This topic is about Google Guice – @ProvidedBy Annotation.
@ProvidedBy annotation tells the guice about the provider of implementation class. No binding is required in Binding Module in such a case. See the example:
Example
Create a java class named GuiceTester.
GuiceTester.java
import com.google.inject.AbstractModule; import com.google.inject.Guice; import com.google.inject.Inject; import com.google.inject.Injector; import com.google.inject.ProvidedBy; import com.google.inject.Provider; public class GuiceTester { public static void main(String[] args) { Injector injector = Guice.createInjector(new TextEditorModule()); TextEditor editor = injector.getInstance(TextEditor.class); editor.makeSpellCheck(); } } class TextEditor { private SpellChecker spellChecker; @Inject public TextEditor( SpellChecker spellChecker) { this.spellChecker = spellChecker; } public void makeSpellCheck(){ spellChecker.checkSpelling(); } } //Binding Module class TextEditorModule extends AbstractModule { @Override protected void configure() { } } @ProvidedBy(SpellCheckerProvider.class) interface SpellChecker { public void checkSpelling(); } //spell checker implementation class SpellCheckerImpl implements SpellChecker { private String dbUrl; private String user; private Integer timeout; @Inject public SpellCheckerImpl(String dbUrl, String user, Integer timeout){ this.dbUrl = dbUrl; this.user = user; this.timeout = timeout; } @Override public void checkSpelling() { System.out.println("Inside checkSpelling." ); System.out.println(dbUrl); System.out.println(user); System.out.println(timeout); } } class SpellCheckerProvider implements Provider<SpellChecker>{ @Override public SpellChecker get() { String dbUrl = "jdbc:mysql://localhost:5326/emp"; String user = "user"; int timeout = 100; SpellChecker SpellChecker = new SpellCheckerImpl(dbUrl, user, timeout); return SpellChecker; } }
Output
Compile and run the file, you will see the following output.
Inside checkSpelling. jdbc:mysql://localhost:5326/emp user 100
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