I extend a new node to process chinese texts and want to disguise it as the word parser node so that I can use the other nodes in the Text Processing Plugin. But I found I couldn't use the object like DocumentCell, Document in the org.knime.ext.textprocessing.data package. So how can I do to extend a new node and want to use some object in the ext packages.
it should be possible to use classes defined in other extension if you define an appropriate plugin dependency. In your case you should add something like org.knime.ext.textprocessing (or whatever the plugin ID of the text processing plugin is) to the "Require-Bundle" section in the manifest.mf of your plugin. Sometimes I had also to add the jar files explicitely to the project classpath for building (the manifest controls only the runtime).
Hope that helps,