FnExists.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
* 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.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.IBooleanItem;
import gov.nist.secauto.metaschema.core.util.ObjectUtils;
import java.util.List;
import edu.umd.cs.findbugs.annotations.NonNull;
public final class FnExists {
@NonNull
static final IFunction SIGNATURE = IFunction.builder()
.name("exists")
.namespace(MetapathConstants.NS_XPATH_FUNCTIONS)
.deterministic()
.contextIndependent()
.focusIndependent()
.argument(IArgument.newBuilder()
.name("arg")
.type(IItem.class)
.zeroOrMore()
.build())
.returnType(IBooleanItem.class)
.returnOne()
.functionHandler(FnExists::execute)
.build();
private FnExists() {
// disable construction
}
@SuppressWarnings("unused")
@NonNull
private static ISequence<IBooleanItem> execute(@NonNull IFunction function,
@NonNull List<ISequence<?>> arguments,
@NonNull DynamicContext dynamicContext,
IItem focus) {
ISequence<?> items = FunctionUtils.asType(ObjectUtils.requireNonNull(arguments.get(0)));
return ISequence.of(fnExists(items));
}
/**
* Identify if there is at least one item in the {@code sequence}.
*
* @param sequence
* the sequence to check
* @return {@code true} if the sequence contains at least one item, or
* {@code false} otherwise
*/
public static IBooleanItem fnExists(ISequence<?> sequence) {
return IBooleanItem.valueOf(!sequence.isEmpty());
}
}