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java/org/apache/catalina/util/ConcurrentDateFormat.java

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+/*
+ * 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.catalina.util;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.Queue;
+import java.util.TimeZone;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+/**
+ * A thread safe wrapper around {@link SimpleDateFormat} that does not make use
+ * of ThreadLocal and - broadly - only creates enough SimpleDateFormat objects
+ * to satisfy the concurrency requirements.
+ *
+ * @deprecated Unused. This will be removed in Tomcat 10.
+ *             Use {@link org.apache.tomcat.util.http.ConcurrentDateFormat}
+ */
+@Deprecated
+public class ConcurrentDateFormat {
+
+    private final String format;
+    private final Locale locale;
+    private final TimeZone timezone;
+    private final Queue<SimpleDateFormat> queue = new ConcurrentLinkedQueue<>();
+
+    public static final String RFC1123_DATE = "EEE, dd MMM yyyy HH:mm:ss zzz";
+    public static final TimeZone GMT = TimeZone.getTimeZone("GMT");
+
+    private static final ConcurrentDateFormat FORMAT_RFC1123;
+
+    static {
+        FORMAT_RFC1123 = new ConcurrentDateFormat(RFC1123_DATE, Locale.US, GMT);
+    }
+
+    public static String formatRfc1123(Date date) {
+        return FORMAT_RFC1123.format(date);
+    }
+
+    public ConcurrentDateFormat(String format, Locale locale,
+            TimeZone timezone) {
+        this.format = format;
+        this.locale = locale;
+        this.timezone = timezone;
+        SimpleDateFormat initial = createInstance();
+        queue.add(initial);
+    }
+
+    public String format(Date date) {
+        SimpleDateFormat sdf = queue.poll();
+        if (sdf == null) {
+            sdf = createInstance();
+        }
+        String result = sdf.format(date);
+        queue.add(sdf);
+        return result;
+    }
+
+    private SimpleDateFormat createInstance() {
+        SimpleDateFormat sdf = new SimpleDateFormat(format, locale);
+        sdf.setTimeZone(timezone);
+        return sdf;
+    }
+}