component-dsl/src/main/java/org/apache/aries/component/dsl/internal/OSGiImpl.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.OSGi;
import org.apache.aries.component.dsl.OSGiRunnable;
import org.apache.aries.component.dsl.Publisher;
import org.apache.aries.component.dsl.OSGiResult;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Filter;
import org.osgi.framework.InvalidSyntaxException;

/**
 * @author Carlos Sierra Andrés
 */
public class OSGiImpl<T> implements OSGi<T> {

	protected OSGiImpl(OSGiRunnable<T> operation) {
		_operation = operation;
	}

	public static <T> OSGi<T> create(OSGiRunnable<T> runnable) {
		return new OSGiImpl<>(
			(ec, op) -> new OSGiResultImpl(runnable.run(ec, op)));
	}

	@Override
	public OSGiResult run(ExecutionContext executionContext) {
		return run(executionContext, x -> NOOP);
	}

	public OSGiResult run(
		ExecutionContext executionContext, Publisher<? super T> op) {

		return _operation.run(executionContext, op);
	}

	static Filter buildFilter(
		ExecutionContext executionContext, String filterString, Class<?> clazz) {

		Filter filter;

		String string = buildFilterString(filterString, clazz);

		try {
			filter = executionContext.getBundleContext().createFilter(string);
		}
		catch (InvalidSyntaxException e) {
			throw new RuntimeException(e);
		}

		return filter;
	}

	static String buildFilterString(String filterString, Class<?> clazz) {
		if (filterString == null && clazz == null) {
			throw new IllegalArgumentException(
				"Both filterString and clazz can't be null");
		}

		StringBuilder stringBuilder = new StringBuilder();

		if (filterString != null) {
			stringBuilder.append(filterString);
		}

		if (clazz != null) {
			boolean extend = !(stringBuilder.length() == 0);
			if (extend) {
				stringBuilder.insert(0, "(&");
			}

			stringBuilder.
				append("(objectClass=").
				append(clazz.getName()).
				append(")");

			if (extend) {
				stringBuilder.append(")");
			}

		}

		return stringBuilder.toString();
	}

	OSGiRunnable<T> _operation;

}