VideoServiceWithDataRest

VideoSvcApi.java

package org.magnum.mobilecloud.video.client;

import java.util.Collection;

import org.magnum.mobilecloud.video.repository.Video;

import retrofit.http.Body;
import retrofit.http.GET;
import retrofit.http.POST;
import retrofit.http.Query;

/**
 * This interface defines an API for a VideoSvc. The
 * interface is used to provide a contract for client/server
 * interactions. The interface is annotated with Retrofit
 * annotations so that clients can automatically convert the
 * 
 * 
 * @author jules
 *
 */
public interface VideoSvcApi {
	
	public static final String TITLE_PARAMETER = "title";
	
	public static final String DURATION_PARAMETER = "duration";

	// The path where we expect the VideoSvc to live
	public static final String VIDEO_SVC_PATH = "/video";

	// The path to search videos by title
	public static final String VIDEO_TITLE_SEARCH_PATH = VIDEO_SVC_PATH + "/search/findByName";
	
	// The path to search videos by title
	public static final String VIDEO_DURATION_SEARCH_PATH = VIDEO_SVC_PATH + "/search/findByDurationLessThan";

	@GET(VIDEO_SVC_PATH)
	public Collection<Video> getVideoList();
	
	@POST(VIDEO_SVC_PATH)
	public Void addVideo(@Body Video v);
	
	@GET(VIDEO_TITLE_SEARCH_PATH)
	public Collection<Video> findByTitle(@Query(TITLE_PARAMETER) String title);
	
	@GET(VIDEO_DURATION_SEARCH_PATH)
	public Collection<Video> findByDurationLessThan(@Query(DURATION_PARAMETER) String title);
	
}

package org.magnum.mobilecloud.video.client;

import java.util.Collection;

import org.magnum.mobilecloud.video.repository.Video;

import retrofit.http.Body;

import retrofit.http.GET;

import retrofit.http.POST;

import retrofit.http.Query;

/**

* This interface defines an API for a VideoSvc. The

* interface is used to provide a contract for client/server

* interactions. The interface is annotated with Retrofit

* annotations so that clients can automatically convert the

* @author jules

public interface VideoSvcApi {

public static final String TITLE_PARAMETER = "title";

public static final String DURATION_PARAMETER = "duration";

// The path where we expect the VideoSvc to live

public static final String VIDEO_SVC_PATH = "/video";

// The path to search videos by title

public static final String VIDEO_TITLE_SEARCH_PATH = VIDEO_SVC_PATH + "/search/findByName";

// The path to search videos by title

public static final String VIDEO_DURATION_SEARCH_PATH = VIDEO_SVC_PATH + "/search/findByDurationLessThan";

@GET(VIDEO_SVC_PATH)

public Collection<Video> getVideoList();

@POST(VIDEO_SVC_PATH)

public Void addVideo(@Body Video v);

@GET(VIDEO_TITLE_SEARCH_PATH)

public Collection<Video> findByTitle(@Query(TITLE_PARAMETER) String title);

@GET(VIDEO_DURATION_SEARCH_PATH)

public Collection<Video> findByDurationLessThan(@Query(DURATION_PARAMETER) String title);

}

ResourcesMapper.java

package org.magnum.mobilecloud.video.json;

import java.io.IOException;

import org.springframework.hateoas.Resources;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;

/**
 * <Begin long explanation of why this class was created...>
 * 
 * 
 * By default, Spring Data Rest uses a format called HATEOAS (http://en.wikipedia.org/wiki/HATEOAS)
 * to output the data returned from a Repository. The results from findAll(), findByName(), etc. are
 * wrapped in an Object called Resources. When this Resources object is converted to JSON, it adds
 * additional fields to the JSON so that we don't just get back a list of Video objects.
 * 
 * For our VideoRepository, the default output would like something like this for the /video :
 * 
 * {
    "_links": {
        "search": {
            "href": "http://localhost:8080/video/search"
        }
    },
    "_embedded": {
        "videos": [
            {
                "name": "Foo",
                "url": null,
                "duration": 100,
                "_links": {
                    "self": {
                        "href": "http://localhost:8080/video/1"
                    }
                }
            }
        ]
    }
}
 * You can comment out the Application.halObjectMapper() and rerun the application if you would
 * like to see what the default format looks like with full HATEOAS.
 * 
 * For this simple example, the extra HATEOAS "_embedded" and "_links" formatting for the top-level
 * JSON adds extra complexity. Because of the format, we can't just directly unmarshall this response
 * into a list of Video objects.
 * 
 * To simplify this example and make it possible to directly unmarshall the responses as a list of 
 * Video objects, this ObjectMapper overrides the default JSON marshalling of Spring Data Rest so
 * that it outputs this instead:
 * 
 * [
    {
        "name": "Foo",
        "url": null,
        "duration": 100,
        "_links": {
            "self": {
                "href": "http://localhost:8080/video/1"
            }
        }
    }
   ]
 * 
 * This alternate format allows us to directly unmarshall the HTTP response bodies from the VideoRepository
 * into a list of Video objects.
 * 
 * @author jules
 *
 */
public class ResourcesMapper extends ObjectMapper {

	// This anonymous inner class will handle conversion of the Spring Data Rest
	// Resources objects into JSON. Resources are objects that Spring Data Rest
	// creates with the Videos it obtains from your VideoRepository
	@SuppressWarnings("rawtypes")
	private JsonSerializer<Resources> serializer = new JsonSerializer<Resources>() {

		// We are going to register this class to handle all instances of type
		// Resources
		@Override
		public Class<Resources> handledType() {
			return Resources.class;
		}

		@Override
		public void serialize(Resources value, JsonGenerator jgen,
				SerializerProvider provider) throws IOException,
				JsonProcessingException {
			// Extracted the actual data inside of the Resources object
			// that we care about (e.g., the list of Video objects)
			Object content = value.getContent();
			// Instead of all of the Resources member variables, etc.
			// Just mashall the actual content (Videos) into the JSON
			JsonSerializer<Object> s = provider.findValueSerializer(
					content.getClass(), null);
			s.serialize(content, jgen, provider);
		}
	};
	
	// Create an ObjectMapper and tell it to use our customer serializer
	// to convert Resources objects into JSON
	public ResourcesMapper() {
		SimpleModule module = new SimpleModule();
		module.addSerializer(serializer);
		registerModule(module);
	}

}

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package org.magnum.mobilecloud.video.json;

import java.io.IOException;

import org.springframework.hateoas.Resources;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.JsonSerializer;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.SerializerProvider;

import com.fasterxml.jackson.databind.module.SimpleModule;

/**

* <Begin long explanation of why this class was created...>

* By default, Spring Data Rest uses a format called HATEOAS (http://en.wikipedia.org/wiki/HATEOAS)

* to output the data returned from a Repository. The results from findAll(), findByName(), etc. are

* wrapped in an Object called Resources. When this Resources object is converted to JSON, it adds

* additional fields to the JSON so that we don't just get back a list of Video objects.

* For our VideoRepository, the default output would like something like this for the /video :

* {

"_links": {

"search": {

"href": "http://localhost:8080/video/search"

}

"_embedded": {

"videos": [

{

"name": "Foo",

"url": null,

"duration": 100,

"_links": {

"self": {

"href": "http://localhost:8080/video/1"

}

]

}

* You can comment out the Application.halObjectMapper() and rerun the application if you would

* like to see what the default format looks like with full HATEOAS.

* For this simple example, the extra HATEOAS "_embedded" and "_links" formatting for the top-level

* JSON adds extra complexity. Because of the format, we can't just directly unmarshall this response

* into a list of Video objects.

* To simplify this example and make it possible to directly unmarshall the responses as a list of

* Video objects, this ObjectMapper overrides the default JSON marshalling of Spring Data Rest so

* that it outputs this instead:

* [

{

"name": "Foo",

"url": null,

"duration": 100,

"_links": {

"self": {

"href": "http://localhost:8080/video/1"

}

]

* This alternate format allows us to directly unmarshall the HTTP response bodies from the VideoRepository

* into a list of Video objects.

* @author jules

public class ResourcesMapper extends ObjectMapper {

// This anonymous inner class will handle conversion of the Spring Data Rest

// Resources objects into JSON. Resources are objects that Spring Data Rest

// creates with the Videos it obtains from your VideoRepository

@SuppressWarnings("rawtypes")

private JsonSerializer<Resources> serializer = new JsonSerializer<Resources>() {

// We are going to register this class to handle all instances of type

// Resources

@Override

public Class<Resources> handledType() {

return Resources.class;

}

@Override

public void serialize(Resources value, JsonGenerator jgen,

SerializerProvider provider) throws IOException,

JsonProcessingException {

// Extracted the actual data inside of the Resources object

// that we care about (e.g., the list of Video objects)

Object content = value.getContent();

// Instead of all of the Resources member variables, etc.

// Just mashall the actual content (Videos) into the JSON

JsonSerializer<Object> s = provider.findValueSerializer(

content.getClass(), null);

s.serialize(content, jgen, provider);

}

};

// Create an ObjectMapper and tell it to use our customer serializer

// to convert Resources objects into JSON

public ResourcesMapper() {

SimpleModule module = new SimpleModule();

module.addSerializer(serializer);

registerModule(module);

}

Video.java

package org.magnum.mobilecloud.video.repository;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import com.google.common.base.Objects;

/**
 * A simple object to represent a video and its URL for viewing.
 * 
 * @author jules
 * 
 */
@Entity
public class Video {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private long id;

	private String name;
	private String url;
	private long duration;

	public Video() {
	}

	public Video(String name, String url, long duration) {
		super();
		this.name = name;
		this.url = url;
		this.duration = duration;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public long getDuration() {
		return duration;
	}

	public void setDuration(long duration) {
		this.duration = duration;
	}

	public long getId() {
		return id;
	}

	public void setId(long id) {
		this.id = id;
	}

	/**
	 * Two Videos will generate the same hashcode if they have exactly the same
	 * values for their name, url, and duration.
	 * 
	 */
	@Override
	public int hashCode() {
		// Google Guava provides great utilities for hashing
		return Objects.hashCode(name, url, duration);
	}

	/**
	 * Two Videos are considered equal if they have exactly the same values for
	 * their name, url, and duration.
	 * 
	 */
	@Override
	public boolean equals(Object obj) {
		if (obj instanceof Video) {
			Video other = (Video) obj;
			// Google Guava provides great utilities for equals too!
			return Objects.equal(name, other.name)
					&& Objects.equal(url, other.url)
					&& duration == other.duration;
		} else {
			return false;
		}
	}

}

package org.magnum.mobilecloud.video.repository;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import com.google.common.base.Objects;

/**

* A simple object to represent a video and its URL for viewing.

* @author jules

@Entity

public class Video {

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

private long id;

private String name;

private String url;

private long duration;

public Video() {

}

public Video(String name, String url, long duration) {

super();

this.name = name;

this.url = url;

this.duration = duration;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

public long getDuration() {

return duration;

}

public void setDuration(long duration) {

this.duration = duration;

}

public long getId() {

return id;

}

public void setId(long id) {

this.id = id;

}

/**

* Two Videos will generate the same hashcode if they have exactly the same

* values for their name, url, and duration.

@Override

public int hashCode() {

// Google Guava provides great utilities for hashing

return Objects.hashCode(name, url, duration);

}

/**

* Two Videos are considered equal if they have exactly the same values for

* their name, url, and duration.

@Override

public boolean equals(Object obj) {

if (obj instanceof Video) {

Video other = (Video) obj;

// Google Guava provides great utilities for equals too!

return Objects.equal(name, other.name)

&& Objects.equal(url, other.url)

&& duration == other.duration;

} else {

return false;

}

VideoRepository.java

package org.magnum.mobilecloud.video.repository;

import java.util.Collection;

import org.magnum.mobilecloud.video.client.VideoSvcApi;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;

/**
 * An interface for a repository that can store Video
 * objects and allow them to be searched by title.
 * 
 * @author jules
 *
 */
// This @RepositoryRestResource annotation tells Spring Data Rest to
// expose the VideoRepository through a controller and map it to the 
// "/video" path. This automatically enables you to do the following:
//
// 1. List all videos by sending a GET request to /video 
// 2. Add a video by sending a POST request to /video with the JSON for a video
// 3. Get a specific video by sending a GET request to /video/{videoId}
//    (e.g., /video/1 would return the JSON for the video with id=1)
// 4. Send search requests to our findByXYZ methods to /video/search/findByXYZ
//    (e.g., /video/search/findByName?title=Foo)
//
@RepositoryRestResource(path = VideoSvcApi.VIDEO_SVC_PATH)
public interface VideoRepository extends CrudRepository<Video, Long>{

	// Find all videos with a matching title (e.g., Video.name)
	public Collection<Video> findByName(
			// The @Param annotation tells Spring Data Rest which HTTP request
			// parameter it should use to fill in the "title" variable used to
			// search for Videos
			@Param(VideoSvcApi.TITLE_PARAMETER) String title);
	
	// Find all videos that are shorter than a specified duration
	public Collection<Video> findByDurationLessThan(
			// The @Param annotation tells tells Spring Data Rest which HTTP request
			// parameter it should use to fill in the "duration" variable used to
			// search for Videos
			@Param(VideoSvcApi.DURATION_PARAMETER) long maxduration);
	
	/*
	 * See: http://docs.spring.io/spring-data/jpa/docs/1.3.0.RELEASE/reference/html/jpa.repositories.html 
	 * for more examples of writing query methods
	 */
	
}

package org.magnum.mobilecloud.video.repository;

import java.util.Collection;

import org.magnum.mobilecloud.video.client.VideoSvcApi;

import org.springframework.data.repository.CrudRepository;

import org.springframework.data.repository.query.Param;

import org.springframework.data.rest.core.annotation.RepositoryRestResource;

/**

* An interface for a repository that can store Video

* objects and allow them to be searched by title.

* @author jules

// This @RepositoryRestResource annotation tells Spring Data Rest to

// expose the VideoRepository through a controller and map it to the

// "/video" path. This automatically enables you to do the following:

// 1. List all videos by sending a GET request to /video

// 2. Add a video by sending a POST request to /video with the JSON for a video

// 3. Get a specific video by sending a GET request to /video/{videoId}

// (e.g., /video/1 would return the JSON for the video with id=1)

// 4. Send search requests to our findByXYZ methods to /video/search/findByXYZ

// (e.g., /video/search/findByName?title=Foo)

@RepositoryRestResource(path = VideoSvcApi.VIDEO_SVC_PATH)

public interface VideoRepository extends CrudRepository<Video, Long>{

// Find all videos with a matching title (e.g., Video.name)

public Collection<Video> findByName(

// The @Param annotation tells Spring Data Rest which HTTP request

// parameter it should use to fill in the "title" variable used to

// search for Videos

@Param(VideoSvcApi.TITLE_PARAMETER) String title);

// Find all videos that are shorter than a specified duration

public Collection<Video> findByDurationLessThan(

// The @Param annotation tells tells Spring Data Rest which HTTP request

// parameter it should use to fill in the "duration" variable used to

// search for Videos

@Param(VideoSvcApi.DURATION_PARAMETER) long maxduration);

* See: http://docs.spring.io/spring-data/jpa/docs/1.3.0.RELEASE/reference/html/jpa.repositories.html

* for more examples of writing query methods

}

Application.java

package org.magnum.mobilecloud.video;

import org.magnum.mobilecloud.video.json.ResourcesMapper;
import org.magnum.mobilecloud.video.repository.VideoRepository;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import com.fasterxml.jackson.databind.ObjectMapper;

//Tell Spring to automatically inject any dependencies that are marked in
//our classes with @Autowired
@EnableAutoConfiguration
// Tell Spring to automatically create a JPA implementation of our
// VideoRepository
@EnableJpaRepositories(basePackageClasses = VideoRepository.class)
// Tell Spring to turn on WebMVC (e.g., it should enable the DispatcherServlet
// so that requests can be routed to our Controllers)
@EnableWebMvc
// Tell Spring that this object represents a Configuration for the
// application
@Configuration
// Tell Spring to go and scan our controller package (and all sub packages) to
// find any Controllers or other components that are part of our applciation.
// Any class in this package that is annotated with @Controller is going to be
// automatically discovered and connected to the DispatcherServlet.
@ComponentScan
public class Application extends RepositoryRestMvcConfiguration {

	// Tell Spring to launch our app!
	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
	
	// We are overriding the bean that RepositoryRestMvcConfiguration 
	// is using to convert our objects into JSON so that we can control
	// the format. The Spring dependency injection will inject our instance
	// of ObjectMapper in all of the spring data rest classes that rely
	// on the ObjectMapper. This is an example of how Spring dependency
	// injection allows us to easily configure dependencies in code that
	// we don't have easy control over otherwise.
	//
	// Normally, we would not override this object mapping. However, in this
	// case, we are overriding the JSON conversion so that we can easily
	// extract a list of videos, etc. using Retrofit. You can remove this
	// method from the class to see what the default HATEOAS-based responses
	// from Spring Data Rest look like. You will need to access the server
	// from your browser as removing this method will break the Retrofit 
	// client.
	//
	// See the ResourcesMapper class for more details.
	@Override
	public ObjectMapper halObjectMapper(){
		return new ResourcesMapper();
	}

}

package org.magnum.mobilecloud.video;

import org.magnum.mobilecloud.video.json.ResourcesMapper;

import org.magnum.mobilecloud.video.repository.VideoRepository;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

import org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration;

import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import com.fasterxml.jackson.databind.ObjectMapper;

//Tell Spring to automatically inject any dependencies that are marked in

//our classes with @Autowired

@EnableAutoConfiguration

// Tell Spring to automatically create a JPA implementation of our

// VideoRepository

@EnableJpaRepositories(basePackageClasses = VideoRepository.class)

// Tell Spring to turn on WebMVC (e.g., it should enable the DispatcherServlet

// so that requests can be routed to our Controllers)

@EnableWebMvc

// Tell Spring that this object represents a Configuration for the

// application

@Configuration

// Tell Spring to go and scan our controller package (and all sub packages) to

// find any Controllers or other components that are part of our applciation.

// Any class in this package that is annotated with @Controller is going to be

// automatically discovered and connected to the DispatcherServlet.

@ComponentScan

public class Application extends RepositoryRestMvcConfiguration {

// Tell Spring to launch our app!

public static void main(String[] args) {

SpringApplication.run(Application.class, args);

}

// We are overriding the bean that RepositoryRestMvcConfiguration

// is using to convert our objects into JSON so that we can control

// the format. The Spring dependency injection will inject our instance

// of ObjectMapper in all of the spring data rest classes that rely

// on the ObjectMapper. This is an example of how Spring dependency

// injection allows us to easily configure dependencies in code that

// we don't have easy control over otherwise.

// Normally, we would not override this object mapping. However, in this

// case, we are overriding the JSON conversion so that we can easily

// extract a list of videos, etc. using Retrofit. You can remove this

// method from the class to see what the default HATEOAS-based responses

// from Spring Data Rest look like. You will need to access the server

// from your browser as removing this method will break the Retrofit

// client.

// See the ResourcesMapper class for more details.

@Override

public ObjectMapper halObjectMapper(){

return new ResourcesMapper();

}