org.mybatis.spring.batch.MyBatisCursorItemReader.java Source code

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Here is the source code for org.mybatis.spring.batch.MyBatisCursorItemReader.java

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/**
 *    Copyright 2010-2016 the original author or authors.
 *
 *    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.mybatis.spring.batch;

import static org.springframework.util.Assert.notNull;
import static org.springframework.util.ClassUtils.getShortName;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.apache.ibatis.cursor.Cursor;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader;
import org.springframework.beans.factory.InitializingBean;

/**
 * @author Guillaume Darmont / guillaume@dropinocean.com
 */
public class MyBatisCursorItemReader<T> extends AbstractItemCountingItemStreamItemReader<T>
        implements InitializingBean {

    private String queryId;

    private SqlSessionFactory sqlSessionFactory;
    private SqlSession sqlSession;

    private Map<String, Object> parameterValues;

    private Cursor<T> cursor;
    private Iterator<T> cursorIterator;

    public MyBatisCursorItemReader() {
        setName(getShortName(MyBatisCursorItemReader.class));
    }

    @Override
    protected T doRead() throws Exception {
        T next = null;
        if (cursorIterator.hasNext()) {
            next = cursorIterator.next();
        }
        return next;
    }

    @Override
    protected void doOpen() throws Exception {
        Map<String, Object> parameters = new HashMap<String, Object>();
        if (parameterValues != null) {
            parameters.putAll(parameterValues);
        }

        sqlSession = sqlSessionFactory.openSession(ExecutorType.SIMPLE);
        cursor = sqlSession.selectCursor(queryId, parameters);
        cursorIterator = cursor.iterator();
    }

    @Override
    protected void doClose() throws Exception {
        cursor.close();
        sqlSession.close();
        cursorIterator = null;
    }

    /**
     * Check mandatory properties.
     *
     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
     */
    @Override
    public void afterPropertiesSet() throws Exception {
        notNull(sqlSessionFactory);
        notNull(queryId);
    }

    /**
     * Public setter for {@link SqlSessionFactory} for injection purposes.
     *
     * @param sqlSessionFactory a factory object for the {@link SqlSession}.
     */
    public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;
    }

    /**
     * Public setter for the statement id identifying the statement in the SqlMap
     * configuration file.
     *
     * @param queryId the id for the statement
     */
    public void setQueryId(String queryId) {
        this.queryId = queryId;
    }

    /**
     * The parameter values to be used for the query execution.
     *
     * @param parameterValues the values keyed by the parameter named used in
     *                        the query string.
     */
    public void setParameterValues(Map<String, Object> parameterValues) {
        this.parameterValues = parameterValues;
    }
}