ThreadLocalScript.java

package groovyx.cli;

import groovy.lang.Binding;
import groovy.lang.MissingPropertyException;
import groovy.lang.Script;

import java.util.HashMap;
import java.util.Map;

/**
 * Groovy Script base class that keeps bindings in a ThreadLocal so that scripts can
 * be run concurrently without much interference.  Note that the class properties of
 * the Script object *are* shared, which may or may not be what you want.  If you
 * don't want that then getProperty/setProperty/invokeMethod also need to be overridden.
 *
 * @author Jim White (<a href='https://github.com/jimwhite'>https://github.com/jimwhite</a>) on 8/8/14.
 */
abstract public class ThreadLocalScript extends Script {
    ThreadLocalScript() { super(new ThreadLocalBinding()); }

    public ThreadLocalScript(Binding binding) {
        super(new ThreadLocalBinding(binding));
    }

    @Override
    public void setBinding(Binding binding) {
        super.setBinding(new ThreadLocalBinding(binding));
    }

    static class ThreadLocalBinding extends Binding {
        ThreadLocal<Map> variables = new ThreadLocal<Map>();

        public ThreadLocalBinding() {
            variables.set(new HashMap());
        }

        public ThreadLocalBinding(Binding binding) {
            variables.set(binding.getVariables());
        }

        @Override
        public Object getVariable(String name) {
            Map map = variables.get();
            Object result = map.get(name);

            if (result == null && !map.containsKey(name)) {
                throw new MissingPropertyException(name, this.getClass());
            }

            return result;
        }

        @Override
        public boolean hasVariable(String name) {
            Map map = variables.get();
            return map != null && map.containsKey(name);
        }

        @Override
        public Map getVariables() {
            return variables.get();
        }
    }
}