and.java

java1.6众多例子参考

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * 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.
 */
/*
 * $Id: And.java,v 1.2.4.1 2005/09/14 21:31:42 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.operations;

import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XBoolean;
import com.sun.org.apache.xpath.internal.objects.XObject;

/**
 * The 'and' operation expression executer.
 */
public class And extends Operation
{
    static final long serialVersionUID = 392330077126534022L;

  /**
   * AND two expressions and return the boolean result. Override
   * superclass method for optimization purposes.
   *
   * @param xctxt The runtime execution context.
   *
   * @return {@link com.sun.org.apache.xpath.internal.objects.XBoolean#S_TRUE} or 
   * {@link com.sun.org.apache.xpath.internal.objects.XBoolean#S_FALSE}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {

    XObject expr1 = m_left.execute(xctxt);

    if (expr1.bool())
    {
      XObject expr2 = m_right.execute(xctxt);

      return expr2.bool() ? XBoolean.S_TRUE : XBoolean.S_FALSE;
    }
    else
      return XBoolean.S_FALSE;
  }
  
  /**
   * Evaluate this operation directly to a boolean.
   *
   * @param xctxt The runtime execution context.
   *
   * @return The result of the operation as a boolean.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean bool(XPathContext xctxt)
          throws javax.xml.transform.TransformerException
  {
    return (m_left.bool(xctxt) && m_right.bool(xctxt));
  }

}