com.phloc.web.networkinterface.NetworkInterfaceUtils Maven / Gradle / Ivy

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/**
 * Copyright (C) 2006-2015 phloc systems
 * http://www.phloc.com
 * office[at]phloc[dot]com
 *
 * 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 com.phloc.web.networkinterface;

import java.net.NetworkInterface;
import java.util.ArrayList;
import java.util.List;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;

import com.phloc.commons.annotations.PresentForCodeCoverage;
import com.phloc.commons.collections.ContainerHelper;
import com.phloc.commons.tree.withid.DefaultTreeItemWithID;
import com.phloc.commons.tree.withid.unique.DefaultTreeWithGlobalUniqueID;

/**
 * Some utility methods for {@link NetworkInterface}
 * 
 * @author Philip Helger
 */
@Immutable
public final class NetworkInterfaceUtils
{
  @SuppressWarnings ("unused")
  @PresentForCodeCoverage
  private static final NetworkInterfaceUtils s_aInstance = new NetworkInterfaceUtils ();

  private NetworkInterfaceUtils ()
  {}

  /**
   * Create a hierarchical tree of the network interfaces.
   * 
   * @return The created tree and never null.
   * @throws IllegalStateException
   *         In case an internal error occurred.
   */
  @Nonnull
  public static DefaultTreeWithGlobalUniqueID  createNetworkInterfaceTree ()
  {
    final DefaultTreeWithGlobalUniqueID  ret = new DefaultTreeWithGlobalUniqueID  ();

    // Build basic level - all IFs without a parent
    final List  aNonRootNIs = new ArrayList  ();
    try
    {
      for (final NetworkInterface aNI : ContainerHelper.getIterator (NetworkInterface.getNetworkInterfaces ()))
        if (aNI.getParent () == null)
          ret.getRootItem ().createChildItem (aNI.getName (), aNI);
        else
          aNonRootNIs.add (aNI);
    }
    catch (final Throwable t)
    {
      throw new IllegalStateException ("Failed to get all network interfaces", t);
    }

    int nNotFound = 0;
    while (!aNonRootNIs.isEmpty ())
    {
      final NetworkInterface aNI = aNonRootNIs.remove (0);
      final DefaultTreeItemWithID  aParentItem = ret.getItemWithID (aNI.getParent ()
                                                                                                 .getName ());
      if (aParentItem != null)
      {
        // We found the parent
        aParentItem.createChildItem (aNI.getName (), aNI);

        // Reset counter
        nNotFound = 0;
      }
      else
      {
        // Add again at the end
        aNonRootNIs.add (aNI);

        // Parent not found
        nNotFound++;

        // We tried too many times without success - we iterated the whole
        // remaining list and found no parent tree item
        if (nNotFound > aNonRootNIs.size ())
          throw new IllegalStateException ("Seems like we have a data structure inconsistency! Remaining are: " +
                                           aNonRootNIs);
      }
    }
    return ret;
  }
}