org.fuwjax.oss.inject.Scope Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of wheatgrass Show documentation
Healthy Dependency Injection
There is a newer version: 1.44
/*
 * Copyright (C) 2015 fuwjax.org ([email protected])
 *
 * 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 org.fuwjax.oss.inject;

import static org.fuwjax.oss.util.function.Functions.function;

import java.util.HashMap;
import java.util.Map;

import org.fuwjax.oss.generic.GenericMember;
import org.fuwjax.oss.util.Arrays2;
import org.fuwjax.oss.util.Iterables;
import org.fuwjax.oss.util.RunWrapException;

/**
 * Created by fuwjax on 2/17/15.
 */
public class Scope implements ObjectFactory {
	private final Map objects = new HashMap<>();
	private final InjectorStrategy injector;

	public Scope(final InjectorStrategy injector) {
		this.injector = injector;
		objects.put(new BindConstraint(ObjectFactory.class), this);
	}

	@Override
	public Object get(final BindConstraint constraint) throws ReflectiveOperationException {
		Object object = objects.get(constraint);
		if (object == null) {
			object = binding(constraint).get(this);
			objects.put(constraint, object);
		}
		return object;
	}

	@Override
	public void inject(final BindConstraint constraint, final Object target) throws ReflectiveOperationException {
		assert constraint != null;
		assert target != null;
		objects.put(constraint, target);
		inject(InjectSpec.of(constraint.type()), target);
	}

	public Object invoke(final Object target, final GenericMember member) throws ReflectiveOperationException {
		try {
			final Object[] args = Arrays2.transform(member.paramTypes(), new Object[0], function(t -> get(new BindConstraint(t))));
			return member.invoke(target, args);
		} catch (final RunWrapException e) {
			throw e.throwIf(ReflectiveOperationException.class);
		}
	}

	private Binding binding(final BindConstraint constraint) throws ReflectiveOperationException {
		final Binding binding = injector.bindingFor(constraint);
		if (binding == null) {
			throw new ReflectiveOperationException("No binding for " + constraint);
		}
		return binding;
	}

	public Object create(final BindConstraint constraint) throws ReflectiveOperationException {
		final InjectSpec spec = InjectSpec.of(constraint.type());
		final Object o = invoke(null, spec.constructor());
		objects.put(constraint, o);
		inject(spec, o);
		return o;
	}

	private void inject(final InjectSpec spec, final Object object) throws ReflectiveOperationException {
		for (final GenericMember member : Iterables.over(spec.members())) {
			invoke(object, member);
		}
	}

}