package io.dropwizard.jersey.guava;

import com.google.common.base.Optional;
import org.glassfish.jersey.internal.inject.InjectionManager;
import org.glassfish.jersey.internal.inject.Providers;
import org.glassfish.jersey.internal.util.ReflectionHelper;
import org.glassfish.jersey.internal.util.collection.ClassTypePair;

import javax.annotation.Nullable;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.ext.ParamConverter;
import javax.ws.rs.ext.ParamConverterProvider;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.List;

@Singleton
public class OptionalParamConverterProvider implements ParamConverterProvider {
    private final InjectionManager manager;

    @Inject
    public OptionalParamConverterProvider(final InjectionManager manager) {
        this.manager = manager;
    }

    
{@inheritDoc}
/** * {@inheritDoc} */
@Override @Nullable public <T> ParamConverter<T> getConverter(final Class<T> rawType, final Type genericType, final Annotation[] annotations) { if (Optional.class.equals(rawType)) { final List<ClassTypePair> ctps = ReflectionHelper.getTypeArgumentAndClass(genericType); final ClassTypePair ctp = (ctps.size() == 1) ? ctps.get(0) : null; if (ctp == null || ctp.rawClass() == String.class) { return new ParamConverter<T>() { @Override public T fromString(final String value) { return rawType.cast(Optional.fromNullable(value)); } @Override public String toString(final T value) { return value.toString(); } }; } for (ParamConverterProvider provider : Providers.getProviders(manager, ParamConverterProvider.class)) { final ParamConverter<?> converter = provider.getConverter(ctp.rawClass(), ctp.type(), annotations); if (converter != null) { return new ParamConverter<T>() { @Override public T fromString(final String value) { final Object convertedValue = value == null ? null : converter.fromString(value); return rawType.cast(Optional.fromNullable(convertedValue)); } @Override public String toString(final T value) { return value.toString(); } }; } } } return null; } }