+/*
+ * 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.helpers;
+
+import org.apache.log4j.spi.LoggingEvent;
+
+/**
+
+ <p>PatternConverter is an abtract class that provides the
+ formatting functionality that derived classes need.
+
+ <p>Conversion specifiers in a conversion patterns are parsed to
+ individual PatternConverters. Each of which is responsible for
+ converting a logging event in a converter specific manner.
+
+ @author <a href="mailto:cakalijp@Maritz.com">James P. Cakalic</a>
+ @author Ceki Gülcü
+
+ @since 0.8.2
+ */
+public abstract class PatternConverter {
+ public PatternConverter next;
+ int min = -1;
+ int max = 0x7FFFFFFF;
+ boolean leftAlign = false;
+
+ protected
+ PatternConverter() { }
+
+ protected
+ PatternConverter(FormattingInfo fi) {
+ min = fi.min;
+ max = fi.max;
+ leftAlign = fi.leftAlign;
+ }
+
+ /**
+ Derived pattern converters must override this method in order to
+ convert conversion specifiers in the correct way.
+ */
+ abstract
+ protected
+ String convert(LoggingEvent event);
+
+ /**
+ A template method for formatting in a converter specific way.
+ */
+ public
+ void format(StringBuffer sbuf, LoggingEvent e) {
+ String s = convert(e);
+
+ if(s == null) {
+ if(0 < min) {
+ spacePad(sbuf, min);
+ }
+ return;
+ }
+
+ int len = s.length();
+
+ if(len > max) {
+ sbuf.append(s.substring(len-max));
+ } else if(len < min) {
+ if(leftAlign) {
+ sbuf.append(s);
+ spacePad(sbuf, min-len);
+ }
+ else {
+ spacePad(sbuf, min-len);
+ sbuf.append(s);
+ }
+ } else {
+ sbuf.append(s);
+ }
+ }
+
+ static String[] SPACES = {" ", " ", " ", " ", //1,2,4,8 spaces
+ " ", // 16 spaces
+ " " }; // 32 spaces
+
+ /**
+ Fast space padding method.
+ */
+ public
+ void spacePad(StringBuffer sbuf, int length) {
+ while(length >= 32) {
+ sbuf.append(SPACES[5]);
+ length -= 32;
+ }
+
+ for(int i = 4; i >= 0; i--) {
+ if((length & (1<<i)) != 0) {
+ sbuf.append(SPACES[i]);
+ }
+ }
+ }
+}