ratpack.render.Renderer Maven / Gradle / Ivy
/*
* Copyright 2013 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package ratpack.render;
import com.google.common.reflect.TypeParameter;
import com.google.common.reflect.TypeToken;
import ratpack.api.NonBlocking;
import ratpack.handling.Context;
import ratpack.util.Types;
import java.util.function.BiConsumer;
/**
* A renderer is responsible for rendering an object to the response.
*
* Renderers are typically not used directly.
* Instead, they are used via by {@link Context#render(Object)} method.
*
* See {@link RendererSupport} for support base class for implementations.
*
* An alternative to implementing a renderer for a type is to make the type directly implement {@link Renderable}.
*
* @param The type of object that this renderer knows how to render.
* @see RendererSupport
* @see RenderableDecorator
* @see Renderable
*/
public interface Renderer {
/**
* Creates a renderer implementation from the given arguments.
*
* @param type the type of object-to-render
* @param impl the implementation of the {@link #render(Context, Object)} method
* @param the type of object-to-render
* @return a renderer implementation
*/
static Renderer of(Class type, BiConsumer impl) {
return new Renderer() {
@Override
public Class getType() {
return type;
}
@Override
public void render(Context context, T object) throws Exception {
impl.accept(context, object);
}
};
}
/**
* Creates a type token for a renderer of the given type of object.
*
* @param typeToRender the type that the renderer renders
* @param the type that the renderer renders
* @return a type token for a renderer of the given type of object
*/
static TypeToken> typeOf(Class typeToRender) {
return Types.intern(new TypeToken>(typeToRender) {}.where(new TypeParameter() {}, typeToRender));
}
/**
* The type of object that this renderer can render.
*
* @return The type of object that this renderer can render.
*/
Class getType();
/**
* Render the given object to the response.
*
* Calling this method will finalize the processing, sending the response to the client.
*
* Any errors that occur during rendering will be sent to {@link Context#error(Throwable)}.
*
* @param context the context for the operation
* @param object the object to render
* @throws Exception if anything goes wrong while rendering
*/
@NonBlocking
void render(Context context, T object) throws Exception;
}