PageAutoDialect.java

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2023 abel533@gmail.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
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 * The above copyright notice and this permission notice shall be included in
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package com.github.pagehelper.page;

import com.github.pagehelper.AutoDialect;
import com.github.pagehelper.Dialect;
import com.github.pagehelper.PageException;
import com.github.pagehelper.dialect.AbstractHelperDialect;
import com.github.pagehelper.dialect.auto.*;
import com.github.pagehelper.dialect.helper.*;
import com.github.pagehelper.util.ClassUtil;
import com.github.pagehelper.util.StringUtil;
import org.apache.ibatis.mapping.MappedStatement;

import javax.sql.DataSource;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 基础方言信息
 *
 * @author liuzh
 */
public class PageAutoDialect {

    private static Map<String, Class<? extends Dialect>>     dialectAliasMap = new LinkedHashMap<>();
    private static Map<String, Class<? extends AutoDialect>> autoDialectMap  = new LinkedHashMap<>();

    public static void registerDialectAlias(String alias, Class<? extends Dialect> dialectClass) {
        dialectAliasMap.put(alias, dialectClass);
    }

    static {
        //注册别名
        registerDialectAlias("hsqldb", HsqldbDialect.class);
        registerDialectAlias("h2", HsqldbDialect.class);
        registerDialectAlias("phoenix", HsqldbDialect.class);

        registerDialectAlias("postgresql", PostgreSqlDialect.class);

        registerDialectAlias("mysql", MySqlDialect.class);
        registerDialectAlias("mariadb", MySqlDialect.class);
        registerDialectAlias("sqlite", MySqlDialect.class);

        registerDialectAlias("herddb", HerdDBDialect.class);

        registerDialectAlias("oracle", OracleDialect.class);
        registerDialectAlias("oracle9i", Oracle9iDialect.class);
        registerDialectAlias("db2", Db2Dialect.class);
        registerDialectAlias("as400", AS400Dialect.class);
        registerDialectAlias("informix", InformixDialect.class);
        //解决 informix-sqli #129，仍然保留上面的
        registerDialectAlias("informix-sqli", InformixDialect.class);

        registerDialectAlias("sqlserver", SqlServerDialect.class);
        registerDialectAlias("sqlserver2012", SqlServer2012Dialect.class);

        registerDialectAlias("derby", SqlServer2012Dialect.class);
        //达梦数据库,https://github.com/mybatis-book/book/issues/43
        registerDialectAlias("dm", OracleDialect.class);
        //阿里云PPAS数据库,https://github.com/pagehelper/Mybatis-PageHelper/issues/281
        registerDialectAlias("edb", OracleDialect.class);
        //神通数据库
        registerDialectAlias("oscar", OscarDialect.class);
        registerDialectAlias("clickhouse", MySqlDialect.class);
        //瀚高数据库
        registerDialectAlias("highgo", HsqldbDialect.class);
        //虚谷数据库
        registerDialectAlias("xugu", HsqldbDialect.class);
        registerDialectAlias("impala", HsqldbDialect.class);
        registerDialectAlias("firebirdsql", FirebirdDialect.class);
        //人大金仓数据库
        registerDialectAlias("kingbase", PostgreSqlDialect.class);
        // 人大金仓新版本kingbase8
        registerDialectAlias("kingbase8", PostgreSqlDialect.class);
        //行云数据库
        registerDialectAlias("xcloud", CirroDataDialect.class);

        //openGauss数据库
        registerDialectAlias("opengauss", PostgreSqlDialect.class);

        //注册 AutoDialect
        //想要实现和以前版本相同的效果时，可以配置 autoDialectClass=old
        registerAutoDialectAlias("old", DefaultAutoDialect.class);
        registerAutoDialectAlias("hikari", HikariAutoDialect.class);
        registerAutoDialectAlias("druid", DruidAutoDialect.class);
        registerAutoDialectAlias("tomcat-jdbc", TomcatAutoDialect.class);
        registerAutoDialectAlias("dbcp", DbcpAutoDialect.class);
        registerAutoDialectAlias("c3p0", C3P0AutoDialect.class);
        //不配置时，默认使用 DataSourceNegotiationAutoDialect
        registerAutoDialectAlias("default", DataSourceNegotiationAutoDialect.class);
    }

    public static void registerAutoDialectAlias(String alias, Class<? extends AutoDialect> autoDialectClass) {
        autoDialectMap.put(alias, autoDialectClass);
    }

    /**
     * 自动获取dialect,如果没有setProperties或setSqlUtilConfig，也可以正常进行
     */
    private boolean                            autoDialect        = true;
    /**
     * 属性配置
     */
    private Properties                         properties;
    /**
     * 缓存 dialect 实现，key 有两种，分别为 jdbcurl 和 dialectClassName
     */
    private Map<Object, AbstractHelperDialect> urlDialectMap      = new ConcurrentHashMap<Object, AbstractHelperDialect>();
    private ReentrantLock                      lock               = new ReentrantLock();
    private AbstractHelperDialect              delegate;
    private ThreadLocal<AbstractHelperDialect> dialectThreadLocal = new ThreadLocal<AbstractHelperDialect>();
    private AutoDialect                        autoDialectDelegate;

    public static String fromJdbcUrl(String jdbcUrl) {
        final String url = jdbcUrl.toLowerCase();
        for (String dialect : dialectAliasMap.keySet()) {
            if (url.contains(":" + dialect.toLowerCase() + ":")) {
                return dialect;
            }
        }
        return null;
    }

    //获取当前的代理对象
    public AbstractHelperDialect getDelegate() {
        if (delegate != null) {
            return delegate;
        }
        return dialectThreadLocal.get();
    }

    //移除代理对象
    public void clearDelegate() {
        dialectThreadLocal.remove();
    }

    public AbstractHelperDialect getDialectThreadLocal() {
        return dialectThreadLocal.get();
    }

    public void setDialectThreadLocal(AbstractHelperDialect delegate) {
        this.dialectThreadLocal.set(delegate);
    }

    /**
     * 反射类
     *
     * @param className
     * @return
     * @throws Exception
     */
    public static Class resloveDialectClass(String className) throws Exception {
        if (dialectAliasMap.containsKey(className.toLowerCase())) {
            return dialectAliasMap.get(className.toLowerCase());
        } else {
            return Class.forName(className);
        }
    }

    /**
     * 初始化 helper
     *
     * @param dialectClass
     * @param properties
     */
    public static AbstractHelperDialect instanceDialect(String dialectClass, Properties properties) {
        AbstractHelperDialect dialect;
        if (StringUtil.isEmpty(dialectClass)) {
            throw new PageException("When you use the PageHelper pagination plugin, you must set the helper property");
        }
        try {
            Class sqlDialectClass = resloveDialectClass(dialectClass);
            if (AbstractHelperDialect.class.isAssignableFrom(sqlDialectClass)) {
                dialect = (AbstractHelperDialect) sqlDialectClass.newInstance();
            } else {
                throw new PageException("When using PageHelper, the dialect must be an implementation class that implements the " + AbstractHelperDialect.class.getCanonicalName() + " interface!");
            }
        } catch (Exception e) {
            throw new PageException("error initializing helper dialectclass[" + dialectClass + "]" + e.getMessage(), e);
        }
        dialect.setProperties(properties);
        return dialect;
    }

    /**
     * 多数据动态获取时，每次需要初始化，还可以运行时指定具体的实现
     *
     * @param ms
     * @param dialectClass 分页实现，必须是 {@link AbstractHelperDialect} 实现类，可以使用当前类中注册的别名，例如 "mysql", "oracle"
     */
    public void initDelegateDialect(MappedStatement ms, String dialectClass) {
        if (StringUtil.isNotEmpty(dialectClass)) {
            AbstractHelperDialect dialect = urlDialectMap.get(dialectClass);
            if (dialect == null) {
                lock.lock();
                try {
                    if ((dialect = urlDialectMap.get(dialectClass)) == null) {
                        dialect = instanceDialect(dialectClass, properties);
                        urlDialectMap.put(dialectClass, dialect);
                    }
                } finally {
                    lock.unlock();
                }
            }
            dialectThreadLocal.set(dialect);
        } else if (delegate == null) {
            if (autoDialect) {
                this.delegate = autoGetDialect(ms);
            } else {
                dialectThreadLocal.set(autoGetDialect(ms));
            }
        }
    }

    /**
     * 自动获取分页方言实现
     *
     * @param ms
     * @return
     */
    public AbstractHelperDialect autoGetDialect(MappedStatement ms) {
        DataSource dataSource = ms.getConfiguration().getEnvironment().getDataSource();
        Object dialectKey = autoDialectDelegate.extractDialectKey(ms, dataSource, properties);
        if (dialectKey == null) {
            return autoDialectDelegate.extractDialect(dialectKey, ms, dataSource, properties);
        } else if (!urlDialectMap.containsKey(dialectKey)) {
            lock.lock();
            try {
                if (!urlDialectMap.containsKey(dialectKey)) {
                    urlDialectMap.put(dialectKey, autoDialectDelegate.extractDialect(dialectKey, ms, dataSource, properties));
                }
            } finally {
                lock.unlock();
            }
        }
        return urlDialectMap.get(dialectKey);
    }

    /**
     * 初始化自定义 AutoDialect
     *
     * @param properties
     */
    private void initAutoDialectClass(Properties properties) {
        String autoDialectClassStr = properties.getProperty("autoDialectClass");
        if (StringUtil.isNotEmpty(autoDialectClassStr)) {
            try {
                Class<? extends AutoDialect> autoDialectClass;
                if (autoDialectMap.containsKey(autoDialectClassStr)) {
                    autoDialectClass = autoDialectMap.get(autoDialectClassStr);
                } else {
                    autoDialectClass = (Class<AutoDialect>) Class.forName(autoDialectClassStr);
                }
                this.autoDialectDelegate = ClassUtil.newInstance(autoDialectClass, properties);
            } catch (ClassNotFoundException e) {
                throw new IllegalArgumentException("Make sure that the AutoDialect implementation class ("
                        + autoDialectClassStr + ") for the autoDialectClass configuration exists!", e);
            } catch (Exception e) {
                throw new RuntimeException(autoDialectClassStr + "Class must provide a constructor without parameters", e);
            }
        } else {
            this.autoDialectDelegate = new DataSourceNegotiationAutoDialect();
        }
    }

    /**
     * 初始化方言别名
     *
     * @param properties
     */
    private void initDialectAlias(Properties properties) {
        String dialectAlias = properties.getProperty("dialectAlias");
        if (StringUtil.isNotEmpty(dialectAlias)) {
            String[] alias = dialectAlias.split(";");
            for (int i = 0; i < alias.length; i++) {
                String[] kv = alias[i].split("=");
                if (kv.length != 2) {
                    throw new IllegalArgumentException("dialectAlias parameter misconfigured," +
                            "Please follow alias1=xx.dialectClass; alias2=dialectClass2!");
                }
                for (int j = 0; j < kv.length; j++) {
                    try {
                        //允许配置如 dm=oracle, 直接引用oracle实现
                        if (dialectAliasMap.containsKey(kv[1])) {
                            registerDialectAlias(kv[0], dialectAliasMap.get(kv[1]));
                        } else {
                            Class<? extends Dialect> diallectClass = (Class<? extends Dialect>) Class.forName(kv[1]);
                            //允许覆盖已有的实现
                            registerDialectAlias(kv[0], diallectClass);
                        }
                    } catch (ClassNotFoundException e) {
                        throw new IllegalArgumentException("Make sure the Dialect implementation class configured by dialectAlias exists!", e);
                    }
                }
            }
        }
    }

    public void setProperties(Properties properties) {

        this.properties = properties;
        //初始化自定义AutoDialect
        initAutoDialectClass(properties);
        //使用 sqlserver2012 作为默认分页方式，这种情况在动态数据源时方便使用
        String useSqlserver2012 = properties.getProperty("useSqlserver2012");
        if (StringUtil.isNotEmpty(useSqlserver2012) && Boolean.parseBoolean(useSqlserver2012)) {
            registerDialectAlias("sqlserver", SqlServer2012Dialect.class);
            registerDialectAlias("sqlserver2008", SqlServerDialect.class);
        }
        initDialectAlias(properties);
        //指定的 Helper 数据库方言，和  不同
        String dialect = properties.getProperty("helperDialect");
        //运行时获取数据源
        String runtimeDialect = properties.getProperty("autoRuntimeDialect");
        //1.动态多数据源
        if (StringUtil.isNotEmpty(runtimeDialect) && "TRUE".equalsIgnoreCase(runtimeDialect)) {
            this.autoDialect = false;
        }
        //2.动态获取方言
        else if (StringUtil.isEmpty(dialect)) {
            autoDialect = true;
        }
        //3.指定方言
        else {
            autoDialect = false;
            this.delegate = instanceDialect(dialect, properties);
        }
    }
}