com.blazebit.persistence.impl.builder.object.ClassObjectBuilder Maven / Gradle / Ivy

/*
 * Copyright 2014 - 2020 Blazebit.
 *
 * 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.blazebit.persistence.impl.builder.object;

import java.lang.reflect.Constructor;
import java.util.List;

import com.blazebit.persistence.ObjectBuilder;
import com.blazebit.persistence.SelectBuilder;

/**
 *
 * @author Moritz Becker
 * @since 1.0.0
 */
public class ClassObjectBuilder implements ObjectBuilder {

    private final Class clazz;
    private Constructor constructor;

    public ClassObjectBuilder(Class clazz) {
        this.clazz = clazz;
    }

    @SuppressWarnings("unchecked")
    private Constructor getConstructor(Object[] tuple) {
        Constructor[] constructors = clazz.getConstructors();
        Constructor matchingConstr = null;
        for (Constructor constr : constructors) {
            Class[] paramTypes = constr.getParameterTypes();
            if (paramTypes.length == tuple.length) {
                boolean match = true;
                for (int i = 0; i < paramTypes.length; i++) {
                    if (tuple[i] != null && !paramTypes[i].isAssignableFrom(tuple[i].getClass())) {
                        match = false;
                        break;
                    }
                }
                if (match == true) {
                    if (matchingConstr != null) {
                        throw new RuntimeException("Multiple constructors matching");
                    }
                    return (Constructor) constr;
                }

            }
        }

        throw new RuntimeException("No matching constructor");
    }

    @Override
    public T build(Object[] tuple) {
        if (constructor == null) {
            constructor = getConstructor(tuple);
        }

        try {
            return constructor.newInstance(tuple);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public List buildList(List list) {
        return list;
    }

    @Override
    public > void applySelects(X queryBuilder) {
    }

}