The Java Developers Almanac 1.4


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Home > List of Packages > java.beans  [12 examples]

e6. Getting and Setting a Property of a Bean

This example demonstrates how to get and set the value of a property in a bean using Expression and Statement. The example gets and sets three types of properties, an Object, a primitive type, and an array. Both these classes use the name of the method that gets or sets the property.
    Object o = new MyBean();
    try {
        // Get the value of prop1
        Expression expr = new Expression(o, "getProp1", new Object[0]);
        expr.execute();
        String s = (String)expr.getValue();
    
        // Set the value of prop1
        Statement stmt = new Statement(o, "setProp1", new Object[]{"new string"});
        stmt.execute();
    
        // Get the value of prop2
        expr = new Expression(o, "getProp2", new Object[0]);
        expr.execute();
        int i = ((Integer)expr.getValue()).intValue();
    
        // Set the value of prop2
        stmt = new Statement(o, "setProp2", new Object[]{new Integer(123)});
        stmt.execute();
    
        // Get the value of prop1
        expr = new Expression(o, "getProp3", new Object[0]);
        expr.execute();
        byte[] bytes = (byte[])expr.getValue();
    
        // Set the value of prop1
        stmt = new Statement(o, "setProp3", new Object[]{new byte[]{0x12, 0x23}});
        stmt.execute();
    } catch (Exception e) {
    }
    
    public class MyBean {
        // Property prop1
        String prop1;
        public String getProp1() {
            return prop1;
        }
        public void setProp1(String s) {
            prop1 = s;
        }
    
        // Property prop2
        int prop2;
        public int getProp2() {
            return prop2;
        }
        public void setProp2(int i) {
            prop2 = i;
        }
    
        // Property prop3
        byte[] prop3;
        public byte[] getProp3() {
            return prop3;
        }
        public void setProp3(byte[] bytes) {
            prop3 = bytes;
        }
    }

 Related Examples
e1. The Quintessential Bean
e2. Implementing a Bound Property
e3. Implementing a Constrained Property
e4. Instantiating a Bean
e5. Listing the Property Names of a Bean

See also: Events    Serialization   


© 2002 Addison-Wesley.