DocumentsAssertionError.java

package org.tigris.juxy.util;

import org.w3c.dom.DocumentType;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.traversal.TreeWalker;

import java.util.Arrays;

/**
 * @author Pavel Sher
 */
public class DocumentsAssertionError extends AssertionError {
  private TreeWalker etw;
  private TreeWalker atw;
  private String message;

  public DocumentsAssertionError(TreeWalker etw, TreeWalker atw) {
    this.etw = etw;
    this.atw = atw;
    init();
  }

  private void init() {
    StringBuffer buf = new StringBuffer(100);
    buf.append("Documents differ, expected document:\n");
    appendDocument(buf, etw);
    buf.append("\nActual document:\n");
    appendDocument(buf, atw);
    message = buf.toString();
  }

  public String getMessage() {
    return message;
  }

  private void appendDocument(StringBuffer buf, TreeWalker tw) {
    Node startFrom = tw.getCurrentNode();
    if (hasParentElement(startFrom))
      startFrom = tw.parentNode();

    if (startFrom.getOwnerDocument() == null)
      startFrom = tw.nextNode();

    String delimiter = null;
    if (hasParentElement(startFrom))
      delimiter = "...";

    appendDelimiter(buf, delimiter);
    serialize(buf, tw, 0);
    appendDelimiter(buf, delimiter);
  }

  private boolean hasParentElement(Node startFrom) {
    if (startFrom == null || startFrom.getNodeType() == Node.DOCUMENT_NODE)
      return false;

    return startFrom.getParentNode() != null && startFrom.getParentNode().getNodeType() == Node.ELEMENT_NODE;
  }

  private void appendDelimiter(StringBuffer buf, String delimiter) {
    if (delimiter != null) {
      appendNewLine(buf);
      buf.append(delimiter).append('\n');
    }
  }

  private void serialize(StringBuffer buf, TreeWalker tw, int level) {
    char[] prefixChars = new char[level * 2];
    Arrays.fill(prefixChars, ' ');

    Node currentNode = tw.getCurrentNode();
    while (currentNode != null) {
      switch (currentNode.getNodeType()) {
        case Node.ELEMENT_NODE:
          appendNewLine(buf);
          appendPrefix(buf, prefixChars).append("<").append(currentNode.getNodeName());
          NamedNodeMap attrs = currentNode.getAttributes();
          for (int i = 0; i < attrs.getLength(); i++) {
            Node attr = attrs.item(i);
            // we will skip here xmlns attribute defining namespace of currentNode element
            // and write it later
            if (attr.getNodeName().startsWith("xmlns") && attr.getNodeValue().equals(currentNode.getNamespaceURI()))
              continue;
            buf.append(" ").append(attr.getNodeName()).append("=\"").append(getAttributeValue(attr)).append("\"");
          }

          if (currentNode.getNamespaceURI() != null) {
            buf.append(" xmlns");
            if (currentNode.getPrefix() != null)
              buf.append(':').append(currentNode.getPrefix());
            buf.append("=\"").append(currentNode.getNamespaceURI()).append("\"");
          }

          Node child = tw.firstChild();
          if (child == null) {
            buf.append("/>\n");
          } else {
            buf.append(">");
            serialize(buf, tw, level + 1);
            appendPrefix(buf, prefixChars).append("</").append(currentNode.getNodeName()).append(">\n");
          }
          tw.setCurrentNode(currentNode);
          break;
        case Node.TEXT_NODE:
          String val = currentNode.getNodeValue().trim();
          if (val.length() > 0)
            buf.append(StringUtil.escapeXMLText(val));
          break;
        case Node.COMMENT_NODE:
          appendPrefix(buf, prefixChars).append("<!--").append(currentNode.getNodeValue()).append("-->");
          break;
        case Node.PROCESSING_INSTRUCTION_NODE:
          appendPrefix(buf, prefixChars).append("<?").append(currentNode.getNodeName()).append(' ').append(currentNode.getNodeValue()).append("?>");
          break;
        case Node.CDATA_SECTION_NODE:
          appendPrefix(buf, prefixChars).append("<![CDATA[").append(currentNode.getNodeValue()).append("]]>");
          break;
        case Node.DOCUMENT_TYPE_NODE:
          DocumentType dt = (DocumentType) currentNode;
          buf.append("<!DOCTYPE ").append(currentNode.getNodeName());
          if (dt.getPublicId() != null) {
            buf.append(" PUBLIC \"").append(dt.getPublicId()).append("\"");
            buf.append(" \"").append(dt.getSystemId()).append("\"");
          } else if (dt.getSystemId() != null) {
            buf.append(" SYSTEM \"").append(dt.getSystemId()).append("\"");
          }
          if (dt.getInternalSubset() != null) {
            buf.append(" [\n");
            buf.append(dt.getInternalSubset());
            buf.append("]");
          }
          buf.append(">");
          break;
      }

      currentNode = tw.nextSibling();
    }
  }

  private String getAttributeValue(Node attr) {
    return StringUtil.escapeQuoteCharacter(StringUtil.escapeXMLText(attr.getNodeValue()));
  }

  private StringBuffer appendNewLine(StringBuffer buf) {
    if (!endsWithNewLine(buf))
      buf.append('\n');
    return buf;
  }

  private boolean endsWithNewLine(StringBuffer buf) {
    return buf.charAt(buf.length() - 1) == '\n';
  }

  private StringBuffer appendPrefix(StringBuffer buf, char[] prefix) {
    if (endsWithNewLine(buf))
      buf.append(prefix);
    return buf;
  }
}