package geektime.tdd.rest;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.ws.rs.HttpMethod;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.container.ResourceContext;
import jakarta.ws.rs.core.GenericEntity;
import jakarta.ws.rs.core.HttpHeaders;
import jakarta.ws.rs.core.Response;
import java.lang.reflect.Method;
import java.util.*;
import java.util.function.Function;
import java.util.stream.Collectors;
interface ResourceRouter {
OutboundResponse dispatch(HttpServletRequest request, ResourceContext resourceContext);
interface Resource {
Optional<ResourceMethod> match(UriTemplate.MatchResult result, String method, String[] mediaTypes, UriInfoBuilder builder);
}
interface RootResource extends Resource, UriHandler {
}
interface ResourceMethod extends UriHandler {
String getHttpMethod();
GenericEntity<?> call(ResourceContext resourceContext, UriInfoBuilder builder);
}
interface SubResourceLocator extends UriHandler {
}
}
class DefaultResourceRouter implements ResourceRouter {
private Runtime runtime;
private List<RootResource> rootResources;
public DefaultResourceRouter(Runtime runtime, List<RootResource> rootResources) {
this.runtime = runtime;
this.rootResources = rootResources;
}
@Override
public OutboundResponse dispatch(HttpServletRequest request, ResourceContext resourceContext) {
String path = request.getServletPath();
UriInfoBuilder uri = runtime.createUriInfoBuilder(request);
Optional<ResourceMethod> method = UriHandlers.mapMatched(path, rootResources, (result, resource) -> findResourceMethod(request, uri, result, resource));
if (method.isEmpty()) return (OutboundResponse) Response.status(Response.Status.NOT_FOUND).build();
return (OutboundResponse) method.map(m -> m.call(resourceContext, uri)).map(entity -> Response.ok(entity).build())
.orElseGet(() -> Response.noContent().build());
}
private Optional<ResourceMethod> findResourceMethod(HttpServletRequest request, UriInfoBuilder uri, Optional<UriTemplate.MatchResult> matched, RootResource handler) {
return handler.match(matched.get(), request.getMethod(),
Collections.list(request.getHeaders(HttpHeaders.ACCEPT)).toArray(String[]::new), uri);
}
}
class RootResourceClass implements ResourceRouter.RootResource {
private PathTemplate uriTemplate;
private Class<?> resourceClass;
private ResourceMethods resourceMethods;
public RootResourceClass(Class<?> resourceClass) {
this.resourceClass = resourceClass;
this.uriTemplate = new PathTemplate(resourceClass.getAnnotation(Path.class).value());
this.resourceMethods = new ResourceMethods(resourceClass.getMethods());
}
@Override
public Optional<ResourceRouter.ResourceMethod> match(UriTemplate.MatchResult result, String method, String[] mediaTypes, UriInfoBuilder builder) {
String remaining = Optional.ofNullable(result.getRemaining()).orElse("");
return resourceMethods.findResourceMethods(remaining, method);
}
@Override
public UriTemplate getUriTemplate() {
return uriTemplate;
}
}
class SubResource implements ResourceRouter.Resource {
private Object subResource;
private ResourceMethods resourceMethods;
public SubResource(Object subResource) {
this.subResource = subResource;
this.resourceMethods = new ResourceMethods(subResource.getClass().getMethods());
}
@Override
public Optional<ResourceRouter.ResourceMethod> match(UriTemplate.MatchResult result, String method, String[] mediaTypes, UriInfoBuilder builder) {
String remaining = Optional.ofNullable(result.getRemaining()).orElse("");
return resourceMethods.findResourceMethods(remaining, method);
}
}
class DefaultResourceMethod implements ResourceRouter.ResourceMethod {
private String httpMethod;
private UriTemplate uriTemplate;
private Method method;
public DefaultResourceMethod(Method method) {
this.method = method;
this.uriTemplate = new PathTemplate(Optional.ofNullable(method.getAnnotation(Path.class)).map(Path::value).orElse(""));
this.httpMethod = Arrays.stream(method.getAnnotations()).filter(a -> a.annotationType().isAnnotationPresent(HttpMethod.class))
.findFirst().get().annotationType().getAnnotation(HttpMethod.class).value();
}
@Override
public String getHttpMethod() {
return httpMethod;
}
@Override
public UriTemplate getUriTemplate() {
return uriTemplate;
}
@Override
public GenericEntity<?> call(ResourceContext resourceContext, UriInfoBuilder builder) {
return null;
}
@Override
public String toString() {
return method.getDeclaringClass().getSimpleName() + "." + method.getName();
}
}
class ResourceMethods {
private Map<String, List<ResourceRouter.ResourceMethod>> resourceMethods;
public ResourceMethods(Method[] methods) {
this.resourceMethods = getResourceMethods(methods);
}
private static Map<String, List<ResourceRouter.ResourceMethod>> getResourceMethods(Method[] methods) {
return Arrays.stream(methods).filter(m -> Arrays.stream(m.getAnnotations())
.anyMatch(a -> a.annotationType().isAnnotationPresent(HttpMethod.class)))
.map(DefaultResourceMethod::new)
.collect(Collectors.groupingBy(ResourceRouter.ResourceMethod::getHttpMethod));
}
public Optional<ResourceRouter.ResourceMethod> findResourceMethods(String path, String method) {
return Optional.ofNullable(resourceMethods.get(method)).flatMap(methods -> UriHandlers.match(path, methods, r -> r.getRemaining() == null));
}
}
class SubResourceLocators {
private final List<ResourceRouter.SubResourceLocator> subResourceLocators;
public SubResourceLocators(Method[] methods) {
subResourceLocators = Arrays.stream(methods).filter(m -> m.isAnnotationPresent(Path.class) &&
Arrays.stream(m.getAnnotations()).noneMatch(a -> a.annotationType().isAnnotationPresent(HttpMethod.class)))
.map((Function<Method, ResourceRouter.SubResourceLocator>) DefaultSubResourceLocator::new).toList();
}
public Optional<ResourceRouter.SubResourceLocator> findSubResource(String path) {
return UriHandlers.match(path, subResourceLocators);
}
static class DefaultSubResourceLocator implements ResourceRouter.SubResourceLocator {
private PathTemplate uriTemplate;
private Method method;
public DefaultSubResourceLocator(Method method) {
this.method = method;
this.uriTemplate = new PathTemplate(method.getAnnotation(Path.class).value());
}
@Override
public UriTemplate getUriTemplate() {
return uriTemplate;
}
@Override
public String toString() {
return method.getDeclaringClass().getSimpleName() + "." + method.getName();
}
}
}
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