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the jfinal enjoy plugin for normal java program to use sql management function.
/**
* Copyright (c) 2011-2017, James Zhan 詹波 ([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.jfinal.template.expr.ast;
import java.math.BigDecimal;
import java.math.RoundingMode;
import com.jfinal.template.TemplateException;
import com.jfinal.template.expr.Sym;
import com.jfinal.template.stat.Location;
import com.jfinal.template.stat.ParseException;
import com.jfinal.template.stat.Scope;
/**
* Arithmetic
* 1：支持 byte short int long float double BigDecimal 的 + - * / % 运算
* 2：支持字符串加法运算
*/
public class Arith extends Expr {
public static final int INT = 0; // byte、short 用 int 类型支持，java 表达式亦如此
public static final int LONG = 1;
public static final int FLOAT = 2;
public static final int DOUBLE = 3;
public static final int BIGDECIMAL = 4;
private Sym op;
private Expr left;
private Expr right;
public Arith(Sym op, Expr left, Expr right, Location location) {
if (left == null || right == null) {
throw new ParseException("The target of \"" + op.value() + "\" operator can not be blank", location);
}
this.op = op;
this.left = left;
this.right = right;
this.location = location;
}
public Object eval(Scope scope) {
try {
return doEval(scope);
} catch (TemplateException e) {
throw e;
} catch (Exception e) {
throw new TemplateException(e.getMessage(), location, e);
}
}
private Object doEval(Scope scope) {
Object leftValue = left.eval(scope);
Object rightValue = right.eval(scope);
if (leftValue instanceof Number && rightValue instanceof Number) {
Number l = (Number)leftValue;
Number r = (Number)rightValue;
int maxType = getMaxType(l, r);
switch (op) {
case ADD:
return add(maxType, l, r);
case SUB:
return sub(maxType, l, r);
case MUL:
return mul(maxType, l, r);
case DIV:
return div(maxType, l, r);
case MOD:
return mod(maxType, l, r);
default :
throw new TemplateException("Unsupported operator: " + op.value(), location);
}
}
// 字符串加法运算
if (leftValue instanceof String || rightValue instanceof String) {
return String.valueOf(leftValue).concat(String.valueOf(rightValue));
}
String leftObj = leftValue != null ? leftValue.getClass().getName() : "null";
String rightObj = rightValue != null ? rightValue.getClass().getName() : "null";
throw new TemplateException("Unsupported operation type: " + leftObj + " " + op.value() + " " + rightObj, location);
}
private int getMaxType(Number obj1, Number obj2) {
int t1 = getType(obj1);
if (t1 == BIGDECIMAL) {
return BIGDECIMAL;
}
int t2 = getType(obj2);
return t1 > t2 ? t1 : t2;
}
/**
* 注意：调用此方法的前提是，其中有一个对象的类型已经确定是 BigDecimal
*/
private BigDecimal[] toBigDecimals(Number left, Number right) {
BigDecimal[] ret = new BigDecimal[2];
if (left instanceof BigDecimal) {
ret[0] = (BigDecimal)left;
ret[1] = new BigDecimal(right.toString());
} else {
ret[0] = new BigDecimal(left.toString());
ret[1] = (BigDecimal)right;
}
return ret;
}
private int getType(Number obj) {
if (obj instanceof Integer) {
return INT;
} else if (obj instanceof Long) {
return LONG;
} else if (obj instanceof Float) {
return FLOAT;
} else if (obj instanceof Double) {
return DOUBLE;
} else if (obj instanceof BigDecimal) {
return BIGDECIMAL;
} else if (obj instanceof Short || obj instanceof Byte) {
return INT; // short byte 用 int 支持，java 表达式亦如此
}
throw new TemplateException("Unsupported data type: " + obj.getClass().getName(), location);
}
private Number add(int maxType, Number left, Number right) {
switch (maxType) {
case INT:
return Integer.valueOf(left.intValue() + right.intValue());
case LONG:
return Long.valueOf(left.longValue() + right.longValue());
case FLOAT:
return Float.valueOf(left.floatValue() + right.floatValue());
case DOUBLE:
return Double.valueOf(left.doubleValue() + right.doubleValue());
case BIGDECIMAL:
BigDecimal[] bd = toBigDecimals(left, right);
return (bd[0]).add(bd[1]);
}
throw new TemplateException("Unsupported data type", location);
}
private Number sub(int maxType, Number left, Number right) {
switch (maxType) {
case INT:
return Integer.valueOf(left.intValue() - right.intValue());
case LONG:
return Long.valueOf(left.longValue() - right.longValue());
case FLOAT:
return Float.valueOf(left.floatValue() - right.floatValue());
case DOUBLE:
return Double.valueOf(left.doubleValue() - right.doubleValue());
case BIGDECIMAL:
BigDecimal[] bd = toBigDecimals(left, right);
return (bd[0]).subtract(bd[1]);
}
throw new TemplateException("Unsupported data type", location);
}
private Number mul(int maxType, Number left, Number right) {
switch (maxType) {
case INT:
return Integer.valueOf(left.intValue() * right.intValue());
case LONG:
return Long.valueOf(left.longValue() * right.longValue());
case FLOAT:
return Float.valueOf(left.floatValue() * right.floatValue());
case DOUBLE:
return Double.valueOf(left.doubleValue() * right.doubleValue());
case BIGDECIMAL:
BigDecimal[] bd = toBigDecimals(left, right);
return (bd[0]).multiply(bd[1]);
}
throw new TemplateException("Unsupported data type", location);
}
private Number div(int maxType, Number left, Number right) {
switch (maxType) {
case INT:
return Integer.valueOf(left.intValue() / right.intValue());
case LONG:
return Long.valueOf(left.longValue() / right.longValue());
case FLOAT:
return Float.valueOf(left.floatValue() / right.floatValue());
case DOUBLE:
return Double.valueOf(left.doubleValue() / right.doubleValue());
case BIGDECIMAL:
BigDecimal[] bd = toBigDecimals(left, right);
// return (bd[0]).divide(bd[1]);
return (bd[0]).divide(bd[1], RoundingMode.HALF_EVEN); // 银行家舍入法
}
throw new TemplateException("Unsupported data type", location);
}
private Number mod(int maxType, Number left, Number right) {
switch (maxType) {
case INT:
return Integer.valueOf(left.intValue() % right.intValue());
case LONG:
return Long.valueOf(left.longValue() % right.longValue());
case FLOAT:
return Float.valueOf(left.floatValue() % right.floatValue());
case DOUBLE:
return Double.valueOf(left.doubleValue() % right.doubleValue());
case BIGDECIMAL:
BigDecimal[] bd = toBigDecimals(left, right);
return (bd[0]).divideAndRemainder(bd[1])[1];
}
throw new TemplateException("Unsupported data type", location);
}
}