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Convenient utility to build XML models by evaluating XPath expressions
There is a newer version: 2.3.9
/*
 * Copyright 2017-2021 Alex Simkin
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.github.simy4.xpath.expr;

import com.github.simy4.xpath.XmlBuilderException;
import com.github.simy4.xpath.navigator.Navigator;
import com.github.simy4.xpath.navigator.Node;
import com.github.simy4.xpath.view.AbstractViewVisitor;
import com.github.simy4.xpath.view.BooleanView;
import com.github.simy4.xpath.view.IterableNodeView;
import com.github.simy4.xpath.view.LiteralView;
import com.github.simy4.xpath.view.NodeView;
import com.github.simy4.xpath.view.NumberView;
import com.github.simy4.xpath.view.View;
import com.github.simy4.xpath.view.ViewVisitor;

import java.util.Iterator;

public class NotEqualsExpr extends AbstractOperationExpr {

  private static final long serialVersionUID = 1L;

  public NotEqualsExpr(Expr leftExpr, Expr rightExpr) {
    super(leftExpr, rightExpr);
  }

  @Override
  public  View resolve(
      Navigator navigator, View left, View right, boolean greedy)
      throws XmlBuilderException {
    boolean ne = 0 != left.compareTo(right);
    if (!ne && greedy) {
      ne = left.visit(new NotEqualsVisitor(navigator, right));
    }
    return BooleanView.of(ne);
  }

  @Override
  protected String operator() {
    return "!=";
  }

  private static final class NotEqualsVisitor
      extends AbstractViewVisitor {

    private final Navigator navigator;
    private final View right;

    private NotEqualsVisitor(Navigator navigator, View right) {
      this.navigator = navigator;
      this.right = right;
    }

    @Override
    public Boolean visit(IterableNodeView nodeSet) throws XmlBuilderException {
      final Iterator> iterator = nodeSet.iterator();
      final View negatedRight = right.visit(new ViewNegator());
      if (!iterator.hasNext() || right.toString().equals(negatedRight.toString())) {
        throw new XmlBuilderException("Unable to satisfy not equals criteria for: " + right);
      }
      while (iterator.hasNext()) {
        navigator.setText(iterator.next().getNode(), negatedRight.toString());
      }
      return true;
    }

    @Override
    protected Boolean returnDefault(View view) throws XmlBuilderException {
      throw new XmlBuilderException("Can not modify read-only node: " + view);
    }
  }

  private static final class ViewNegator implements ViewVisitor> {

    @Override
    public View visit(BooleanView bool) {
      return BooleanView.of(!bool.toBoolean());
    }

    @Override
    public View visit(IterableNodeView nodeSet) throws XmlBuilderException {
      final Iterator> iterator = nodeSet.iterator();
      if (!iterator.hasNext()) {
        throw new XmlBuilderException("Unable to satisfy not equals criteria for: " + nodeSet);
      }
      return new LiteralView(new StringBuilder(iterator.next().toString()).reverse().toString());
    }

    @Override
    public View visit(LiteralView literal) {
      return new LiteralView(new StringBuilder(literal.toString()).reverse().toString());
    }

    @Override
    public View visit(NumberView number) {
      return new NumberView(-number.toNumber());
    }
  }
}