+/*
+ * 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.rewrite;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+import org.apache.log4j.Logger;
+import org.apache.log4j.spi.LoggingEvent;
+
+/**
+ * This policy rewrites events where the message of the
+ * original event implementes java.util.Map.
+ * All other events are passed through unmodified.
+ * If the map contains a "message" entry, the value will be
+ * used as the message for the rewritten event. The rewritten
+ * event will have a property set that is the combination of the
+ * original property set and the other members of the message map.
+ * If both the original property set and the message map
+ * contain the same entry, the value from the message map
+ * will overwrite the original property set.
+ *
+ * The combination of the RewriteAppender and this policy
+ * performs the same actions as the MapFilter from log4j 1.3.
+ */
+public class MapRewritePolicy implements RewritePolicy {
+ /**
+ * {@inheritDoc}
+ */
+ public LoggingEvent rewrite(final LoggingEvent source) {
+ Object msg = source.getMessage();
+ if (msg instanceof Map) {
+ Map props = new HashMap(source.getProperties());
+ Map eventProps = (Map) msg;
+ //
+ // if the map sent in the logging request
+ // has "message" entry, use that as the message body
+ // otherwise, use the entire map.
+ //
+ Object newMsg = eventProps.get("message");
+ if (newMsg == null) {
+ newMsg = msg;
+ }
+
+ for(Iterator iter = eventProps.entrySet().iterator();
+ iter.hasNext();
+ ) {
+ Map.Entry entry = (Map.Entry) iter.next();
+ if (!("message".equals(entry.getKey()))) {
+ props.put(entry.getKey(), entry.getValue());
+ }
+ }
+
+ return new LoggingEvent(
+ source.getFQNOfLoggerClass(),
+ source.getLogger() != null ? source.getLogger(): Logger.getLogger(source.getLoggerName()),
+ source.getTimeStamp(),
+ source.getLevel(),
+ newMsg,
+ source.getThreadName(),
+ source.getThrowableInformation(),
+ source.getNDC(),
+ source.getLocationInformation(),
+ props);
+ } else {
+ return source;
+ }
+
+ }
+}