74 lines
2.4 KiB
Java
74 lines
2.4 KiB
Java
/**
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* Copyright (c) 2011-2019, James Zhan 詹波 (jfinal@126.com).
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.jfinal.template.expr.ast;
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import java.util.LinkedHashMap;
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import java.util.Map.Entry;
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import com.jfinal.template.stat.Scope;
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/**
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* Map
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*
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* 1：定义 map 常量
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* {k1:123, k2:"abc", 'k3':true, "k4":[1,2,3], k5:1+2, 1:12, true:"Y", null:"abc"}
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* 如上所示，map定义的 key 可以为 id 标识符或者 String、Integer、Long、Boolean、null
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* 等常量值 (详见 ExprParser.buildMapEntry(...) 方法)，
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* 右侧的 value 可以是任意的常量与表达式
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*
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* 2：取值
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* 先将 Map 常量赋值给某个变量： #set(map = {...})
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* map['k1']
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* map["k1"]
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* map[expr]
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* map.get("k1")
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* map.k1
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*
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* 3：不通过中间变量取值
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* {1:'自买', 2:'跟买'}.get(1)
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* {1:'自买', 2:'跟买'}[2]
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*
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* 如上所示，当以下标方式取值时，下标参数可以是 string 与 expr，而 expr 求值以后的值必须也为 string类型
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* 当用 map.k1 这类 field 字段取值形式时，则是使用 id 标识符，而不是 string 形参数
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*
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* 注意：即便是定义的时候 key 用的是 id 标识符，但在取值时也要用 string 类型下标参数或 expr 求值后为 string
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* 定义时 key 可以使用 id 标识符是为了书写方便，本质上仍然是 string
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*
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* 3：可创建空 map，如： #(map = {})
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*/
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public class Map extends Expr {
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private LinkedHashMap<Object, Expr> map;
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public Map(LinkedHashMap<Object, Expr> map) {
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this.map = map;
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}
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public Object eval(Scope scope) {
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LinkedHashMap<Object, Object> valueMap = new LinkedHashMap<Object, Object>(map.size());
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for (Entry<Object, Expr> e : map.entrySet()) {
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valueMap.put(e.getKey(), e.getValue().eval(scope));
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}
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return valueMap;
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}
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}
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