org.springframework.jdbc.support.JdbcAccessor.java Source code

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Here is the source code for org.springframework.jdbc.support.JdbcAccessor.java

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/*
 * Copyright 2002-2018 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
 *
 *      https://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.jdbc.support;

import javax.sql.DataSource;

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

import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Base class for {@link org.springframework.jdbc.core.JdbcTemplate} and
 * other JDBC-accessing DAO helpers, defining common properties such as
 * DataSource and exception translator.
 *
 * <p>Not intended to be used directly.
 * See {@link org.springframework.jdbc.core.JdbcTemplate}.
 *
 * @author Juergen Hoeller
 * @since 28.11.2003
 * @see org.springframework.jdbc.core.JdbcTemplate
 */
public abstract class JdbcAccessor implements InitializingBean {

    /** Logger available to subclasses. */
    protected final Log logger = LogFactory.getLog(getClass());

    @Nullable
    private DataSource dataSource;

    @Nullable
    private volatile SQLExceptionTranslator exceptionTranslator;

    private boolean lazyInit = true;

    /**
     * Set the JDBC DataSource to obtain connections from.
     */
    public void setDataSource(@Nullable DataSource dataSource) {
        this.dataSource = dataSource;
    }

    /**
     * Return the DataSource used by this template.
     */
    @Nullable
    public DataSource getDataSource() {
        return this.dataSource;
    }

    /**
     * Obtain the DataSource for actual use.
     * @return the DataSource (never {@code null})
     * @throws IllegalStateException in case of no DataSource set
     * @since 5.0
     */
    protected DataSource obtainDataSource() {
        DataSource dataSource = getDataSource();
        Assert.state(dataSource != null, "No DataSource set");
        return dataSource;
    }

    /**
     * Specify the database product name for the DataSource that this accessor uses.
     * This allows to initialize a SQLErrorCodeSQLExceptionTranslator without
     * obtaining a Connection from the DataSource to get the meta-data.
     * @param dbName the database product name that identifies the error codes entry
     * @see SQLErrorCodeSQLExceptionTranslator#setDatabaseProductName
     * @see java.sql.DatabaseMetaData#getDatabaseProductName()
     */
    public void setDatabaseProductName(String dbName) {
        this.exceptionTranslator = new SQLErrorCodeSQLExceptionTranslator(dbName);
    }

    /**
     * Set the exception translator for this instance.
     * <p>If no custom translator is provided, a default
     * {@link SQLErrorCodeSQLExceptionTranslator} is used
     * which examines the SQLException's vendor-specific error code.
     * @see org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator
     * @see org.springframework.jdbc.support.SQLStateSQLExceptionTranslator
     */
    public void setExceptionTranslator(SQLExceptionTranslator exceptionTranslator) {
        this.exceptionTranslator = exceptionTranslator;
    }

    /**
     * Return the exception translator for this instance.
     * <p>Creates a default {@link SQLErrorCodeSQLExceptionTranslator}
     * for the specified DataSource if none set, or a
     * {@link SQLStateSQLExceptionTranslator} in case of no DataSource.
     * @see #getDataSource()
     */
    public SQLExceptionTranslator getExceptionTranslator() {
        SQLExceptionTranslator exceptionTranslator = this.exceptionTranslator;
        if (exceptionTranslator != null) {
            return exceptionTranslator;
        }
        synchronized (this) {
            exceptionTranslator = this.exceptionTranslator;
            if (exceptionTranslator == null) {
                DataSource dataSource = getDataSource();
                if (dataSource != null) {
                    exceptionTranslator = new SQLErrorCodeSQLExceptionTranslator(dataSource);
                } else {
                    exceptionTranslator = new SQLStateSQLExceptionTranslator();
                }
                this.exceptionTranslator = exceptionTranslator;
            }
            return exceptionTranslator;
        }
    }

    /**
     * Set whether to lazily initialize the SQLExceptionTranslator for this accessor,
     * on first encounter of a SQLException. Default is "true"; can be switched to
     * "false" for initialization on startup.
     * <p>Early initialization just applies if {@code afterPropertiesSet()} is called.
     * @see #getExceptionTranslator()
     * @see #afterPropertiesSet()
     */
    public void setLazyInit(boolean lazyInit) {
        this.lazyInit = lazyInit;
    }

    /**
     * Return whether to lazily initialize the SQLExceptionTranslator for this accessor.
     * @see #getExceptionTranslator()
     */
    public boolean isLazyInit() {
        return this.lazyInit;
    }

    /**
     * Eagerly initialize the exception translator, if demanded,
     * creating a default one for the specified DataSource if none set.
     */
    @Override
    public void afterPropertiesSet() {
        if (getDataSource() == null) {
            throw new IllegalArgumentException("Property 'dataSource' is required");
        }
        if (!isLazyInit()) {
            getExceptionTranslator();
        }
    }

}