org.jooby.hbs.Hbs.java Source code

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Here is the source code for org.jooby.hbs.Hbs.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.jooby.hbs;

import static java.util.Objects.requireNonNull;

import java.util.function.Consumer;

import org.jooby.Body;
import org.jooby.Env;
import org.jooby.Jooby;
import org.jooby.View;

import com.github.jknack.handlebars.Context;
import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Template;
import com.github.jknack.handlebars.cache.GuavaTemplateCache;
import com.github.jknack.handlebars.cache.NullTemplateCache;
import com.github.jknack.handlebars.context.FieldValueResolver;
import com.github.jknack.handlebars.context.JavaBeanValueResolver;
import com.github.jknack.handlebars.context.MapValueResolver;
import com.github.jknack.handlebars.context.MethodValueResolver;
import com.github.jknack.handlebars.io.ClassPathTemplateLoader;
import com.google.common.cache.CacheBuilder;
import com.google.inject.Binder;
import com.google.inject.Key;
import com.google.inject.multibindings.Multibinder;
import com.google.inject.name.Names;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;

public class Hbs implements Jooby.Module {

    private static class Engine implements View.Engine {

        private Handlebars handlebars;

        public Engine(final Handlebars handlebars) {
            this.handlebars = requireNonNull(handlebars, "A handlebars instance required.");
        }

        @Override
        public String name() {
            return "hbs";
        }

        @Override
        public void render(final View view, final Body.Writer writer) throws Exception {
            Template template = handlebars.compile(view.name());

            final Context context;
            Object model = view.model();
            if (model instanceof Context) {
                context = (Context) model;
            } else {
                // build new context
                context = Context.newBuilder(model).resolver(MapValueResolver.INSTANCE,
                        JavaBeanValueResolver.INSTANCE, FieldValueResolver.INSTANCE, MethodValueResolver.INSTANCE)
                        .build();
            }

            // rendering it
            writer.text(out -> template.apply(context, out));
        }

        @Override
        public String toString() {
            return name();
        }
    }

    private final Handlebars hbs;

    public Hbs(final Handlebars handlebars) {
        this.hbs = requireNonNull(handlebars, "A handlebars instance is required.");
    }

    public Hbs() {
        this(new Handlebars(new ClassPathTemplateLoader("/", ".html")));
    }

    public Hbs doWith(final Consumer<Handlebars> block) {
        requireNonNull(block, "A hbs block is required.").accept(hbs);
        return this;
    };

    @Override
    public void configure(final Env mode, final Config config, final Binder binder) {

        // cache
        if ("dev".equals(mode.name()) || config.getString("hbs.cache").isEmpty()) {
            // noop cache
            hbs.with(NullTemplateCache.INSTANCE);
        } else {
            hbs.with(new GuavaTemplateCache(CacheBuilder.from(config.getString("hbs.cache")).build()));
        }

        binder.bind(Handlebars.class).toInstance(hbs);
        Engine engine = new Engine(hbs);

        Multibinder.newSetBinder(binder, Body.Formatter.class).addBinding().toInstance(engine);

        // direct accessf
        binder.bind(Key.get(View.Engine.class, Names.named(engine.name()))).toInstance(engine);
    }

    @Override
    public Config config() {
        return ConfigFactory.parseResources(getClass(), "hbs.conf");
    }

}