/**
 * This file is part of Eclipse Steady.
 *
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
 */
package org.eclipse.steady.java.monitor;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.configuration.Configuration;
import org.apache.logging.log4j.Logger;
import org.eclipse.steady.core.util.CoreConfiguration;
import org.eclipse.steady.shared.util.VulasConfiguration;

/**
 * Creates implementations of {@link IInstrumentor} for all classes specified via the
 * configuration option {@link CoreConfiguration#INSTR_CHOOSEN_INSTR}.
 */
public class InstrumentorFactory {

  private static final Logger log =
      org.apache.logging.log4j.LogManager.getLogger(InstrumentorFactory.class);

  private static List<IInstrumentor> instrumentors = null;

  /**
   * Creates and returns implementations of {@link IInstrumentor} for all classes specified via the
   * configuration option {@link CoreConfiguration#INSTR_CHOOSEN_INSTR}.
   * Those will be looped during static and dynamic instrumentation, e.g., in the classes
   * {@link ExecutionMonitor} and {@link ClassVisitor}.
   *
   * @return a {@link java.util.List} object.
   */
  public static synchronized List<IInstrumentor> getInstrumentors() {
    if (instrumentors == null) {
      instrumentors = new ArrayList<IInstrumentor>();
      final Configuration cfg = VulasConfiguration.getGlobal().getConfiguration();
      final String[] instrumentors = cfg.getStringArray(CoreConfiguration.INSTR_CHOOSEN_INSTR);
      for (String name : instrumentors) {
        final AbstractInstrumentor i = InstrumentorFactory.getInstrumentor(name);
        if (i != null) InstrumentorFactory.instrumentors.add(i);
      }
    }
    return instrumentors;
  }

  private static AbstractInstrumentor getInstrumentor(String _name) {
    AbstractInstrumentor i = null;
    try {
      final Class cls = Class.forName(_name);
      i = (AbstractInstrumentor) cls.getDeclaredConstructor().newInstance();
    } catch (Throwable e) {
      InstrumentorFactory.log.error(
          "Error while creating instrumentor of class [" + _name + "]: " + e.getMessage(), e);
    }
    return i;
  }
}
