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enjoy/src/main/java/com/jfinal/template/expr/ast/RangeArray.java
2018-04-25 22:09:05 +08:00

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/**
* Copyright (c) 2011-2019, James Zhan 詹波 (jfinal@126.com).
*
* 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.util.AbstractList;
import com.jfinal.template.TemplateException;
import com.jfinal.template.stat.Location;
import com.jfinal.template.stat.ParseException;
import com.jfinal.template.stat.Scope;
/**
* RangeArray : [expr .. expr]
*
* 用法:
* 1[1..3]
* 2[3..1]
*/
public class RangeArray extends Expr {
private Expr start;
private Expr end;
/**
* array : '[' exprList ? | range ? ']'
* exprList : expr (',' expr)*
* range : expr .. expr
*/
public RangeArray(Expr start, Expr end, Location location) {
if (start == null) {
throw new ParseException("The start value of range array can not be blank", location);
}
if (end == null) {
throw new ParseException("The end value of range array can not be blank", location);
}
this.start = start;
this.end = end;
this.location = location;
}
public Object eval(Scope scope) {
Object startValue = start.eval(scope);
if ( !(startValue instanceof Integer) ) {
throw new TemplateException("The start value of range array must be Integer", location);
}
Object endValue = end.eval(scope);
if ( !(endValue instanceof Integer) ) {
throw new TemplateException("The end value of range array must be Integer", location);
}
return new RangeList((Integer)startValue, (Integer)endValue, location);
}
public static class RangeList extends AbstractList<Integer> {
final int start;
final int size;
final int increment;
final Location location;
public RangeList(int start, int end, Location location) {
this.start = start;
this.increment = start <= end ? 1 : -1;
this.size = Math.abs(end - start) + 1;
this.location = location;
}
public Integer get(int index) {
if (index < 0 || index >= size) {
throw new TemplateException("Index out of bounds. Index: " + index + ", Size: " + size, location);
}
return start + index * increment;
}
public int size() {
return size;
}
}
}