--- /dev/null
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.log4j.pattern;
+
+import org.apache.log4j.spi.LoggingEvent;
+
+
+/**
+ * LoggingEventPatternConverter is a base class for pattern converters
+ * that can format information from instances of LoggingEvent.
+ *
+ * @author Curt Arnold
+ *
+ */
+public abstract class LoggingEventPatternConverter extends PatternConverter {
+ /**
+ * Constructs an instance of LoggingEventPatternConverter.
+ * @param name name of converter.
+ * @param style CSS style for output.
+ */
+ protected LoggingEventPatternConverter(
+ final String name, final String style) {
+ super(name, style);
+ }
+
+ /**
+ * Formats an event into a string buffer.
+ * @param event event to format, may not be null.
+ * @param toAppendTo string buffer to which the formatted event will be appended. May not be null.
+ */
+ public abstract void format(
+ final LoggingEvent event, final StringBuffer toAppendTo);
+
+ /**
+ * {@inheritDoc}
+ */
+ public void format(final Object obj, final StringBuffer output) {
+ if (obj instanceof LoggingEvent) {
+ format((LoggingEvent) obj, output);
+ }
+ }
+
+ /**
+ * Normally pattern converters are not meant to handle Exceptions although
+ * few pattern converters might.
+ *
+ * By examining the return values for this method, the containing layout will
+ * determine whether it handles throwables or not.
+
+ * @return true if this PatternConverter handles throwables
+ */
+ public boolean handlesThrowable() {
+ return false;
+ }
+}