org.springframework.xd.jdbc.NamedColumnJdbcItemReaderFactory.java Source code

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Here is the source code for org.springframework.xd.jdbc.NamedColumnJdbcItemReaderFactory.java

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/*
 * Copyright 2014 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.springframework.xd.jdbc;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.batch.item.database.AbstractCursorItemReader;
import org.springframework.batch.support.DatabaseType;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Factory for configuring a {@link org.springframework.xd.jdbc.NamedColumnJdbcItemReader}.  This factory
 * will verify the type of database and configure the appropriate properties so that a streaming cursor is
 * returned.  Specifically, it will configure {@code fetchSize=Integer.MIN_VALUE} for MySql and set
 * {@code verifyCursorPosition=false } for both MySql and SQLite.
 *
 * @author Michael Minella
 * @author Thomas Risberg
 */
public class NamedColumnJdbcItemReaderFactory implements FactoryBean<NamedColumnJdbcItemReader>, InitializingBean {

    private static final Log log = LogFactory.getLog(NamedColumnJdbcItemReaderFactory.class);

    private DataSource dataSource;

    private String tableName;

    private String columnNames;

    private String partitionClause;

    private String sql;

    private int fetchSize;

    private boolean verifyCursorPosition = true;

    private boolean initialized = false;

    private NamedColumnJdbcItemReader reader;

    @Override
    public NamedColumnJdbcItemReader getObject() throws Exception {

        if (!initialized) {
            throw new IllegalStateException("Properties have not been initalized");
        }
        return reader;
    }

    @Override
    public Class<?> getObjectType() {
        return NamedColumnJdbcItemReader.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        if (!StringUtils.hasText(sql)) {
            Assert.hasText(tableName, "tableName must be set");
            Assert.hasText(columnNames, "columns must be set");

            String sql;
            if (StringUtils.hasText(partitionClause)) {
                sql = "SELECT " + columnNames + " FROM " + tableName + " " + partitionClause;
            } else {
                sql = "SELECT " + columnNames + " FROM " + tableName;
            }
            log.info("Setting SQL to: " + sql);
            setSql(sql);
        } else if (StringUtils.hasText(columnNames) || StringUtils.hasText(tableName)) {
            log.warn("You must set either the 'sql' property or 'tableName' and 'columns'.");
        }

        DatabaseType type = DatabaseType.fromMetaData(dataSource);

        switch (type) {
        case MYSQL:
            fetchSize = Integer.MIN_VALUE;
            // MySql doesn't support getRow for a streaming cursor
            verifyCursorPosition = false;
            break;
        case SQLITE:
            fetchSize = AbstractCursorItemReader.VALUE_NOT_SET;
            break;
        default:
            // keep configured fetchSize
        }

        reader = new NamedColumnJdbcItemReader();
        reader.setSql(sql);
        reader.setFetchSize(fetchSize);
        reader.setDataSource(dataSource);
        reader.setVerifyCursorPosition(verifyCursorPosition);
        reader.afterPropertiesSet();

        initialized = true;
    }

    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public void setTableName(String tableName) {
        this.tableName = tableName;
    }

    public void setColumnNames(String columnNames) {
        this.columnNames = columnNames;
    }

    public void setPartitionClause(String partitionClause) {
        this.partitionClause = partitionClause;
    }

    public void setSql(String sql) {
        this.sql = sql;
    }

    public void setFetchSize(int fetchSize) {
        this.fetchSize = fetchSize;
    }

    public void setVerifyCursorPosition(boolean verify) {
        this.verifyCursorPosition = verify;
    }

}