ValueComparison.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;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IAnyAtomicItem;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IBooleanItem;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
class ValueComparison
extends AbstractComparison {
/**
* Create a new value comparison expression.
*
* @param left
* the expression to compare against
* @param operator
* the comparison operator
* @param right
* the expression to compare with
*/
protected ValueComparison(@NonNull IExpression left, @NonNull Operator operator, @NonNull IExpression right) {
super(left, operator, right);
}
@Override
public <RESULT, CONTEXT> RESULT accept(IExpressionVisitor<RESULT, CONTEXT> visitor, CONTEXT context) {
return visitor.visitValueComparison(this, context);
}
@Override
public ISequence<? extends IBooleanItem> accept(DynamicContext dynamicContext, ISequence<?> focus) {
IAnyAtomicItem left = getFirstDataItem(getLeft().accept(dynamicContext, focus), false);
IAnyAtomicItem right = getFirstDataItem(getRight().accept(dynamicContext, focus), false);
return resultOrEmpty(left, right);
}
/**
* Compare the two atomic items.
*
* @param leftItem
* the first item to compare
* @param rightItem
* the second item to compare
* @return a or an empty {@link ISequence} if either item is {@code null}
*/
@NonNull
protected ISequence<? extends IBooleanItem> resultOrEmpty(@Nullable IAnyAtomicItem leftItem,
@Nullable IAnyAtomicItem rightItem) {
ISequence<? extends IBooleanItem> retval;
if (leftItem == null || rightItem == null) {
retval = ISequence.empty();
} else {
IBooleanItem result = valueCompairison(leftItem, getOperator(), rightItem);
retval = ISequence.of(result);
}
return retval;
}
/**
* Compare the two items using the provided {@code operator}.
*
* @param leftItem
* the first item to compare
* @param operator
* the comparison operator
* @param rightItem
* the second item to compare
* @return the result of the comparison
*/
@NonNull
protected IBooleanItem valueCompairison(@NonNull IAnyAtomicItem leftItem, @NonNull Operator operator,
@NonNull IAnyAtomicItem rightItem) {
return compare(leftItem, operator, rightItem);
}
}