attic/yang-data-jaxen/src/main/java/org/opendaylight/yangtools/yang/data/jaxen/ExprWalker.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. and others.  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.data.jaxen;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import java.util.Optional;
  13 import org.jaxen.expr.AllNodeStep;
  14 import org.jaxen.expr.BinaryExpr;
  15 import org.jaxen.expr.CommentNodeStep;
  16 import org.jaxen.expr.Expr;
  17 import org.jaxen.expr.FilterExpr;
  18 import org.jaxen.expr.FunctionCallExpr;
  19 import org.jaxen.expr.LiteralExpr;
  20 import org.jaxen.expr.LocationPath;
  21 import org.jaxen.expr.NameStep;
  22 import org.jaxen.expr.NumberExpr;
  23 import org.jaxen.expr.PathExpr;
  24 import org.jaxen.expr.ProcessingInstructionNodeStep;
  25 import org.jaxen.expr.TextNodeStep;
  26 import org.jaxen.expr.UnaryExpr;
  27 import org.jaxen.expr.VariableReferenceExpr;
  28
  29 final class ExprWalker {
  30     private final ExprListener listener;
  31
  32     ExprWalker(final ExprListener listener) {
  33         this.listener = requireNonNull(listener);
  34     }
  35
  36     public void walk(final Expr expr) {
  37         if (expr instanceof BinaryExpr) {
  38             final BinaryExpr binary = (BinaryExpr) expr;
  39             listener.enterBinaryExpr(binary);
  40             walk(binary.getLHS());
  41             listener.visitOperator(Operator.forString(binary.getOperator()));
  42             walk(binary.getRHS());
  43             listener.exitBinaryExpr(binary);
  44         } else if (expr instanceof FilterExpr) {
  45             final FilterExpr filter = (FilterExpr) expr;
  46             listener.enterFilterExpr(filter);
  47             walk(expr);
  48             listener.exitFilterExpr(filter);
  49         } else if (expr instanceof FunctionCallExpr) {
  50             final FunctionCallExpr func = (FunctionCallExpr) expr;
  51             listener.enterFunctionCallExpr(func);
  52
  53             for (Object arg : func.getParameters()) {
  54                 walk((Expr) arg);
  55             }
  56
  57             listener.exitFunctionCallExpr(func);
  58         } else if (expr instanceof LiteralExpr) {
  59             listener.visitLiteralExpr((LiteralExpr) expr);
  60         } else if (expr instanceof LocationPath) {
  61             final LocationPath path = (LocationPath) expr;
  62             final Optional<StepListener> maybeListener = listener.enterLocationPath(path);
  63             if (maybeListener.isPresent()) {
  64                 final StepListener l = maybeListener.get();
  65                 for (Object step : path.getSteps()) {
  66                     if (step instanceof AllNodeStep) {
  67                         l.onAll((AllNodeStep) step);
  68                     } else if (step instanceof CommentNodeStep) {
  69                         l.onComment((CommentNodeStep) step);
  70                     } else if (step instanceof NameStep) {
  71                         l.onName((NameStep) step);
  72                     } else if (step instanceof ProcessingInstructionNodeStep) {
  73                         l.onProcessingInstruction((ProcessingInstructionNodeStep) step);
  74                     } else if (step instanceof TextNodeStep) {
  75                         l.onTest((TextNodeStep) step);
  76                     } else {
  77                         throw new IllegalArgumentException("Unsupported step " + step);
  78                     }
  79                 }
  80             }
  81
  82             listener.exitLocationPath(path);
  83         } else if (expr instanceof NumberExpr) {
  84             listener.visitNumberExpr((NumberExpr) expr);
  85         } else if (expr instanceof PathExpr) {
  86             final PathExpr path = (PathExpr) expr;
  87             listener.enterPathExpr(path);
  88             walk(path.getFilterExpr());
  89             walk(path.getLocationPath());
  90             listener.exitPathExpr(path);
  91         } else if (expr instanceof UnaryExpr) {
  92             final UnaryExpr unary = (UnaryExpr) expr;
  93             listener.enterNotExpr(unary);
  94             walk(unary.getExpr());
  95             listener.exitNotExpr(unary);
  96         } else if (expr instanceof VariableReferenceExpr) {
  97             listener.visitVariableReferenceExpr((VariableReferenceExpr) expr);
  98         } else {
  99             throw new IllegalArgumentException("Unsupported expression " + expr);
 100         }
 101     }
 102 }