com.jn.sqlhelper.dialect.internal.AuroraDialect Maven / Gradle / Ivy

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/*
 * Copyright 2019 the original author or authors.
 *
 * Licensed under the LGPL, Version 3.0 (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.gnu.org/licenses/lgpl-3.0.html
 *
 * 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.jn.sqlhelper.dialect.internal;

import com.jn.langx.util.ClassLoaders;
import com.jn.sqlhelper.dialect.likeescaper.LikeEscaper;
import com.jn.sqlhelper.dialect.internal.limit.LimitCommaLimitHandler;
import com.jn.sqlhelper.dialect.internal.limit.LimitHandler;
import com.jn.sqlhelper.dialect.internal.limit.LimitOffsetLimitHandler;

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

/**
 * Amazon Aurora
 */
public class AuroraDialect extends AbstractDialect {
    enum WorkingWith {
        MySQL,
        PostgreSQL
    }

    private WorkingWith workingWith;

    private static final Map limitHandlerMap = new HashMap();
    private static final Map likeEscaperMap = new HashMap();

    static {
        limitHandlerMap.put(WorkingWith.MySQL, new LimitCommaLimitHandler());
        limitHandlerMap.put(WorkingWith.PostgreSQL, new LimitOffsetLimitHandler());
    }

    public AuroraDialect() {
        super();
        if (findMySQLDriver()) {
            workingWith = WorkingWith.MySQL;
        } else if (findPostgreSQLDriver()) {
            workingWith = WorkingWith.PostgreSQL;
        }
        if(workingWith==null){
            workingWith=WorkingWith.MySQL;
        }
        setLimitHandler(limitHandlerMap.get(workingWith));
    }

    private static boolean findMySQLDriver() {
        return ClassLoaders.hasClass("com.mysql.jdbc.Driver", AuroraDialect.class.getClassLoader()) || ClassLoaders.hasClass("com.mysql.cj.jdbc.Driver", AuroraDialect.class.getClassLoader()) ;
    }

    private static boolean findPostgreSQLDriver() {
        return ClassLoaders.hasClass("org.postgresql.Driver", AuroraDialect.class.getClassLoader());
    }

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

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

    @Override
    public boolean isBindLimitParametersInReverseOrder() {
        boolean reverse = false;
        switch (workingWith) {
            case MySQL:
                reverse = false;
                break;
            case PostgreSQL:
                reverse = true;
                break;
            default:
                reverse = false;
                break;
        }
        return reverse;
    }
}