKind(); final boolean isNumber = kind == null ? value instanceof Number : ArrayUtils.contains(NUMBER_TYPES, kind); final boolean isBoolean = kind == null ? value instanceof Boolean : kind == EdmPrimitiveTypeKind.Boolean; if (value == null) { jgen.writeNull(); } else if (isBoolean) { jgen.writeBoolean((Boolean) value); } else { final String serialized = kind == null ? value.toString() // TODO: add facets : EdmPrimitiveTypeFactory.getInstance(kind).valueToString(value, null, null, Constants.DEFAULT_PRECISION, Constants.DEFAULT_SCALE, null); if (isNumber) { jgen.writeNumber(serialized); } else { jgen.writeString(serialized); } } } private void complexValue(final JsonGenerator jgen, final EdmTypeInfo typeInfo, final List<Property> value, final Linked linked) throws IOException, EdmPrimitiveTypeException { jgen.writeStartObject(); if (typeInfo != null) { jgen.writeStringField(version.getJsonName(ODataServiceVersion.JsonKey.TYPE), typeInfo.external(version)); } for (Property property : value) { valuable(jgen, property, property.getName()); } if (linked != null) { links(linked, jgen); } jgen.writeEndObject(); } private void value(final JsonGenerator jgen, final String type, final Valuable value) throws IOException, EdmPrimitiveTypeException { final EdmTypeInfo typeInfo = type == null ? null : new EdmTypeInfo.Builder().setTypeExpression(type).build(); if (value.isNull()) { jgen.writeNull(); } else if (value.isPrimitive()) { primitiveValue(jgen, typeInfo, value.asPrimitive()); } else if (value.isEnum()) { jgen.writeString(value.asEnum().toString()); } else if (value.isGeospatial()) { jgen.writeStartObject(); geoSerializer.serialize(jgen, value.asGeospatial()); jgen.writeEndObject(); } else if (value.isCollection()) { collection(jgen, typeInfo, value.getValueType(), value.asCollection()); } else if (value.isLinkedComplex()) { complexValue(jgen, typeInfo, value.asLinkedComplex().getValue(), value.asLinkedComplex()); } else if (value.isComplex()) { complexValue(jgen, typeInfo, value.asComplex(), null); } } protected void valuable(final JsonGenerator jgen, final Valuable valuable, final String name) throws IOException, EdmPrimitiveTypeException { if (!Constants.VALUE.equals(name) && !(valuable instanceof Annotation) && !valuable.isComplex() && !valuable.isLinkedComplex()) { String type = valuable.getType(); if (StringUtils.isBlank(type) && valuable.isPrimitive() || valuable.isNull()) { type = EdmPrimitiveTypeKind.String.getFullQualifiedName().toString(); } if (StringUtils.isNotBlank(type)) { jgen.writeFieldName(name + StringUtils.prependIfMissing(version.getJsonName(ODataServiceVersion.JsonKey.TYPE), "@")); jgen.writeString(new EdmTypeInfo.Builder().setTypeExpression(type).build().external(version)); } } if (valuable instanceof Annotatable) { for (Annotation annotation : ((Annotatable) valuable).getAnnotations()) { valuable(jgen, annotation, name + "@" + annotation.getTerm()); } } jgen.writeFieldName(name); value(jgen, valuable.getType(), valuable); } }