Make SimpleDateFormat usages thread-local to fix date parsing corruption

CHANGELOG.md

@@ -2,6 +2,7 @@
 _Generated automatically by maven_
 
 ## Next Release
+ *  *2020-08-27 14:37:38*  [#228](https://github.com/rcongiu/Hive-JSON-Serde/pull/228) Make usages of SimpleDateFormat thread-local and therefore thread safe _[@pettyjamesm](https://github.com/pettjamesm)_
  *  *2017-10-06 10:04:22*  Add configuration for explicit null value in the serialized output JSON  _(lyair1)_
 
 ## 1.3.8

json-serde-cdh5-shim/src/main/java/org/openx/data/jsonserde/objectinspector/primitive/JavaStringDateObjectInspector.java

@@ -5,15 +5,14 @@
 import org.apache.hadoop.hive.serde2.objectinspector.primitive.SettableDateObjectInspector;
 
 import java.sql.Date;
-import java.text.SimpleDateFormat;
 
 /**
  * Created by rcongiu on 11/12/15.
  */
 public class JavaStringDateObjectInspector  extends AbstractPrimitiveJavaObjectInspector
         implements SettableDateObjectInspector {
 
-    private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
+    private static final ThreadLocalSimpleDateFormat sdf = new ThreadLocalSimpleDateFormat("yyyy-MM-dd");
 
     public JavaStringDateObjectInspector() {
         super(TypeEntryShim.dateType);

json-serde/src/main/java/org/openx/data/jsonserde/objectinspector/primitive/ParsePrimitiveUtils.java

@@ -6,10 +6,7 @@
 package org.openx.data.jsonserde.objectinspector.primitive;
 
 import java.sql.Timestamp;
-import java.text.DateFormat;
 import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Calendar;
 import java.util.Date;
 import java.util.TimeZone;
 import java.util.regex.Pattern;
@@ -25,16 +22,9 @@ private ParsePrimitiveUtils() {
     }
 
     // timestamps are expected to be in UTC
-    public final static DateFormat UTC_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
-    public final static DateFormat OFFSET_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX");
-    public final static DateFormat NON_UTC_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-    static DateFormat[] dateFormats = { UTC_FORMAT, OFFSET_FORMAT,NON_UTC_FORMAT};
-    static {
-        TimeZone tz = TimeZone.getTimeZone("UTC");
-        for( DateFormat df : dateFormats) {
-            df.setTimeZone(tz);
-        }
-    }
+    public final static ThreadLocalSimpleDateFormat UTC_FORMAT = new ThreadLocalSimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", TimeZone.getTimeZone("UTC"));
+    public final static ThreadLocalSimpleDateFormat OFFSET_FORMAT = new ThreadLocalSimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX", TimeZone.getTimeZone("UTC"));
+    public final static ThreadLocalSimpleDateFormat NON_UTC_FORMAT = new ThreadLocalSimpleDateFormat("yyyy-MM-dd HH:mm:ss", TimeZone.getTimeZone("UTC"));
 
     static Pattern hasTZOffset = Pattern.compile(".+(\\+|-)\\d{2}:?\\d{2}$");
 

json/src/main/java/org/openx/data/jsonserde/objectinspector/primitive/ThreadLocalSimpleDateFormat.java

@@ -0,0 +1,52 @@
+package org.openx.data.jsonserde.objectinspector.primitive;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.TimeZone;
+
+/**
+ * Wraps a {@link SimpleDateFormat} instance with a {@link ThreadLocal} since the former is not thread safe and
+ * mutates more than a few underlying fields directly during parsing. When used from multiple fields, this can
+ * corrupt data in a way that may or may not cause exceptions (ie: can cause silent corruption).
+ */
+final class ThreadLocalSimpleDateFormat {
+    private final ThreadLocal<SimpleDateFormat> threadLocal;
+
+    public ThreadLocalSimpleDateFormat(final String pattern) {
+        this(pattern, null);
+    }
+
+    public ThreadLocalSimpleDateFormat(final String pattern, final TimeZone timeZone) {
+        try {
+            SimpleDateFormat format = new SimpleDateFormat(pattern);
+            if (timeZone != null) {
+                format.setTimeZone(timeZone);
+            }
+        } catch (Exception e) {
+            throw new IllegalArgumentException("Failed to create ThreadLocalSimpleDateFormat with pattern: " + pattern, e);
+        }
+        this.threadLocal = new ThreadLocal<SimpleDateFormat>() {
+            @Override
+            public SimpleDateFormat initialValue() {
+                SimpleDateFormat format = new SimpleDateFormat(pattern);
+                if (timeZone != null) {
+                    format.setTimeZone(timeZone);
+                }
+                return format;
+            }
+        };
+    }
+
+    public Date parse(String source) throws ParseException {
+        return threadLocal.get().parse(source);
+    }
+
+    public String format(Date date) {
+        return threadLocal.get().format(date);
+    }
+
+    public String format(long value) {
+        return threadLocal.get().format(value);
+    }
+}