juneau-examples/juneau-examples-rest/src/main/java/org/apache/juneau/examples/rest/PhotosResource.java

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package org.apache.juneau.examples.rest;

import static javax.servlet.http.HttpServletResponse.*;
import static org.apache.juneau.html.HtmlSerializer.*;
import static org.apache.juneau.http.HttpMethodName.*;

import java.awt.image.*;
import java.io.*;
import java.net.*;
import java.util.*;

import javax.imageio.*;

import org.apache.juneau.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.rest.*;
import org.apache.juneau.rest.annotation.*;
import org.apache.juneau.serializer.*;

/**
 * Sample resource that allows images to be uploaded and retrieved.
 */
@RestResource(
	path="/photos",
	messages="nls/PhotosResource",
	title="Photo REST service",
	description="Sample resource that allows images to be uploaded and retrieved.",
	htmldoc=@HtmlDoc(
		navlinks={
			"up: request:/..",
			"options: servlet:/?method=OPTIONS",
			"source: $C{Source/gitHub}/org/apache/juneau/examples/rest/$R{servletClassSimple}.java"
		},
		aside={
			"<div style='max-width:400px;min-width:200px' class='text'>",
			"	<p>Shows an example of using custom serializers and parsers to create REST interfaces over binary resources.</p>",
			"	<p>In this case, our resources are marshalled jpeg and png binary streams and are stored in an in-memory 'database' (also known as a <code>TreeMap</code>).</p>",
			"</div>"
		}
	),
	properties={
		// Make the anchor text on URLs be just the path relative to the servlet.
		@Property(name=HTML_uriAnchorText, value="SERVLET_RELATIVE")
	}
)
public class PhotosResource extends BasicRestServlet {
	private static final long serialVersionUID = 1L;

	// Our cache of photos
	private Map<String,Photo> photos = new TreeMap<>();

	@Override /* Servlet */
	public void init() {
		try (InputStream is = getClass().getResourceAsStream("averycutecat.jpg")) {
			BufferedImage image = ImageIO.read(is);
			Photo photo = new Photo("cat", image);
			photos.put(photo.id, photo);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	/** Our bean class for storing photos */
	public static class Photo {
		String id;
		BufferedImage image;

		Photo(String id, BufferedImage image) {
			this.id = id;
			this.image = image;
		}

		public URI getURI() throws URISyntaxException {
			return new URI("servlet:/" + id);
		}
	}

	/** GET request handler for list of all photos */
	@RestMethod(name=GET, path="/", summary="Show the list of all currently loaded photos")
	public Collection<Photo> getAllPhotos() throws Exception {
		return photos.values();
	}

	/** GET request handler for single photo */
	@RestMethod(name=GET, path="/{id}", serializers=ImageSerializer.class, summary="Get a photo by ID")
	public BufferedImage getPhoto(@Path String id) throws Exception {
		Photo p = photos.get(id);
		if (p == null)
			throw new RestException(SC_NOT_FOUND, "Photo not found");
		return p.image;
	}

	/** PUT request handler */
	@RestMethod(name=PUT, path="/{id}", parsers=ImageParser.class, summary="Add or overwrite a photo")
	public String addPhoto(@Path String id, @Body BufferedImage image) throws Exception {
		photos.put(id, new Photo(id, image));
		return "OK";
	}

	/** POST request handler */
	@RestMethod(name=POST, path="/", parsers=ImageParser.class, summary="Add a photo")
	public Photo setPhoto(@Body BufferedImage image) throws Exception {
		Photo p = new Photo(UUID.randomUUID().toString(), image);
		photos.put(p.id, p);
		return p;
	}

	/** DELETE request handler */
	@RestMethod(name=DELETE, path="/{id}", summary="Delete a photo by ID")
	public String deletePhoto(@Path String id) throws Exception {
		Photo p = photos.remove(id);
		if (p == null)
			throw new RestException(SC_NOT_FOUND, "Photo not found");
		return "OK";
	}

	/** Serializer for converting images to byte streams */
	public static class ImageSerializer extends OutputStreamSerializer {

		/**
		 * Constructor.
		 * @param ps The property store containing all the settings for this object.
		 */
		public ImageSerializer(PropertyStore ps) {
			super(ps, null, "image/png", "image/jpeg");
		}

		@Override /* Serializer */ 
		public OutputStreamSerializerSession createSession(SerializerSessionArgs args) {
			return new OutputStreamSerializerSession(args) {
				
				@Override /* SerializerSession */ 
				protected void doSerialize(SerializerPipe out, Object o) throws Exception {
					RenderedImage image = (RenderedImage)o;
					String mediaType = getProperty("mediaType", String.class, (String)null);
					ImageIO.write(image, mediaType.substring(mediaType.indexOf('/')+1), out.getOutputStream());
				}
			};
		}
	}

	/** Parser for converting byte streams to images */
	public static class ImageParser extends InputStreamParser {

		/**
		 * Constructor.
		 * @param ps The property store containing all the settings for this object.
		 */
		public ImageParser(PropertyStore ps) {
			super(ps, "image/png", "image/jpeg");
		}

		@Override /* Parser */
		public InputStreamParserSession createSession(final ParserSessionArgs args) {
			return new InputStreamParserSession(args) {
				
				@Override /* ParserSession */
				@SuppressWarnings("unchecked")
				protected <T> T doParse(ParserPipe pipe, ClassMeta<T> type) throws Exception {
					return (T)ImageIO.read(pipe.getInputStream());
				}
			};
		}
	}
}