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 com.google.common.annotations.Beta;
  14 import java.util.Optional;
  15
  16 /**
  17  * Type-safe shim to ensure concrete {@link YangXPathMathSupport} implementations get handed properly-typed
  18  * YangNumberExprs.
  19  *
  20  * @param <N> Type of YangNumberExpr
  21  * @author Robert Varga
  22  */
  23 @Beta
  24 public abstract class AbstractYangXPathMathSupport<N extends YangNumberExpr> implements YangXPathMathSupport {
  25     private final Class<N> numberClass;
  26
  27     protected AbstractYangXPathMathSupport(final Class<N> numberClass) {
  28         this.numberClass = requireNonNull(numberClass);
  29     }
  30
  31     @Override
  32     public final N negateNumber(final YangNumberExpr number) {
  33         checkArgument(numberClass.isInstance(requireNonNull(number)), "Expected %s have %s", numberClass, number);
  34         return doNegateNumber(numberClass.cast(number));
  35     }
  36
  37     @Override
  38     public final Optional<YangExpr> tryEvaluate(final YangBinaryOperator operator, final YangNumberExpr left,
  39             final YangNumberExpr right) {
  40         if (!numberClass.isInstance(left) || !numberClass.isInstance(right)) {
  41             requireNonNull(operator);
  42             requireNonNull(left);
  43             requireNonNull(right);
  44             return Optional.empty();
  45         }
  46
  47         return Optional.of(doEvaluate(requireNonNull(operator), numberClass.cast(left), numberClass.cast(right)));
  48     }
  49
  50     /**
  51      * Create a {@link YangNumberExpr} representing the negated value of a number.
  52      *
  53      * @param number input number
  54      * @return negated number expression
  55      */
  56     protected abstract N doNegateNumber(N number);
  57
  58     /**
  59      * Evaluate an  operator and its left- and right-handside.
  60      *
  61      * @param operator Operator to apply
  62      * @param left Left hand-side
  63      * @param right Right hand-side
  64      * @return Evaluation result
  65      */
  66     protected abstract YangExpr doEvaluate(YangBinaryOperator operator, N left, N right);
  67 }