component-dsl/src/main/java/org/apache/aries/component/dsl/internal/JustOSGiImpl.java

/*
 * 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.apache.aries.component.dsl.internal;


import org.apache.aries.component.dsl.OSGiResult;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.ListIterator;
import java.util.function.Supplier;

/**
 * @author Carlos Sierra Andrés
 */
public class JustOSGiImpl<T> extends OSGiImpl<T> {

    public JustOSGiImpl(Collection<T> t) {
        this(() -> t);
    }

    public JustOSGiImpl(Supplier<Collection<T>> supplier) {
        super((executionContext, op) -> {

            Collection<T> collection = supplier.get();
            ArrayList<OSGiResult> references = new ArrayList<>(collection.size());

            try {
                for (T t : collection) {
                    references.add(op.publish(t));
                }
            }
            catch (Exception e) {
                cleanUp(references);

                throw e;
            }

            return new OSGiResultImpl(
                () -> cleanUp(references),
                () -> references.stream().map(res -> res.update()).reduce(Boolean.FALSE, Boolean::logicalOr)
            );
        });
    }

    private static void cleanUp(ArrayList<OSGiResult> references) {
        ListIterator<OSGiResult> iterator =
            references.listIterator(references.size());

        while (iterator.hasPrevious()) {
            try {
                iterator.previous().run();
            }
            catch (Exception e) {
            }
        }
    }

    public JustOSGiImpl(T t) {
        this(() -> Collections.singletonList(t));
    }

}