A content transformer is used to transform content from one format to another. Content transformers are implemented as a Java class configured as a Spring bean. Alfresco finds the appropriate transformer based on source and target MIME type. There are two important use cases for transformers. The first is when an end user triggers a transformation, usually through an action. The most well-known out of the box example is converting Microsoft Office documents to PDF. Other out of the box transformers include:
HTML-to-text
Microsoft Excel-to-CSV
Microsoft Word-to-text
PDF-to-text
Images-to-Images
See the Appendix for further details on the out of the box transformers.
The second key transformer use case involves the Solr full-text search engine. Solr indexes content when it is added to the repository. But the Alfresco Tracker code embedded in Solr only understands plain text. The Solr process sends queries every 15 seconds by default to Alfresco to get...