org.sindice.rdfcommons.beanmapper.BeanDeserializer.java Source code

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Here is the source code for org.sindice.rdfcommons.beanmapper.BeanDeserializer.java

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/*
 * Copyright 2008-2010 Digital Enterprise Research Institute (DERI)
 *
 * 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 org.sindice.rdfcommons.beanmapper;

import org.sindice.rdfcommons.storage.ResultSet;
import org.apache.commons.beanutils.BeanMap;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.Set;

/**
 * Bean deserializer implementation.
 *
 * @author Michele Mostarda ( mostarda@fbk.eu )
 * @version $Id$
 */
public class BeanDeserializer extends BaseDeserializer {

    public boolean acceptClass(Class clazz, Annotation[] annotations) {
        return !isPrimitive(clazz);
    }

    public Identifier getIdentifier(Class clazz, Annotation[] annotations) {
        throw new UnsupportedOperationException();
    }

    @SuppressWarnings("unchecked")
    public <T> T deserialize(DeserializationContext context, Class<T> clazz, Annotation[] annotations,
            Identifier identifier, QueryEndpoint endPoint) throws DeserializationException {

        final T bean;
        try {
            bean = clazz.newInstance();
        } catch (Exception e) {
            throw new DeserializationException("Error while instantiating object.", e);
        }
        context.registerInstance(identifier, bean);

        final String classUrl = getClassURL(bean.getClass());
        final BeanMap beanMap = new BeanMap(bean);
        String propertyURL;
        for (Map.Entry<String, Object> entry : (Set<Map.Entry<String, Object>>) beanMap.entrySet()) {

            // Skipping self description.
            if ("class".equals(entry.getKey())) {
                continue;
            }

            final String propertyName = entry.getKey();
            final Method propertyWriteMethod = beanMap.getWriteMethod(propertyName);
            if (propertyWriteMethod == null) {
                throw new DeserializationException(
                        String.format("Cannot find setter for property '%s' in bean %s", propertyName, bean));
            }
            final Class propertyType = propertyWriteMethod.getParameterTypes()[0];

            // Skipping properties marked as ignored.
            if (isIgnored(propertyWriteMethod)) {
                continue;
            }

            final Object value = retrieveObject(classUrl, propertyName, propertyWriteMethod, identifier, endPoint,
                    context);

            // Skipping missing values.
            if (value == null) {
                continue;
            }

            Object deserializedValue = context.deserialize(context, propertyType,
                    propertyWriteMethod.getAnnotations(), new Identifier(value, Identifier.Type.resource),
                    endPoint);

            try {
                propertyWriteMethod.invoke(bean, deserializedValue);
            } catch (Exception e) {
                throw new DeserializationException(
                        String.format("Error while setting value [%s] on bean [%s] using setter [%s].", value, bean,
                                propertyWriteMethod),
                        e);
            }
        }

        return bean;
    }

    private Object retrieveObject(String classUrl, String propertyName, Method propertyWriteMethod,
            Identifier identifier, QueryEndpoint endPoint, DeserializationContext context) {
        final String propertyURL = getPropertyURL(classUrl, propertyName, propertyWriteMethod);
        endPoint.addQuery((String) identifier.getId(), propertyURL, "?value");
        ResultSet rs = endPoint.execute();
        if (!rs.hasNext()) {
            context.reportIssue(String.format("Cannot find triple for identifier [%s] and property[%s].",
                    identifier, propertyURL));
            return null;
        }
        return rs.getVariableValue("?value");
    }

}