NewlineCheck.java

/*
 * Sonar XML Plugin
 * Copyright (C) 2010 Matthijs Galesloot
 * dev@sonar.codehaus.org
 *
 * 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 org.sonar.plugins.xml.checks;

import org.apache.commons.lang.StringUtils;
import org.sonar.check.Cardinality;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.plugins.xml.parsers.SaxParser;
import org.w3c.dom.Document;
import org.w3c.dom.Node;

/**
 * Perform check for newline after elements.
 * 
 * @author Matthijs Galesloot
 * @since 1.0
 */
@Rule(key = "NewlineCheck", name = "Newline Check", description = "Newline Check", priority = Priority.MINOR,
    cardinality = Cardinality.SINGLE)
public class NewlineCheck extends AbstractPageCheck {

  /**
   * Validate newlines for node.
   */
  private void validateNewline(Node node) {

    // check if we have a newline after the elements and after each childelement.
    boolean newline = false;
    Node lastChild = null;

    for (Node child = node.getFirstChild(); child != null; child = child.getNextSibling()) {
      switch (child.getNodeType()) {
        case Node.COMMENT_NODE:
        case Node.ELEMENT_NODE:
          // check if there is a new node before we have had any newlines.
          if ( !newline) {
            createViolation(SaxParser.getLineNumber(child), "Node should be on the next line");
          } else {
            newline = false;
          }
          lastChild = child;
          break;
        case Node.TEXT_NODE:
          // newline check is OK if there is non whitespace or the whitespace contains a newline 
          if ( !StringUtils.isWhitespace(child.getTextContent()) || child.getTextContent().contains("\n")) {
            newline = true;
          }
          break;
        default:
          break;
      }
    }

    // validate first last child.
    validateLastChild(newline, lastChild);

    // check the child elements
    for (Node child = node.getFirstChild(); child != null; child = child.getNextSibling()) {
      if (child.getNodeType() == Node.ELEMENT_NODE) {
        validateNewline(child);
      }
    }
  }

  private void validateLastChild(boolean newlineAfterLastChild, Node lastChild) {
    if ( !newlineAfterLastChild && lastChild != null) {
      createViolation(SaxParser.getLineNumber(lastChild), "Missing newline after last element");
    }
  }

  @Override
  public void validate(XmlSourceCode xmlSourceCode) {
    setWebSourceCode(xmlSourceCode);

    Document document = getWebSourceCode().getDocument(false);
    if (document != null && document.getDocumentElement() != null) {
      validateNewline(document.getDocumentElement());
    }
  }
}