org.apache.xalan.trace

## Interface TraceListener

- All Superinterfaces:
    java.util.EventListener
  All Known Subinterfaces:
    TraceListenerEx, TraceListenerEx2, TraceListenerEx3
  All Known Implementing Classes:
    PrintTraceListener

      public interface TraceListener
      extends java.util.EventListener

  Interface the XSL processor calls when it matches a source node, selects a set of source nodes, or generates a result node. If you want an object instance to be called when a trace event occurs, use the TransformerImpl setTraceListener method.
  See Also:
    `TracerEvent`, `TraceManager.addTraceListener(org.apache.xalan.trace.TraceListener)`
  Usage:
    **For advanced use only**

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `generated(GenerateEvent ev)` Method that is called just after the formatter listener is called.
    `void` | `selected(SelectionEvent ev)` Method that is called just after the formatter listener is called.
    `void` | `trace(TracerEvent ev)` Method that is called when a trace event occurs.

- - ### Method Detail

    - #### trace

          void trace(TracerEvent ev)

      Method that is called when a trace event occurs. The method is blocking. It must return before processing continues.
      Parameters:
        `ev` - the trace event.

    - #### selected

          void selected(SelectionEvent ev)
                 throws javax.xml.transform.TransformerException

      Method that is called just after the formatter listener is called.
      Parameters:
        `ev` - the generate event.
      Throws:
        `javax.xml.transform.TransformerException`

    - #### generated

          void generated(GenerateEvent ev)

      Method that is called just after the formatter listener is called.
      Parameters:
        `ev` - the generate event.

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