This project is about configuration of applications, most notably via CDI injection, and about parameterization of Objects.

Changes january 2025: improved reflexive code, restricted CDI property annotation to fields and methods

Changes december 2024: removed xml based setup, removed Date support in favor of LocalDateTime and improved docs and logging

code examples

        <dependencies>
            <dependency>
                <!--only when working with CDI-->
                <groupId>jakarta.platform</groupId>
                <artifactId>jakarta.jakartaee-api</artifactId>
                <version>10.0.0</version>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>com.vectorprint</groupId>
                <artifactId>Config</artifactId>
                <version>13.0</version>
            </dependency>
        </dependencies>

CDI, the preferred way

import jakarta.enterprise.context.ApplicationScoped;

/** Configure property (re)loading */
@ApplicationScoped
public class PropertyLocationProvider {

    @Produces @ConfigFileUrls
    public String[] getUrl() {return new String[]{"/etc/stdw.properties"};}

    /** when true the url must be in the form "classpath:/pathto/my.properties" */
    @Produces @FromJar
    public boolean fromJar() {return false;}

    @Produces @AutoReload
    public boolean autoRload() {return true;}

    @Produces @POLL_INTERVAL
    public int pollInterval() {return 10;}
}

/** a bean with properties */
@ApplicationScoped
public class MyBean {
    
    /** A non required property that will not be reloaded despite update is true */
    @Inject @Property(defaultValue = "30",required = false,updatable = true)
    private int timeoutSeconds;

    private int[] test;
    /** A required property that changes when the corresponding value in the properties file changes */
    @Inject
    @Property(required=true, keys="testkey")
    public void setTest(int[] test) {
        test=test;
    }
    
}

NOTE for method injection the corresponding name(s) in the properties file is(are) either the method name or the keys parameter in @Property

NOTE Reloading works for Singleton beans, static properties, method and for @inject @Properties EnhancedMap

Plain Java example with an Observer

   static class MyObserver implements PropertyChangeListener {
        @Override
        public void propertyChange(PropertyChangeEvent propertyChangeEvent) {}
    }
    
    public class Example {

        private ObservableProperties mtp =
                new ObservableProperties(new ParsingProperties(new Settings(), "/etc/app.properties"));
        private MyObserver os = new MyObserver();
        private boolean prop;
        
        public Example() {
            mtp.addObserver(os);
            prop=mtp.getBooleanProperty(null,"prop");
        }
    }

Java annotations example

public class Fields {
    @Setting
    private boolean b;
    @SettingsField(observable = true, readonly = true, cache = true,....)
    private EnhancedMap settings;
}

public class Fields2 {
    @Setting
    private static boolean b;
}

public class Example {
    private final SettingsAnnotationProcessor sap = new SettingsAnnotationProcessorImpl();
    private final EnhancedMap eh = new ParsingProperties(new Settings(), "/etc/app.properties");
    private Fields f = new Fields();

    public Example() {
        sap.initSettings(f,eh);
        sap.initSettings(Fields2.class,eh);
    }

}

The library offers syntax support for settings and parameters in a loosely coupled manner. An enhanced java properties syntax and json are built-in. You are not restricted to the built-in syntaxes, you can provide your own, using javacc and spi, see SettinsBindingService.getFactory() and the junit tests.

At runtime this library tracks keys for which a default is used when no value is found. It tracks unused keys as well.

You can declare multiple features for settings such as caching, preparing keys and values, auto reloading, readonlyness, threadsafety, help for properties, reading / parsing from input. You can also develop your own features for settings.