I have been trying to get Guice working but end up with this:
Classes must have either one (and only one) constructor
My interface:
public interface AddrBookStore {
public Contact getContactByKey(String key);
public void addContact(Contact c);
}
The implementation:
public class RdbmsBasedAddrBookStore implements AddrBookStore {
private Connection connection;
public RdbmsBasedAddrBookStore(Connection connection) {
this.connection = connection;
}
@Override
public Contact getContactByKey(String key) throws AddrBookException
{}
@Override
public void addContact(Contact c) throws AddrBookException
{}
}
The binding module:
public class ABguiceConfingModule extends AbstractModule {
@Override
protected void configure() {
bind(AddrBookStore.class).to(RdbmsBasedAddrBookStore.class);
}
}
The AddrBook
client where I am injecting:
public class AddrBook {
private AddrBookStore store;
@Inject
public AddrBook(AddrBookStore store)
{
this.store = store;
}
... other methods;
}
And my main:
public class App
{
public static void main( String[] args ) throws Exception
{
Injector injector = Guice.createInjector(new ABguiceConfingModule() );
AddrBookStore store = injector.getInstance( AddrBookStore.class );
AddrBook book = new AddrBook(store);
AddrBookCLI cli = new AddrBookCLI(book);
cli.interact(new InputStreamReader(System.in), new OutputStreamWriter(System.out));
}}
After all this, I'm getting this error:
1) Could not find a suitable constructor in addrbook.store.RdbmsBasedAddrBookStore. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
[ERROR] at addrbook.store.RdbmsBasedAddrBookStore.class(RdbmsBasedAddrBookStore.java:23)
[ERROR] at addrbook.ABguiceConfingModule.configure(ABguiceConfingModule.java:13)
I have experience with Spring and not with Guice. Where am I going wrong here?
AddrBookStore
. You need to have a binding for Connection
, and then you need to annotate the constructor with @Inject
.You've set up the AddrBookStore
class but clearly it's wrapping an Rdbms... except you haven't set up the Rdbms
.
There are lots of ways to do this in Guice, in this case I would probably do it with a Provider<Connection>
, that way you have an entire class to put the code for spinning up your connection to the database, so something like:
public class ConnectionProvider implements Provider<Connection> {
public Connection get() {
// put your code that connects to the database here
}
}
Then your module would be:
public class ABguiceConfingModule extends AbstractModule {
@Override
protected void configure() {
bind(AddrBookStore.class).to(RdbmsBasedAddrBookStore.class);
bind(Connection.class).toProvider(ConnectionProvider.class);
}
}
And then finally your AddrBookStore
:
public class RdbmsBasedAddrBookStore implements AddrBookStore {
private Connection connection;
@Inject
public RdbmsBasedAddrBookStore(Connection connection) {
this.connection = connection;
}
@Override
public Contact getContactByKey(String key) throws AddrBookException
{}
@Override
public void addContact(Contact c) throws AddrBookException
{}
}
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