open-JSD-9943/src/main/java/com/fr/plugin/third/party/jsdjjed/schedule/utils/PlaceholderResolver.java

package com.fr.plugin.third.party.jsdjjed.schedule.utils;

import com.fr.log.FineLoggerFactory;
import com.fr.script.Calculator;
import com.fr.stable.StringUtils;
import com.fr.stable.UtilEvalError;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @Author: xx
 * @Date: 2020/9/13 11:44
 */
public class PlaceholderResolver {

    public static final String TEXT = "这是一个包含日期：${today()}和当前时间：${now()} 的两个公式文本";

    /**
     * 默认前缀占位符
     */
    public static final String DEFAULT_PLACEHOLDER_PREFIX = "${";

    /**
     * 默认后缀占位符
     */
    public static final String DEFAULT_PLACEHOLDER_SUFFIX = "}";

    /**
     * 默认单例解析器
     */
    private static PlaceholderResolver defaultResolver = new PlaceholderResolver();

    /**
     * 占位符前缀
     */
    private String placeholderPrefix = DEFAULT_PLACEHOLDER_PREFIX;

    /**
     * 占位符后缀
     */
    private String placeholderSuffix = DEFAULT_PLACEHOLDER_SUFFIX;


    private PlaceholderResolver() {
    }

    private PlaceholderResolver(String placeholderPrefix, String placeholderSuffix) {
        this.placeholderPrefix = placeholderPrefix;
        this.placeholderSuffix = placeholderSuffix;
    }

    /**
     * 获取默认的占位符解析器，即占位符前缀为"${", 后缀为"}"
     *
     * @return
     */
    public static PlaceholderResolver getDefaultResolver() {
        return defaultResolver;
    }

    public static PlaceholderResolver getResolver(String placeholderPrefix, String placeholderSuffix) {
        return new PlaceholderResolver(placeholderPrefix, placeholderSuffix);
    }

    /**
     * 解析带有指定占位符的模板字符串，默认占位符为前缀：${  后缀：}
     * 如："这是一个包含日期：${today()}和当前时间：${sum(1,2)} 的两个公式文本"
     *
     * @param content 要解析的带有占位符的模板字符串
     * @return
     */
    public String resolve(String content) {
        int start = content.indexOf(this.placeholderPrefix);
        if (start == -1) {
            return content;
        }

        int valueIndex = 0;
        StringBuilder resultContent = new StringBuilder(content);
        while (start != -1) {
            int end = resultContent.indexOf(this.placeholderSuffix);
            String place = content.substring(start, end + this.placeholderSuffix.length());
            String formula = place.replace(this.placeholderPrefix, "").replace(this.placeholderSuffix, "");
            Calculator calculator = Calculator.createCalculator();
            String value = StringUtils.EMPTY;
            try {
                Object o = calculator.evalValue(formula);

             if (o!=null){
                 if (o instanceof Date){
                     SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                     value = format.format(o);
                 }else {
                     value =o.toString();
                 }
             }

            } catch (UtilEvalError utilEvalError) {
                FineLoggerFactory.getLogger().error(utilEvalError,"JSD:>>calculator formula in text error!",utilEvalError.getMessage());
            }
            resultContent.replace(start, end + this.placeholderSuffix.length(), value);
            start = resultContent.indexOf(this.placeholderPrefix, start + value.length());
        }
        return resultContent.toString();
    }




}