jtulach@343: package org.apidesign.singletons.api;
jtulach@343: 
jtulach@343: import java.util.Iterator;
jtulach@343: import java.util.ServiceLoader;
jtulach@343: import org.openide.util.Lookup;
jtulach@343: 
jtulach@343: // BEGIN: singletons.injectable.api
jtulach@343: public abstract class DialogDisplayer {
jtulach@343:     protected DialogDisplayer() {
jtulach@343:     }
jtulach@343: 
jtulach@343:     /** Ask user a question.
jtulach@343:      *
jtulach@343:      * @param query the text of the question
jtulach@343:      * @return true if user confirmed or false if declined
jtulach@343:      */
jtulach@343:     public abstract boolean yesOrNo(String query);
jtulach@343: 
jtulach@343:     public static DialogDisplayer getDefault() {
jtulach@343:         return Impl.DEFAULT;
jtulach@343:     }
jtulach@343:     // FINISH: singletons.injectable.api
jtulach@343: 
jtulach@343: 
jtulach@343:     // BEGIN: singletons.injectable.dummyimpl
jtulach@343:     private static final class Impl extends DialogDisplayer {
jtulach@343:         private static final DialogDisplayer DEFAULT = initialize();
jtulach@343:         
jtulach@343:         @Override
jtulach@343:         public boolean yesOrNo(String query) {
jtulach@343:             System.err.printf("Saying no to '%s'\n", query);
jtulach@343:             return false;
jtulach@343:         }
jtulach@343:         // FINISH: singletons.injectable.dummyimpl
jtulach@343: 
jtulach@343:         private static DialogDisplayer initialize() {
jtulach@343:             if (Boolean.getBoolean("singleton.jdk6")) {
jtulach@343:                 return initializeServiceLoader();
jtulach@343:             } else {
jtulach@343:                 return initializeLookup();
jtulach@343:             }
jtulach@343:         }
jtulach@343:         
jtulach@343:         // BEGIN: singletons.injectable.serviceloader
jtulach@343:         private static DialogDisplayer initializeServiceLoader() {
jtulach@343:             Iterator<DialogDisplayer> it = null;
jtulach@343:             it = ServiceLoader.load(DialogDisplayer.class).iterator();
jtulach@343:             return it != null && it.hasNext() ? it.next() : new Impl();
jtulach@343:         }
jtulach@343:         // END: singletons.injectable.serviceloader
jtulach@343: 
jtulach@343:         // BEGIN: singletons.injectable.lookup
jtulach@343:         private static DialogDisplayer initializeLookup() {
jtulach@376:             final Lookup lkp = Lookup.getDefault();
jtulach@376:             DialogDisplayer def = lkp.lookup(DialogDisplayer.class);
jtulach@343:             return def != null ? def : new Impl();
jtulach@343:         }
jtulach@343:         // END: singletons.injectable.lookup
jtulach@343:     }
jtulach@343: }