/*
    * Portions of this software was developed by employees of the National Institute
    * of Standards and Technology (NIST), an agency of the Federal Government and is
    * being made available as a public service. Pursuant to title 17 United States
    * Code Section 105, works of NIST employees are not subject to copyright
    * protection in the United States. This software may be subject to foreign
    * copyright. Permission in the United States and in foreign countries, to the
    * extent that NIST may hold copyright, to use, copy, modify, create derivative
    * works, and distribute this software and its documentation without fee is hereby
   * granted on a non-exclusive basis, provided that this notice and disclaimer
   * of warranty appears in all copies.
   *
   * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
   * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
   * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
   * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
   * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
   * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
   * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
   * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
   * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
   * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
   * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
   */
  
  package gov.nist.secauto.metaschema.core.model.constraint;
  
  import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
  import gov.nist.secauto.metaschema.core.util.CollectionUtil;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  public class DefaultIndex implements IIndex {
    @NonNull
    private final List<IKeyField> keyFields;
    @NonNull
    private final Map<List<String>, INodeItem> keyToItemMap = new ConcurrentHashMap<>();
  
    /**
     * Construct a new index.
     *
     * @param keyFields
     *          the key field components to use to generate keys by default
     */
    protected DefaultIndex(@NonNull List<? extends IKeyField> keyFields) {
      this.keyFields = CollectionUtil.unmodifiableList(new ArrayList<>(keyFields));
    }
  
    @Override
    public List<IKeyField> getKeyFields() {
      return keyFields;
    }
  
    @Override
    public INodeItem put(@NonNull INodeItem item, @NonNull List<String> key) {
      INodeItem oldItem = null;
      if (!IIndex.isAllNulls(key)) {
        // only add keys with some information (values)
        oldItem = keyToItemMap.put(key, item);
      }
      return oldItem;
    }
  
    @Override
    public INodeItem get(List<String> key) {
      if (getKeyFields().size() != key.size()) {
        throw new IllegalArgumentException("Provided key is not the same size as the index requires.");
      }
      return keyToItemMap.get(key);
    }
  }