FnCompare.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.
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package gov.nist.secauto.metaschema.core.metapath.function.library;

import gov.nist.secauto.metaschema.core.metapath.DynamicContext;
import gov.nist.secauto.metaschema.core.metapath.ISequence;
import gov.nist.secauto.metaschema.core.metapath.MetapathConstants;
import gov.nist.secauto.metaschema.core.metapath.function.FunctionUtils;
import gov.nist.secauto.metaschema.core.metapath.function.IArgument;
import gov.nist.secauto.metaschema.core.metapath.function.IFunction;
import gov.nist.secauto.metaschema.core.metapath.item.IItem;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IIntegerItem;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IStringItem;
import gov.nist.secauto.metaschema.core.util.ObjectUtils;

import java.util.List;

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

public class FnCompare {

  @NonNull
  static final IFunction SIGNATURE = IFunction.builder()
      .name("compare")
      .namespace(MetapathConstants.NS_XPATH_FUNCTIONS)
      .deterministic()
      .contextDependent()
      .focusIndependent()
      .argument(IArgument.newBuilder()
          .name("comparand1")
          .type(IStringItem.class)
          .zeroOrOne()
          .build())
      .argument(IArgument.newBuilder()
          .name("comparand2")
          .type(IStringItem.class)
          .zeroOrOne()
          .build())
      .returnType(IIntegerItem.class)
      .returnZeroOrOne()
      .functionHandler(FnCompare::execute)
      .build();

  @SuppressWarnings("unused")
  @NonNull
  private static ISequence<IIntegerItem> execute(
      @NonNull IFunction function,
      @NonNull List<ISequence<?>> arguments,
      @NonNull DynamicContext dynamicContext,
      IItem focus) {
    IStringItem comparand1 = FunctionUtils.getFirstItem(
        FunctionUtils.asType(ObjectUtils.requireNonNull(arguments.get(0))), true);

    IStringItem comparand2 = FunctionUtils.getFirstItem(
        FunctionUtils.asType(ObjectUtils.requireNonNull(arguments.get(1))), true);

    ISequence<IIntegerItem> retval;
    if (comparand1 == null || comparand2 == null) {
      retval = ISequence.empty();
    } else {
      IIntegerItem result = comparand1.compare(comparand2);
      retval = ISequence.of(result);
    }
    return retval;
  }
}