com.baomidou.mybatisplus.extension.kotlin.KtQueryWrapper.kt Maven / Gradle / Ivy

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/*
 * Copyright (c) 2011-2022, baomidou ([email protected]).
 *
 * 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 com.baomidou.mybatisplus.extension.kotlin

import com.baomidou.mybatisplus.core.conditions.SharedString
import com.baomidou.mybatisplus.core.conditions.query.Query
import com.baomidou.mybatisplus.core.conditions.segments.MergeSegments
import com.baomidou.mybatisplus.core.metadata.TableFieldInfo
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper
import com.baomidou.mybatisplus.core.toolkit.ArrayUtils
import com.baomidou.mybatisplus.core.toolkit.support.ColumnCache
import java.util.concurrent.atomic.AtomicInteger
import java.util.function.Predicate
import kotlin.reflect.KProperty

/**
 * Kotlin Lambda 语法使用 Wrapper
 *
 * @author yangyuhan
 * @since 2018-11-02
 */
open class KtQueryWrapper : AbstractKtWrapper>, Query, T, KProperty<*>> {

    /**
     * 查询字段
     */
    private var sqlSelect: SharedString = SharedString()

    constructor(entity: T) {
        this.entity = entity
        super.initNeed()
    }

    constructor(entityClass: Class) {
        this.entityClass = entityClass
        super.initNeed()
    }

    internal constructor(entity: T?, entityClass: Class, sqlSelect: SharedString, paramNameSeq: AtomicInteger,
                         paramNameValuePairs: Map, columnMap: Map,
                         lastSql: SharedString, sqlComment: SharedString, sqlFirst: SharedString) {
        this.entity = entity
        this.paramNameSeq = paramNameSeq
        this.paramNameValuePairs = paramNameValuePairs
        this.expression = MergeSegments()
        this.columnMap = columnMap
        this.sqlSelect = sqlSelect
        this.entityClass = entityClass
        this.lastSql = lastSql
        this.sqlComment = sqlComment
        this.sqlFirst = sqlFirst
    }

    /**
     * SELECT 部分 SQL 设置
     *
     * @param columns 查询字段
     */
    @SafeVarargs
    override fun select(vararg columns: KProperty<*>): KtQueryWrapper {
        if (ArrayUtils.isNotEmpty(columns)) {
            this.sqlSelect.stringValue = columnsToString(false, *columns)
        }
        return typedThis
    }

    /**
     * 过滤查询的字段信息(主键除外!)
     *
     * 例1: 只要 java 字段名以 "test" 开头的              -> select(i -> i.getProperty().startsWith("test"))
     *
     * 例2: 只要 java 字段属性是 CharSequence 类型的       -> select(TableFieldInfo::isCharSequence)
     *
     * 例3: 只要 java 字段没有填充策略的                   -> select(i -> i.getFieldFill == FieldFill.DEFAULT)
     *
     * 例4: 要全部字段                                   -> select(i -> true)
     *
     * 例5: 只要主键字段                                 -> select(i -> false)
     *
     *
     * @param predicate 过滤方式
     * @return this
     */
    override fun select(entityClass: Class, predicate: Predicate): KtQueryWrapper {
        this.entityClass = entityClass
        this.sqlSelect.stringValue = TableInfoHelper.getTableInfo(getEntityClass()).chooseSelect(predicate)
        return typedThis
    }

    override fun getSqlSelect(): String? {
        return sqlSelect.stringValue
    }

    /**
     * 用于生成嵌套 sql
     *
     * 故 sqlSelect 不向下传递
     */
    override fun instance(): KtQueryWrapper {
        return KtQueryWrapper(entity, entityClass, sqlSelect, paramNameSeq, paramNameValuePairs, columnMap,
            SharedString.emptyString(), SharedString.emptyString(), SharedString.emptyString())
    }

    override fun clear() {
        super.clear()
        sqlSelect.toNull()
    }
}