001/*
002 * Portions of this software was developed by employees of the National Institute
003 * of Standards and Technology (NIST), an agency of the Federal Government and is
004 * being made available as a public service. Pursuant to title 17 United States
005 * Code Section 105, works of NIST employees are not subject to copyright
006 * protection in the United States. This software may be subject to foreign
007 * copyright. Permission in the United States and in foreign countries, to the
008 * extent that NIST may hold copyright, to use, copy, modify, create derivative
009 * works, and distribute this software and its documentation without fee is hereby
010 * granted on a non-exclusive basis, provided that this notice and disclaimer
011 * of warranty appears in all copies.
012 *
013 * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
014 * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
015 * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
016 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
017 * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
018 * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
019 * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
020 * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
021 * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
022 * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
023 * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
024 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
025 */
026
027package gov.nist.secauto.metaschema.core.metapath.function.library;
028
029import gov.nist.secauto.metaschema.core.metapath.DynamicContext;
030import gov.nist.secauto.metaschema.core.metapath.ISequence;
031import gov.nist.secauto.metaschema.core.metapath.function.FunctionUtils;
032import gov.nist.secauto.metaschema.core.metapath.function.IArgument;
033import gov.nist.secauto.metaschema.core.metapath.function.IFunction;
034import gov.nist.secauto.metaschema.core.metapath.function.IFunctionExecutor;
035import gov.nist.secauto.metaschema.core.metapath.item.IItem;
036import gov.nist.secauto.metaschema.core.metapath.item.atomic.IAnyAtomicItem;
037import gov.nist.secauto.metaschema.core.util.ObjectUtils;
038
039import java.net.URI;
040import java.util.List;
041
042import edu.umd.cs.findbugs.annotations.NonNull;
043
044public final class CastFunction<ITEM extends IAnyAtomicItem> implements IFunctionExecutor {
045  @NonNull
046  private final ICastExecutor<ITEM> castExecutor;
047
048  @NonNull
049  static <ITEM extends IAnyAtomicItem> IFunction signature(
050      @NonNull URI namespace,
051      @NonNull String name,
052      @NonNull Class<ITEM> resulingAtomicType,
053      @NonNull ICastExecutor<ITEM> executor) {
054    return signature(
055        ObjectUtils.notNull(namespace.toASCIIString()),
056        name,
057        resulingAtomicType,
058        executor);
059  }
060
061  @NonNull
062  static <ITEM extends IAnyAtomicItem> IFunction signature(
063      @NonNull String namespace,
064      @NonNull String name,
065      @NonNull Class<ITEM> resulingAtomicType,
066      @NonNull ICastExecutor<ITEM> executor) {
067    return IFunction.builder()
068        .name(name)
069        .namespace(namespace)
070        .argument(IArgument.newBuilder()
071            .name("arg1")
072            .type(IAnyAtomicItem.class)
073            .zeroOrOne()
074            .build())
075        .returnType(resulingAtomicType)
076        .returnZeroOrOne()
077        .functionHandler(newCastExecutor(executor))
078        .build();
079  }
080
081  @NonNull
082  private static <ITEM extends IAnyAtomicItem> CastFunction<ITEM>
083      newCastExecutor(@NonNull ICastExecutor<ITEM> executor) {
084    return new CastFunction<>(executor);
085  }
086
087  private CastFunction(@NonNull ICastExecutor<ITEM> castExecutor) {
088    this.castExecutor = castExecutor;
089  }
090
091  @Override
092  public ISequence<ITEM> execute(@NonNull IFunction function,
093      @NonNull List<ISequence<?>> arguments,
094      @NonNull DynamicContext dynamicContext,
095      IItem focus) {
096
097    ISequence<? extends IAnyAtomicItem> arg = FunctionUtils.asType(
098        ObjectUtils.notNull(arguments.get(0)));
099
100    IAnyAtomicItem item = FunctionUtils.getFirstItem(arg, true);
101    if (item == null) {
102      return ISequence.empty(); // NOPMD - readability
103    }
104
105    ITEM castItem = castExecutor.cast(item);
106    return ISequence.of(castItem);
107  }
108
109  @FunctionalInterface
110  public interface ICastExecutor<ITEM extends IAnyAtomicItem> {
111    /**
112     * Cast the provided {@code item}.
113     *
114     * @param item
115     *          the item to cast
116     * @return the item cast to the appropriate type
117     */
118    @NonNull
119    ITEM cast(@NonNull IAnyAtomicItem item);
120  }
121}