add: - 'DateFormatThreadLocal': a 'ThreadLocal' extension initialized with a 'SimpleDateFormat'.

SVN: 6295

common/source/java/ch/systemsx/cisd/common/utilities/DateFormatThreadLocal.java

+/*
+ * Copyright 2008 ETH Zuerich, CISD
+ *
+ * Licensed 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 ch.systemsx.cisd.common.utilities;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+
+/**
+ * A small <code>ThreadLocal</code> extension suitable for non-threadsafe {@link DateFormat}.
+ * <p>
+ * As <i>Javadoc</i> states, {@link DateFormat}s are inherently unsafe for multithreaded use.
+ * </p>
+ * 
+ * @author Christian Ribeaud
+ */
+public final class DateFormatThreadLocal extends ThreadLocal<SimpleDateFormat>
+{
+
+    private final String pattern;
+
+    public DateFormatThreadLocal(final String pattern)
+    {
+        this.pattern = pattern;
+    }
+
+    //
+    // ThreadLocal
+    //
+
+    @Override
+    protected final SimpleDateFormat initialValue()
+    {
+        return new SimpleDateFormat(pattern);
+    }
+}
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