/**
* Logback: the reliable, generic, fast and flexible logging framework.
* Copyright (C) 1999-2015, QOS.ch. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation.
*/
package ch.qos.logback.core.pattern;
/**
* A minimal converter which sets up the general interface for derived classes.
* It also implements the functionality to chain converters in a linked list.
*
* @author ceki
*/
abstract public class Converter<E> {
Converter<E> next;
/**
* The convert method is responsible for extracting data from the event and
* storing it for later use by the write method.
*
* @param event
*/
public abstract String convert(E event);
/**
* In its simplest incarnation, a convert simply appends the data extracted from
* the event to the buffer passed as parameter.
*
* @param buf The input buffer where data is appended
* @param event The event from where data is extracted
*/
public void write(StringBuilder buf, E event) {
buf.append(convert(event));
}
public final void setNext(Converter<E> next) {
if (this.next != null) {
throw new IllegalStateException("Next converter has been already set");
}
this.next = next;
}
public final Converter<E> getNext() {
return next;
}
}