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 static final long serialVersionUID = 1L;
  26
  27     private final Class<N> numberClass;
  28
  29     protected AbstractYangXPathMathSupport(final Class<N> numberClass) {
  30         this.numberClass = requireNonNull(numberClass);
  31     }
  32
  33     @Override
  34     public final N negateNumber(final YangNumberExpr number) {
  35         checkArgument(numberClass.isInstance(requireNonNull(number)), "Expected %s have %s", numberClass, number);
  36         return doNegateNumber(numberClass.cast(number));
  37     }
  38
  39     @Override
  40     public final Optional<YangExpr> tryEvaluate(final YangBinaryOperator operator, final YangNumberExpr left,
  41             final YangNumberExpr right) {
  42         if (!numberClass.isInstance(left) || !numberClass.isInstance(right)) {
  43             requireNonNull(operator);
  44             requireNonNull(left);
  45             requireNonNull(right);
  46             return Optional.empty();
  47         }
  48
  49         return Optional.of(doEvaluate(requireNonNull(operator), numberClass.cast(left), numberClass.cast(right)));
  50     }
  51
  52     /**
  53      * Create a {@link YangNumberExpr} representing the negated value of a number.
  54      *
  55      * @param number input number
  56      * @return negated number expression
  57      */
  58     protected abstract N doNegateNumber(N number);
  59
  60     /**
  61      * Evaluate an  operator and its left- and right-handside.
  62      *
  63      * @param operator Operator to apply
  64      * @param left Left hand-side
  65      * @param right Right hand-side
  66      * @return Evaluation result
  67      */
  68     protected abstract YangExpr doEvaluate(YangBinaryOperator operator, N left, N right);
  69
  70     protected abstract Object readResolve();
  71 }