/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.elasticsearch.common.inject;

import org.elasticsearch.common.inject.internal.Errors;
import org.elasticsearch.common.inject.internal.ErrorsException;
import org.elasticsearch.common.inject.internal.InternalContext;
import org.elasticsearch.common.inject.internal.InternalFactory;
import org.elasticsearch.common.inject.internal.ToStringBuilder;
import org.elasticsearch.common.inject.spi.Dependency;

/**
 * A placeholder which enables us to swap in the real factory once the injector is created.
 */
class FactoryProxy<T> implements InternalFactory<T>, BindingProcessor.CreationListener {

    private final InjectorImpl injector;
    private final Key<T> key;
    private final Key<? extends T> targetKey;
    private final Object source;

    private InternalFactory<? extends T> targetFactory;

    FactoryProxy(InjectorImpl injector, Key<T> key, Key<? extends T> targetKey, Object source) {
        this.injector = injector;
        this.key = key;
        this.targetKey = targetKey;
        this.source = source;
    }

    @Override
    public void notify(final Errors errors) {
        try {
            targetFactory = injector.getInternalFactory(targetKey, errors.withSource(source));
        } catch (ErrorsException e) {
            errors.merge(e.getErrors());
        }
    }

    @Override
    public T get(Errors errors, InternalContext context, Dependency<?> dependency)
            throws ErrorsException {
        return targetFactory.get(errors.withSource(targetKey), context, dependency);
    }

    @Override
    public String toString() {
        return new ToStringBuilder(FactoryProxy.class)
                .add("key", key)
                .add("provider", targetFactory)
                .toString();
    }
}