AbstractDataTypeProvider.java

/*
 * 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
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 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
 */

package gov.nist.secauto.metaschema.core.datatype;

import gov.nist.secauto.metaschema.core.datatype.adapter.MetaschemaDataTypeProvider;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import edu.umd.cs.findbugs.annotations.NonNull;

/**
 * A base implementation of an {@link IDataTypeProvider}, supporting dynamic
 * loading of Metaschema data type extensions at runtime.
 * <p>
 * The {@link MetaschemaDataTypeProvider} class provides an example of how to
 * use this class to provide new data types.
 */
public abstract class AbstractDataTypeProvider implements IDataTypeProvider {
  private final List<IDataTypeAdapter<?>> library = new LinkedList<>();

  @SuppressWarnings("null")
  @Override
  public List<? extends IDataTypeAdapter<?>> getJavaTypeAdapters() {
    synchronized (this) {
      return Collections.unmodifiableList(library);
    }
  }

  /**
   * Register the provided {@code adapter} with the type system.
   *
   * @param adapter
   *          the adapter to register
   * @throws IllegalArgumentException
   *           if another type adapter has no name
   */
  protected void registerDatatype(@NonNull IDataTypeAdapter<?> adapter) {
    if (adapter.getNames().size() == 0) {
      throw new IllegalArgumentException("The adapter has no name: " + adapter.getClass().getName());
    }
    synchronized (this) {
      library.add(adapter);
    }
  }
}