AbstractBasicArithmeticExpression.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
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* 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
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package gov.nist.secauto.metaschema.core.metapath;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IAnyAtomicItem;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
abstract class AbstractBasicArithmeticExpression
extends AbstractArithmeticExpression<IAnyAtomicItem> {
/**
* An expression that represents a basic arithmetic operation on two values.
*
* @param left
* the first item
* @param right
* the second item
*/
public AbstractBasicArithmeticExpression(@NonNull IExpression left, @NonNull IExpression right) {
super(left, right, IAnyAtomicItem.class);
}
@Override
public Class<IAnyAtomicItem> getBaseResultType() {
return IAnyAtomicItem.class;
}
@Override
public ISequence<? extends IAnyAtomicItem> accept(DynamicContext dynamicContext, ISequence<?> focus) {
IAnyAtomicItem leftItem = getFirstDataItem(getLeft().accept(dynamicContext, focus), true);
IAnyAtomicItem rightItem = getFirstDataItem(getRight().accept(dynamicContext, focus), true);
return resultOrEmpty(leftItem, rightItem);
}
/**
* Setup the operation on two atomic items.
*
* @param leftItem
* the first item
* @param rightItem
* the second item
* @return the result of the operation or an empty {@link ISequence} if either
* item is {@code null}
*/
@NonNull
protected ISequence<? extends IAnyAtomicItem> resultOrEmpty(
@Nullable IAnyAtomicItem leftItem,
@Nullable IAnyAtomicItem rightItem) {
ISequence<? extends IAnyAtomicItem> retval;
if (leftItem == null || rightItem == null) {
retval = ISequence.empty();
} else {
IAnyAtomicItem result = operation(leftItem, rightItem);
retval = ISequence.of(result);
}
return retval;
}
/**
* Performs the arithmetic operation using the two provided values.
*
* @param left
* the first item
* @param right
* the second item
* @return the result of the operation
*/
@NonNull
protected abstract IAnyAtomicItem operation(@NonNull IAnyAtomicItem left, @NonNull IAnyAtomicItem right);
}