me.snowdrop.istio.api.internal.MixerResourceDeserializer Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of istio-common Show documentation
Common classes used by Istio Java API
The newest version!
/**
 * Copyright 2020 Red Hat, Inc. and/or its affiliates.
 *
 * 
 * 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 me.snowdrop.istio.api.internal;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.ObjectCodec;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Type;
import java.util.Iterator;
import java.util.Map;

/**
 * @author Christophe Laprun
 */
public interface MixerResourceDeserializer {

	String POLYMORPHIC_PARAMS_FIELD = "params";
	String INSTANCE_TYPE_FIELD = "compiledTemplate";
	String HANDLER_TYPE_FIELD = "compiledAdapter";

	default Object deserialize(JsonParser parser, String resourceType) throws IOException {
		ObjectCodec codec = parser.getCodec();
		final ObjectNode node = codec.readTree(parser);

		final Spec newInstance = newInstance();
		final Class instanceClass = newInstance.getClass();
		final Iterator> fields = node.fields();
		while (fields.hasNext()) {
			final Map.Entry field = fields.next();
			final String fieldName = field.getKey();

			try {
				final Field targetClassField = instanceClass.getDeclaredField(fieldName);
				final Class targetClass;
				if (fieldName.equals(POLYMORPHIC_PARAMS_FIELD)) {
					final String resourceName = node.findValue(resourceType).textValue();
					targetClass = getImplementationClass(resourceName);
				} else {
					final Type type = targetClassField.getAnnotatedType().getType();
					targetClass = (Class) type;
				}
				targetClassField.setAccessible(true);

				final Object deserialized = codec.treeToValue(field.getValue(), targetClass);
				targetClassField.set(newInstance, deserialized);
			} catch (NoSuchFieldException | IllegalAccessException e) {
				throw new RuntimeException(e);
			}
		}
		return newInstance;
	}

	Spec newInstance();

	Class getImplementationClass(String resourceType);
}