+/*
+ * 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;
+
+import java.util.Iterator;
+import java.util.Set;
+import org.apache.log4j.helpers.*;
+
+
+/**
+ * Able to handle the contents of the LoggingEvent's Property bundle and either
+ * output the entire contents of the properties in a similar format to the
+ * java.util.Hashtable.toString(), or to output the value of a specific key
+ * within the property bundle
+ * when this pattern converter has the option set.
+ *
+ * @author Paul Smith
+ * @author Ceki Gülcü
+ */
+public final class PropertiesPatternConverter
+ extends LoggingEventPatternConverter {
+ /**
+ * Name of property to output.
+ */
+ private final String option;
+
+ /**
+ * Private constructor.
+ * @param options options, may be null.
+ */
+ private PropertiesPatternConverter(
+ final String[] options) {
+ super(
+ ((options != null) && (options.length > 0))
+ ? ("Property{" + options[0] + "}") : "Properties", "property");
+
+ if ((options != null) && (options.length > 0)) {
+ option = options[0];
+ } else {
+ option = null;
+ }
+ }
+
+ /**
+ * Obtains an instance of PropertiesPatternConverter.
+ * @param options options, may be null or first element contains name of property to format.
+ * @return instance of PropertiesPatternConverter.
+ */
+ public static PropertiesPatternConverter newInstance(
+ final String[] options) {
+ return new PropertiesPatternConverter(options);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public void format(final LoggingEvent event, final StringBuffer toAppendTo) {
+ // if there is no additional options, we output every single
+ // Key/Value pair for the MDC in a similar format to Hashtable.toString()
+ if (option == null) {
+ toAppendTo.append("{");
+
+ try {
+ Set keySet = MDCKeySetExtractor.INSTANCE.getPropertyKeySet(event);
+ if (keySet != null) {
+ for (Iterator i = keySet.iterator(); i.hasNext();) {
+ Object item = i.next();
+ Object val = event.getMDC(item.toString());
+ toAppendTo.append("{").append(item).append(",").append(val).append(
+ "}");
+ }
+ }
+ } catch(Exception ex) {
+ LogLog.error("Unexpected exception while extracting MDC keys", ex);
+ }
+
+ toAppendTo.append("}");
+ } else {
+ // otherwise they just want a single key output
+ Object val = event.getMDC(option);
+
+ if (val != null) {
+ toAppendTo.append(val);
+ }
+ }
+ }
+}