ZPath and ZTemplate

A Java implementation of ZPath / ZTemplates from https://zpath.me

• Javadoc is always available at https://faceless2.github.io/zpath/docs/
• Jar is available at https://faceless2.github.io/zpath/dist/zpath-0.1.jar

ZPath API

import me.zpath.ZPath;
import java.util.List;

Object context = ...;
ZPath path = ZPath.compile("table/tr[td]");
List<Object> match = ZPath.evaluate(context).all();  // List of zero or more matches
Object match = ZPath.evaluate(context).first();      // The first match, or null if none

A ZPath can be compiled once and reused in multiple threads. context can be any type of object recognised by an EvalFactory registered with the implementation. The API ships with implementations for:

• org.w3c.dom.Node
• javax.json (any JSR353 implementation)
• com.bfo.json.Json (see http://faceless2.github.io/json)
• com.google.gson.JsonElement (see https://github.com/google/gson)
• java.util.Map and java.util.Collection - traversed without reflection (tested with Jackson and Gson)

ZTemplate API

import me.zpath.ZTemplate;
import java.io.Reader;

Object context = ...;
Reader reader = ...;
ZTemplate template = ZTemplate.compile(reader);
reader = template.apply(context);

// Or to write to an Appendable
Appendable out = new StringBuilder();
template.apply(context, out);

A ZTemplate can be compiled once and reused in multiple threads. context can be any type of object accepted by ZPath.

By default the "include" functionality is not enabled, for security, but it's easy to add if required, either using a default implementation to load from the file, or implement me.zpath.Includer

import me.zpath.ZTemplate;
import me.zpath.Includer;
import me.zpath.Configuration;
import java.io.*;

Includer includer = Includer.getDefault(new File("dir"));
Configuration conf = new Configuration().setTemplateIncluder(includer);
Reader reader = new InputStreamReader(new FileInputStream("dir/template.zt"), "UTF-8");
ZTemplate template = ZTemplate.compile(reader, conf);

ZPath with BFO Json

This is a complete example, using the "multiline string" syntax from Java 15 and based on the "BFO Json" library from https://github.com/faceless2/json

import com.bfo.json.Json;
import me.zpath.ZPath;

public class Test{
 public static void main(String...args) {
  Json json = Json.read("""
  {
   "person": {
    "name": {
     "first": "John",
     "last": "Smith"
    },
    "age": 27,
    "books": [
     {
      "name": "A Clockwork Orange",
      "author": "Anthony Burgess"
     },
     {
      "name": "Wolf Hall",
      "author": "Hilary Mantel"
     },
     {
      "name": "The First Man",
      "author": "Albert Camus"
     }
    ]
   }
  }
  """);

  ZPath.compile("person/name/first").eval(json).first(); // "John"

  ZPath.compile("count(person/books/*)").eval(json).first(); // 3

  ZPath.compile("**/author").eval(json).all();
    // ["Anthony Burgess", "Hilary Mantel", "Albert Camus"]
 }
}