com.googlecode.jsonschema2pojo.SchemaGenerator Maven / Gradle / Ivy
/**
* Copyright © 2010-2011 Nokia
*
* Licensed 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 com.googlecode.jsonschema2pojo;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URL;
import java.util.Iterator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.jsonschema.SchemaAware;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.ser.BeanSerializerFactory;
import com.fasterxml.jackson.databind.ser.DefaultSerializerProvider;
import com.fasterxml.jackson.databind.ser.std.NullSerializer;
import com.googlecode.jsonschema2pojo.exception.GenerationException;
public class SchemaGenerator {
private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
public ObjectNode schemaFromExample(URL example) {
try {
JsonNode content = OBJECT_MAPPER.readTree(new File(URI.create(example.toString())));
return schemaFromExample(content);
} catch (IOException e) {
throw new GenerationException("Could not process JSON in source file", e);
}
}
public ObjectNode schemaFromExample(JsonNode example) {
if (example.isObject()) {
return objectSchema(example);
} else if (example.isArray()) {
return arraySchema(example);
} else {
return simpleTypeSchema(example);
}
}
private ObjectNode objectSchema(JsonNode exampleObject) {
ObjectNode schema = OBJECT_MAPPER.createObjectNode();
schema.put("type", "object");
ObjectNode properties = OBJECT_MAPPER.createObjectNode();
for (Iterator iter = exampleObject.fieldNames(); iter.hasNext();) {
String property = iter.next();
properties.put(property, schemaFromExample(exampleObject.get(property)));
}
schema.put("properties", properties);
return schema;
}
private ObjectNode arraySchema(JsonNode exampleArray) {
ObjectNode schema = OBJECT_MAPPER.createObjectNode();
schema.put("type", "array");
if (exampleArray.size() > 0) {
JsonNode exampleItem = exampleArray.get(0).isObject() ? mergeArrayItems(exampleArray) : exampleArray.get(0);
schema.put("items", schemaFromExample(exampleItem));
}
return schema;
}
private JsonNode mergeArrayItems(JsonNode exampleArray) {
ObjectNode mergedItems = OBJECT_MAPPER.createObjectNode();
for (JsonNode item : exampleArray) {
if (item.isObject()) {
mergedItems.putAll((ObjectNode) item);
}
}
return mergedItems;
}
private ObjectNode simpleTypeSchema(JsonNode exampleValue) {
try {
Object valueAsJavaType = OBJECT_MAPPER.treeToValue(exampleValue, Object.class);
SchemaAware valueSerializer = getValueSerializer(valueAsJavaType);
return (ObjectNode) valueSerializer.getSchema(OBJECT_MAPPER.getSerializerProvider(), null);
} catch (JsonMappingException e) {
throw new GenerationException("Unable to generate a schema for this json example: " + exampleValue, e);
} catch (JsonProcessingException e) {
throw new GenerationException("Unable to generate a schema for this json example: " + exampleValue, e);
}
}
private SchemaAware getValueSerializer(Object valueAsJavaType) throws JsonMappingException {
SerializerProvider serializerProvider = new DefaultSerializerProvider.Impl().createInstance(OBJECT_MAPPER.getSerializationConfig(), BeanSerializerFactory.instance);
if (valueAsJavaType == null) {
return NullSerializer.instance;
} else {
Class javaTypeForValue = valueAsJavaType.getClass();
JsonSerializer