package com.coderising.litestruts.parser.xml;
/**
* Created by huitailang on 17/3/5.
* 普通记号解析器,处理#{}和${}参数
*/
public class GenericTokenParser {
//有一个开始和结束记号
private final String openToken;
private final String closeToken;
//记号处理器
private final TokenHandler handler;
public GenericTokenParser(String openToken, String closeToken, TokenHandler handler) {
this.openToken = openToken;
this.closeToken = closeToken;
this.handler = handler;
}
public String parse(String text) {
StringBuilder builder = new StringBuilder();
if (text != null && text.length() > 0) {
char[] src = text.toCharArray();
int offset = 0;
int start = text.indexOf(openToken, offset);
//#{favouriteSection,jdbcType=VARCHAR}
//这里是循环解析参数,参考GenericTokenParserTest,比如可以解析${first_name} ${initial} ${last_name} reporting.这样的字符串,里面有3个 ${}
while (start > -1) {
//判断一下 ${ 前面是否是反斜杠,这个逻辑在老版的mybatis中(如3.1.0)是没有的
if (start > 0 && src[start - 1] == '\\') {
// the variable is escaped. remove the backslash.
//新版已经没有调用substring了,改为调用如下的offset方式,提高了效率
//issue #760
builder.append(src, offset, start - offset - 1).append(openToken);
offset = start + openToken.length();
} else {
int end = text.indexOf(closeToken, start);
if (end == -1) {
builder.append(src, offset, src.length - offset);
offset = src.length;
} else {
builder.append(src, offset, start - offset);
offset = start + openToken.length();
String content = new String(src, offset, end - offset);
//得到一对大括号里的字符串后,调用handler.handleToken,比如替换变量这种功能
builder.append(handler.handleToken(content));
offset = end + closeToken.length();
}
}
start = text.indexOf(openToken, offset);
}
if (offset < src.length) {
builder.append(src, offset, src.length - offset);
}
}
return builder.toString();
}
}