Basic AbstractInjectableProvider for building RESTful web services with Jersey using reflection to find the Super Type Tokens. See http://codyaray.com/2013/01/finding-generic-type-parameters-with-guava for details.

AbstractInjectableProvider.java

package com.mydomain.myapp.resources;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import javax.ws.rs.core.Context;

import com.sun.jersey.core.spi.component.ComponentContext;
import com.sun.jersey.core.spi.component.ComponentScope;
import com.sun.jersey.server.impl.inject.AbstractHttpContextInjectable;
import com.sun.jersey.spi.inject.Injectable;
import com.sun.jersey.spi.inject.InjectableProvider;

/**
 * Abstract class for making Jersey injectable providers.
 *
 * @param <T> the type of the injectable value.
 * @author codyaray
 * @since 2/01/2012
 * @see http://codahale.com/what-makes-jersey-interesting-injection-providers/
 */
public abstract class AbstractInjectableProvider<T> extends AbstractHttpContextInjectable<T>
    implements InjectableProvider<Context, Type> {

  // The type of T
  private final Type type;

  public AbstractInjectableProvider() {
    /*
     * Use reflection to get the "Super Type Token"
     * See http://gafter.blogspot.com/2006/12/super-type-tokens.html
     */

    // Because this class is abstract, getClass() must return a sub-class of it.
    // Traverse the hierarchy from the instantiated subclass to a direct subclass of this one
    Class<?> klass = getClass();
    while (!klass.getSuperclass().equals(AbstractInjectableProvider.class)) {
      klass = klass.getSuperclass();
    }

     // This operation is safe. Because klass is a direct sub-class, getGenericSuperclass() will
     // always return the Type of this class. Because this class is parameterized, the cast is safe
    ParameterizedType superclass = (ParameterizedType) klass.getGenericSuperclass();
    this.type = superclass.getActualTypeArguments()[0];
  }

  @Override
  public Injectable<T> getInjectable(ComponentContext componentContext, Context context, Type type) {
    return type.equals(this.type) ? getInjectable(componentContext, context) : null;
  }

  protected Injectable<T> getInjectable(ComponentContext componentContext, Context context) {
    return this;
  }

  @Override
  public ComponentScope getScope() {
    return ComponentScope.PerRequest;
  }
}