Package com.norconex.importer.handler.transformer.impl

Class DOMDeleteTransformer

  • All Implemented Interfaces:
    IXMLConfigurable, IImporterHandler, IDocumentTransformer
    public class DOMDeleteTransformer
extends AbstractDocumentTransformer

    Enables deletion of one or more elements matching a given selector from a document content. Applies to HTML, XHTML, or XML document. To deal with DOM elements in metadata fields, use DOMTagger instead.

    This class constructs a DOM tree from the document content. That DOM tree is loaded entirely into memory. Use this transformer with caution if you know you'll need to parse huge files. It may be preferable to use ReplaceTransformer if this is a concern. Also, to help performance and avoid re-creating DOM tree before every DOM operations you want to perform, try to combine multiple extractions in a single instance of this transformer.

    The jsoup parser library is used to load a document content into a DOM tree. Elements are referenced using a CSS or JQuery-like syntax.

    Should be used as a pre-parse handler.

    Content-types

    By default, this filter is restricted to (applies only to) documents matching the restrictions returned by CommonRestrictions.domContentTypes(String). You can specify your own content types if you know they represent a file with HTML or XML-like markup tags.

    When used as a pre-parse handler, this class attempts to detect the content character encoding unless the character encoding was specified using setSourceCharset(String).

    You can specify which parser to use when reading documents. The default is "html" and will normalize the content as HTML. This is generally a desired behavior, but this can sometimes have your selector fail. If you encounter this problem, try switching to "xml" parser, which does not attempt normalization on the content. The drawback with "xml" is you may not get all HTML-specific selector options to work. If you know you are dealing with XML to begin with, specifying "xml" should be a good option.

    XML configuration usage:

    
<handler
    class="com.norconex.importer.handler.transformer.impl.DOMDeleteTransformer"
    parser="[html|xml]"
    sourceCharset="(character encoding)">
  <!-- multiple "restrictTo" tags allowed (only one needs to match) -->
  <restrictTo>
    <fieldMatcher>(field-matching expression)</fieldMatcher>
    <valueMatcher>(value-matching expression)</valueMatcher>
  </restrictTo>
  <!-- multiple "dom" tags allowed -->
  <dom
      selector="(selector syntax)"/>
</handler>

    XML usage example:

    
<handler
    class="DOMDeleteTransformer">
  <dom
      selector="div.firstName"/>
</handler>

    Given this HTML snippet... 

     <div class="firstName">Joe</div>
 <div class="lastName">Dalton</div>

    ... the above example will delete "Joe" but keep "Dalton".

    Since:
    3.0.0
    Author:
    Pascal Essiembre
    See Also:
    DOMTagger, DOMPreserveTransformer