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