Scripting in Java Tutorial - Scripting in Java Binding

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A Bindings is a set of key-value pairs and the keys must be nonempty, non-null Strings.

Java Bindings is an instance of the Bindings interface.

SimpleBindings class is an implementation of the Bindings interface.

Bindings interface inherits from the Map<String,Object> interface.

Bindings is a Map with a restriction that its keys must be nonempty, non-null strings.

Example

import javax.script.Bindings;
import javax.script.SimpleBindings;
//from   w  ww  . j av  a 2  s .  com
public class Main {
  public static void main(String[] args) {
    Bindings params = new SimpleBindings();
    params.put("stringKey", "Hello");
    params.put("valueKey", 2015);

    Object msg = params.get("stringKey");
    Object year = params.get("valueKey");
    System.out.println("stringKey" + msg);
    System.out.println("valueKey = " + year);

    params.remove("valueKey");
    year = params.get("valueKey");

    boolean containsYear = params.containsKey("valueKey");
    System.out.println("valueKey = " + year);
    System.out.println("params contains year = " + containsYear);
  }
}

The code above generates the following result.

Example 2

To pass parameters from Java code to a script engine, use a createBindings() method from ScriptEngine interface which returns an instance of the Bindings interface.

import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
/*  w w w . j av  a  2s .co m*/
public class Main {
  public static void main(String[] args) {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("JavaScript");

        Bindings params = engine.createBindings();

    params.put("stringKey", "Hello");
    params.put("valueKey", 2015);

    Object msg = params.get("stringKey");
    Object year = params.get("valueKey");
    System.out.println("stringKey" + msg);
    System.out.println("valueKey = " + year);

    params.remove("valueKey");
    year = params.get("valueKey");

    boolean containsYear = params.containsKey("valueKey");
    System.out.println("valueKey = " + year);
    System.out.println("params contains year = " + containsYear);
  }
}

The code above generates the following result.

Reserved Keys for Engine Scope Bindings

Typically, a key in the engine scope Bindings represents a script variable.

The following table lists reserved keys with special meanings.

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