137 lines
4.0 KiB
Java
137 lines
4.0 KiB
Java
/**
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* Copyright (c) 2011-2017, 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.math.BigDecimal;
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import com.jfinal.template.TemplateException;
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import com.jfinal.template.expr.Sym;
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import com.jfinal.template.stat.Location;
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import com.jfinal.template.stat.ParseException;
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import com.jfinal.template.stat.Scope;
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/**
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* unary : ('!' | '+' | '-'| '++' | '--') expr
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*
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* 只支持 +expr 与 -expr
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* !expr、 ++expr、 --expr 分别由 Logic、IncDec 支持
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*/
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public class Unary extends Expr {
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private Sym op;
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private Expr expr;
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public Unary(Sym op, Expr expr, Location location) {
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if (expr == null) {
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throw new ParseException("The parameter of \"" + op.value() + "\" operator can not be blank", location);
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}
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this.op = op;
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this.expr = expr;
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this.location = location;
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}
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/**
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* unary : ('!' | '+' | '-'| '++' | '--') expr
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*/
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public Object eval(Scope scope) {
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Object value = expr.eval(scope);
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if (value == null) {
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if (scope.getCtrl().isNullSafe()) {
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return null;
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}
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throw new TemplateException("The parameter of \"" + op.value() + "\" operator can not be blank", location);
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}
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if (! (value instanceof Number) ) {
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throw new TemplateException(op.value() + " operator only support int long float double BigDecimal type", location);
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}
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switch (op) {
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case ADD:
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return value;
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case SUB:
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Number n = (Number)value;
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if (n instanceof Integer) {
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return Integer.valueOf(-n.intValue());
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}
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if (n instanceof Long) {
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return Long.valueOf(-n.longValue());
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}
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if (n instanceof Float) {
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return Float.valueOf(-n.floatValue());
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}
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if (n instanceof Double) {
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return Double.valueOf(-n.doubleValue());
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}
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if (n instanceof BigDecimal) {
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return ((BigDecimal)n).negate();
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}
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throw new TemplateException("Unsupported data type: " + n.getClass().getName(), location);
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default :
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throw new TemplateException("Unsupported operator: " + op.value(), location);
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}
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}
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/**
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* 如果可能的话，将 Unary 表达式转化成 Const 表达式，类似于 ExprParser.buildMapEntry() 需要这种转化来简化实现
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* 除了可简化程序外，还起到一定的性能优化作用
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*
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* Number : +123 -456 +3.14 -0.12
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* Boolean : !true !false
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*
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* 特别注意：
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* Boolean 的支持并不需要，!true、!false 已在 ExprParser 中被 Logic 表达式接管，在此仅为逻辑上的完备性而添加
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*/
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public Expr toConstIfPossible() {
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if (expr instanceof Const && (op == Sym.SUB || op == Sym.ADD || op == Sym.NOT)) {
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} else {
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return this;
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}
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Expr ret = this;
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Const c = (Const)expr;
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if (op == Sym.SUB) {
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if (c.isInt()) {
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ret = new Const(Sym.INT, -c.getInt());
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} else if (c.isLong()) {
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ret = new Const(Sym.LONG, -c.getLong());
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} else if (c.isFloat()) {
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ret = new Const(Sym.FLOAT, -c.getFloat());
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} else if (c.isDouble()) {
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ret = new Const(Sym.DOUBLE, -c.getDouble());
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}
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} else if (op == Sym.ADD) {
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if (c.isNumber()) {
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ret = c;
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}
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} else if (op == Sym.NOT) {
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if (c.isBoolean()) {
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ret = c.isTrue() ? Const.FALSE : Const.TRUE;
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}
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}
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return ret;
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}
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public String toString() {
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return op.toString() + expr.toString();
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}
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}
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