library/src/main/java/com/datatorrent/lib/math/AbstractXmlKeyValueCartesianProduct.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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.datatorrent.lib.math;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * This operator extends the AbstractXmlCartesianProduct operator and implements the node value 
 * as a key value pair of node name and the node's text value.
 * 
 * @displayName Abstract XML Key Value Cartesian Product
 * @category Math
 * @tags cartesian product, xml, multiple products, key value
 * @since 1.0.1
 */
public abstract class AbstractXmlKeyValueCartesianProduct<T> extends AbstractXmlCartesianProduct<T>
{
  @Override
  public String getValue(Node node)
  {
    return node.getNodeName() + "=" + getTextValue(node);
  }

  @Override
  public boolean isValueNode(Node n) {
    return isTextContainerNode(n);
  }

  private boolean isTextContainerNode(Node n)
  {
    boolean container = false;
    NodeList childNodes = n.getChildNodes();
    if (childNodes.getLength() == 1) {
      Node firstChild = childNodes.item(0);
      if (firstChild.getNodeType() == Node.TEXT_NODE) {
        container = true;
      }
    }
    return container;
  }

  protected String getTextValue(Node n)
  {
    String text = null;
    NodeList childNodes = n.getChildNodes();
    if (childNodes.getLength() == 1) {
      Node firstChild = childNodes.item(0);
      text = firstChild.getNodeValue();
    }
    return text;
  }
}