CODEWITHSUNDEEP
java
Chris
Chris

Reputation: 1363

Access and set a static variable with the name of the variable

What I want to do is access a variable stored in one class with a string. For example I have

public class Values {
    public static boolean enabled;
}

And then in a different part of the project I have the object and a string with the fields name. How do I get and set the value of the field?

Upvotes: 3

Views: 698

Answers (3)

chessofnerd
chessofnerd

Reputation: 1279

@Maricio Linhares's answer is very good; however, note that reflection is pretty slow. If you are doing this a lot you might have performance problems. An alternative might be to use a map. The code would follow as

public class Values {
    public static Map<string,bool> variableMap;

    public static void main(String[] args) throws Exception {           
        // adding a 'variable'
        variableMap = new YourFavoriteMapImplementation();
        variableMap.put("enabled",true);

        // accessing the 'variables' value
        bool val = variableMap.get("enabled");
        System.out.println(val);         
    }
}

Upvotes: 1

Maur&#237;cio Linhares
Maur&#237;cio Linhares

Reputation: 40333

If you have the name as a string, you should use reflection:

import java.lang.reflect.Field;


public class Values {

    public static boolean enabled = false;

    public static void main(String[] args) throws Exception {           
        Values v = new Values();

        Field field = v.getClass().getField("enabled");

        field.set( v, true );

        System.out.println( field.get(v) );         
    }

}

Upvotes: 9

Simeon Visser
Simeon Visser

Reputation: 122376

Values.enabled = true;

or

Values.enabled = false;

Alternatively, you can create a static getter and setter for the Values class and call those static methods instead.

Upvotes: 1

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