org.beetl.core.Function Maven / Gradle / Ivy
/*
[The "BSD license"]
Copyright (c) 2011-2022 闲大赋 (李家智)
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
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notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.beetl.core;
import org.beetl.core.engine.GrammarCreator;
import org.beetl.core.statement.Expression;
/**
* Beetl 的函数接口，用户可以通过实现此接口来自定一方法
*
*
*
* 例如实现一个将字符创转为大写的函数 str.upcase
* str.upcase 接收一个字符串参数，并将其转为大写，如下调用
*
* hello,this is ${str.upcase(user.name)}
*
* group.registerFunction("str.upcase", new Function() {
* public String call(Object[] paras, Context ctx) {
* String str = (String) paras[0];
* return str.toUpperCase();
* }
* });
*
*
*
* @author xiandafu
* @since 1.1
*/
public interface Function {
/**
* @param paras beetl传递的参数
*/
Object call(Object[] paras, Context ctx);
/**
* 如果Function实现了此接口，则会添加额当前外行参
* @see org.beetl.ext.fn.DebugFunction
*/
static interface LineAware{}
/**
* 如果Function还实现了此接口，则此函数参数将使用安全输出符号
* @see org.beetl.ext.fn.IsNotEmptyExpressionFunction
*/
static interface ForceSafe{}
/**
* 如果Function实现了此接口，则入参会在解析的时候修改
* @see org.beetl.ext.fn.CheckExistFunction
*
*/
static interface ChangeInput{
public Expression[] update(GrammarCreator creator,Expression[] exps,GroupTemplate gt);
}
}