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   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
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   *
   *    https://www.apache.org/licenses/LICENSE-2.0
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  package org.apache.cayenne.exp.parser;
  
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.cayenne.exp.Expression;
  import org.apache.cayenne.util.ConversionUtil;
  
  /**
   * "Not" expression.
   * 
   * @since 1.1
   */
  public class ASTNot extends AggregateConditionNode {
  
  	private static final long serialVersionUID = 7418894098531106347L;
  
  	ASTNot(int id) {
  		super(id);
  	}
  
  	public ASTNot() {
  		super(ExpressionParserTreeConstants.JJTNOT);
  	}
  
  	public ASTNot(Node expression) {
  		super(ExpressionParserTreeConstants.JJTNOT);
  		jjtAddChild(expression, 0);
  		connectChildren();
  	}
  
  	@Override
  	protected Object evaluateNode(Object o) throws Exception {
  		int len = jjtGetNumChildren();
  		if (len == 0) {
  			return Boolean.FALSE;
  		}
  
  		Object o1 = evaluateChild(0, o);
  		if (o1 == null) {
  			return null;
  		}
  
  		return ConversionUtil.toBoolean(o1) ? Boolean.FALSE : Boolean.TRUE;
  	}
  
  	/**
  	 * Creates a copy of this expression node, without copying children.
  	 */
  	@Override
  	public Expression shallowCopy() {
  		return new ASTNot(id);
  	}
  
      @Override
  	public int getType() {
  		return Expression.NOT;
  	}
  
  	/**
  	 * @since 4.0
  	 */
  	@Override
  	public void appendAsString(Appendable out) throws IOException {
  		out.append("not ");
  		super.appendAsString(out);
  	}
  
      /**
       * @since 4.0
       */
      @Override
      public void appendAsEJBQL(List<Object> parameterAccumulator, Appendable out, String rootId) throws IOException {
          out.append("not ");
          super.appendAsEJBQL(parameterAccumulator, out, rootId);
      }
  
  	@Override
  	protected String getExpressionOperator(int index) {
  		throw new UnsupportedOperationException("No operator for '" + ExpressionParserTreeConstants.jjtNodeName[id] + "'");
  	}
  }
  