yang/yang-xpath-api/src/main/java/org/opendaylight/yangtools/yang/xpath/api/AbstractYangXPathMathSupport.java

   1 /*
   2  * Copyright (c) 2019 Pantheon Technologies, s.r.o.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.yangtools.yang.xpath.api;
   9
  10 import static com.google.common.base.Preconditions.checkArgument;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import java.util.Optional;
  14
  15 abstract class AbstractYangXPathMathSupport<N extends YangNumberExpr<N, ?>> implements YangXPathMathSupport<N> {
  16     private final Class<N> numberClass;
  17
  18     AbstractYangXPathMathSupport(final Class<N> numberClass) {
  19         this.numberClass = requireNonNull(numberClass);
  20     }
  21
  22     @Override
  23     public final N negateNumber(final YangNumberExpr<?, ?> number) {
  24         checkArgument(numberClass.isInstance(requireNonNull(number)), "Expected %s have %s", numberClass, number);
  25         return doNegate(numberClass.cast(number));
  26     }
  27
  28
  29     @Override
  30     public final Optional<YangExpr> tryEvaluate(final YangBinaryOperator operator,
  31             final YangNumberExpr<?, ?> left, final YangNumberExpr<?, ?> right) {
  32         if (!numberClass.isInstance(left) || !numberClass.isInstance(right)) {
  33             requireNonNull(operator);
  34             requireNonNull(left);
  35             requireNonNull(right);
  36             return Optional.empty();
  37         }
  38
  39         return Optional.of(evaluate(requireNonNull(operator), numberClass.cast(left), numberClass.cast(right)));
  40     }
  41
  42     abstract N doNegate(N number);
  43
  44     /**
  45      * Evaluate an  operator and its left- and right-handside.
  46      *
  47      * @param operator Operator to apply
  48      * @param left Left hand-side
  49      * @param right Right hand-side
  50      * @return Evaluation result
  51      */
  52     abstract YangExpr evaluate(YangBinaryOperator operator, N left, N right);
  53 }