com.jporm.rm.query.find.FindQueryExecutionProvider Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright 2016 Francesco Cina'
 *
 * 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.jporm.rm.query.find;

import java.util.List;
import java.util.Optional;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;

import javax.swing.tree.RowMapper;

import com.jporm.commons.core.exception.JpoException;
import com.jporm.commons.core.exception.JpoNotUniqueResultException;
import com.jporm.commons.core.exception.JpoNotUniqueResultManyResultsException;
import com.jporm.commons.core.exception.JpoNotUniqueResultNoResultException;
import com.jporm.commons.core.util.GenericWrapper;
import com.jporm.persistor.BeanFromResultSet;
import com.jporm.persistor.Persistor;
import com.jporm.sql.query.select.SelectCommon;
import com.jporm.types.io.ResultEntry;

public interface FindQueryExecutionProvider extends SelectCommon {

    /**
     * Fetch the bean
     *
     * @return
     */
    public default BEAN fetch() throws JpoException {
        return getExecutionEnvProvider().getSqlExecutor().query(sqlQuery(), sqlValues(), resultSet -> {
            if (resultSet.hasNext()) {
                ResultEntry entry = resultSet.next();
                final Persistor persistor = getExecutionEnvProvider().getOrmClassTool().getPersistor();
                BeanFromResultSet beanFromRS = persistor.beanFromResultSet(entry, getExecutionEnvProvider().getIgnoredFields());
                return beanFromRS.getBean();
            }
            return null;
        });
    }

    /**
     * Execute the query and for each bean returned the callback method of
     * {@link RowMapper} is called. No references to created Beans are hold by
     * the orm; in addition, one bean at time is created just before calling the
     * callback method. This method permits to handle big amount of data with a
     * minimum memory footprint.
     *
     * @param orm
     * @throws JpoException
     */
    public default void fetch(final BiConsumer beanReader) throws JpoException {
        final Persistor persistor = getExecutionEnvProvider().getOrmClassTool().getPersistor();
        List ignoredFields = getExecutionEnvProvider().getIgnoredFields();
        getExecutionEnvProvider().getSqlExecutor().query(sqlQuery(), sqlValues(), (entry, rowCount) -> {
            BeanFromResultSet beanFromRS = persistor.beanFromResultSet(entry, ignoredFields);
            beanReader.accept(beanFromRS.getBean(), rowCount);
        });
    }

    /**
     * Execute the query and for each bean returned the callback method of
     * {@link RowMapper} is called. No references to created Beans are hold by
     * the orm; in addition, one bean at time is created just before calling the
     * callback method. This method permits to handle big amount of data with a
     * minimum memory footprint.
     *
     * @param orm
     * @throws JpoException
     */
    public default  List fetch(final BiFunction beanReader) throws JpoException {
        final Persistor persistor = getExecutionEnvProvider().getOrmClassTool().getPersistor();
        List ignoredFields = getExecutionEnvProvider().getIgnoredFields();
        return getExecutionEnvProvider().getSqlExecutor().query(sqlQuery(), sqlValues(), (resultEntry, rowCount) -> {
                BeanFromResultSet beanFromRS = persistor.beanFromResultSet(resultEntry, ignoredFields);
                return beanReader.apply(beanFromRS.getBean(), rowCount);
        });
    }

    /**
     * Execute the query returning the list of beans.
     *
     * @return
     */
    public default List fetchList() {
        return fetch((final BEAN newObject, final Integer rowCount) -> {
            return newObject;
        });
    }

    /**
     * Fetch the bean
     *
     * @return
     */
    public default Optional fetchOptional() throws JpoException {
        return Optional.ofNullable(fetch());
    }

    /**
     * Return the count of entities this query should return.
     *
     * @return
     */
    public default int fetchRowCount() {
        return getExecutionEnvProvider().getSqlExecutor().queryForIntUnique(sqlRowCountQuery(), sqlValues());
    }

    /**
     * Fetch the bean. An {@link JpoNotUniqueResultException} is thrown if the
     * result is not unique.
     *
     * @return
     */
    public default BEAN fetchUnique() throws JpoNotUniqueResultException {
        final GenericWrapper wrapper = new GenericWrapper<>(null);
        fetch((final BEAN newObject, final Integer rowCount) -> {
            if (rowCount > 0) {
                throw new JpoNotUniqueResultManyResultsException(
                        "The query execution returned a number of rows different than one: more than one result found");
            }
            wrapper.setValue(newObject);
        });
        if (wrapper.getValue() == null) {
            throw new JpoNotUniqueResultNoResultException("The query execution returned a number of rows different than one: no results found");
        }
        return wrapper.getValue();
    }

    /**
     * Return whether at least one entries exists that matches the query. It is
     * equivalent to fetchRowCount()>0
     *
     * @return
     */
    public default boolean exist() {
        return fetchRowCount() > 0;
    }

    ExecutionEnvProvider getExecutionEnvProvider();

}