StringTemplateParser

StringTemplateParser is the parser for string templates, where macros are defined with markers. During the parsing, macros are replaced by their values.

Usage of StringTemplateParser is simple:

    StringTemplateParser stp = new StringTemplateParser();
    stp.parse("xxx${small}xxx", String::toUpperCase);

The parse() method takes two arguments: the first is the template to parse. The second argument is a function that converts founded macros with the replacement values. In this example we simply convert a string to upper case.

MapTemplateParser

While StringTemplateParser has generic usage, more convenient implementation is the MapTemplateParser. It replaces macros with the map value:

    String template = "Hello ${foo}. Today is ${dayName}.";
    ...

    // prepare data
    Map<String, String> map = new HashMap<String, String>();
    map.put("foo", "Jodd");
    map.put("dayName", "Sunday");
    ...

    // parse
    ContextTemplateParser ctp = MapTemplateParser.of(map);

    String result = ctp.parse(template);

    // result == "Hello Jodd. Today is Sunday."

The parsing is done in two steps: the first is creation of ContextTemplateParser and the second is the actual call to parse() method. This is done in two steps as often we can re-use created ContextTemplateParser and repeat parsing on multiple input templates.

BeanTemplateParser

BeanTemplateParser is similar implementation to MapTemplateParser that works on any object. Template macros represents bean paths to the properties to fetch:

    BeanTemplateParser.of(bean).parse("Third user name: ${users[2].name}");

Configuration

StringTemplateParser (and it's variations) is very configurable. You can set the escape character, or starting and ending strings (by default: ${ and }). There is an option if missing keys should be resolved, and the replacement value for missing keys.

StringTemplateParser by default detects inner macros in passed string. However, you can turn on parsing values as well.