JAVA-2507: When available (starting with Java 8), use java.time.format.DateFormatter.ISO_OFFSET_DATE_TIME instead of javax.xml.bind.DatatypeConverter.parseDateTime

Author: jyemin

bson/src/main/org/bson/json/DateTimeFormatter.java

@@ -0,0 +1,125 @@
+/*
+ * Copyright 2017 MongoDB, Inc.
+ *
+ * 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 org.bson.json;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.time.Instant;
+import java.time.format.DateTimeParseException;
+import java.time.temporal.TemporalAccessor;
+import java.time.temporal.TemporalQuery;
+import java.util.Calendar;
+
+import static java.time.format.DateTimeFormatter.ISO_OFFSET_DATE_TIME;
+
+final class DateTimeFormatter {
+    private static final FormatterImpl FORMATTER_IMPL;
+
+    static {
+        FormatterImpl dateTimeHelper;
+        try {
+            dateTimeHelper = loadDateTimeFormatter("org.bson.json.DateTimeFormatter$Java8DateTimeFormatter");
+        } catch (LinkageError e) {
+            // this is expected if running on a release prior to Java 8: fallback to JAXB.
+            dateTimeHelper = loadDateTimeFormatter("org.bson.json.DateTimeFormatter$JaxbDateTimeFormatter");
+        }
+
+        FORMATTER_IMPL = dateTimeHelper;
+    }
+
+    private static FormatterImpl loadDateTimeFormatter(final String className) {
+        try {
+            return (FormatterImpl) Class.forName(className).newInstance();
+        } catch (ClassNotFoundException e) {
+            // this is unexpected as it means the class itself is not found
+            throw new ExceptionInInitializerError(e);
+        } catch (InstantiationException e) {
+            // this is unexpected as it means the class can't be instantiated
+            throw new ExceptionInInitializerError(e);
+        } catch (IllegalAccessException e) {
+            // this is unexpected as it means the no-args constructor isn't accessible
+            throw new ExceptionInInitializerError(e);
+        }
+    }
+
+    static long parse(final String dateTimeString) {
+        return FORMATTER_IMPL.parse(dateTimeString);
+    }
+
+    private interface FormatterImpl {
+        long parse(String dateTimeString);
+    }
+
+    // Reflective use of DatatypeConverter avoids a compile-time dependency on the java.xml.bind module in Java 9
+    static class JaxbDateTimeFormatter implements FormatterImpl {
+
+        private static final Method DATATYPE_CONVERTER_PARSE_DATE_TIME_METHOD;
+
+        static {
+            try {
+                DATATYPE_CONVERTER_PARSE_DATE_TIME_METHOD = Class.forName("javax.xml.bind.DatatypeConverter")
+                                                                    .getDeclaredMethod("parseDateTime", String.class);
+            } catch (NoSuchMethodException e) {
+                throw new ExceptionInInitializerError(e);
+            } catch (ClassNotFoundException e) {
+                throw new ExceptionInInitializerError(e);
+            }
+        }
+
+        @Override
+        public long parse(final String dateTimeString) {
+            try {
+                return ((Calendar) DATATYPE_CONVERTER_PARSE_DATE_TIME_METHOD.invoke(null, dateTimeString)).getTimeInMillis();
+            } catch (IllegalAccessException e) {
+                throw new IllegalStateException(e);
+            } catch (InvocationTargetException e) {
+                throw (RuntimeException) e.getCause();
+            }
+        }
+    }
+
+    static class Java8DateTimeFormatter implements FormatterImpl {
+
+        // if running on Java 8 or above then java.time.format.DateTimeFormatter will be available and initialization will succeed.
+        // Otherwise it will fail.
+        static {
+            try {
+                Class.forName("java.time.format.DateTimeFormatter");
+            } catch (ClassNotFoundException e) {
+                throw new ExceptionInInitializerError(e);
+            }
+        }
+
+        @Override
+        public long parse(final String dateTimeString) {
+            try {
+                return ISO_OFFSET_DATE_TIME.parse(dateTimeString, new TemporalQuery<Instant>() {
+                    @Override
+                    public Instant queryFrom(final TemporalAccessor temporal) {
+                        return Instant.from(temporal);
+                    }
+                }).toEpochMilli();
+            } catch (DateTimeParseException e) {
+                throw new IllegalArgumentException(e.getMessage());
+            }
+        }
+    }
+
+    private DateTimeFormatter() {
+    }
+}

bson/src/main/org/bson/json/JsonReader.java

@@ -36,7 +36,6 @@
 import org.bson.types.MinKey;
 import org.bson.types.ObjectId;
 
-import javax.xml.bind.DatatypeConverter;
 import java.text.DateFormat;
 import java.text.ParsePosition;
 import java.text.SimpleDateFormat;
@@ -989,7 +988,7 @@ private long visitDateTimeExtendedJson() {
             } else if (valueToken.getType() == JsonTokenType.STRING) {
                 String dateTimeString = valueToken.getValue(String.class);
                 try {
-                    value = DatatypeConverter.parseDateTime(dateTimeString).getTimeInMillis();
+                    value = DateTimeFormatter.parse(dateTimeString);
                 } catch (IllegalArgumentException e) {
                     throw new JsonParseException("Failed to parse string as a date", e);
                 }