From 1767fdf19ccf9dea510371641360e1ed65965db6 Mon Sep 17 00:00:00 2001
Date: Fri, 22 Jan 2021 15:16:23 +0800
Subject: backport of JDK-8031085

Summary: <class DateTimeFormatterBuilder.java>: DateTimeFormatter won't parse dates with custom format "yyyyMMddHHmmssSSS"
LLT: jdk/test/java/time/tck/java/time/format/TCKDateTimeFormatterBuilder.java
Bug url: https://bugs.openjdk.java.net/browse/JDK-8031085
---
 .../time/format/DateTimeFormatterBuilder.java | 79 ++++++++++++++++---
 .../format/TCKDateTimeFormatterBuilder.java   | 20 ++++-
 2 files changed, 86 insertions(+), 13 deletions(-)

diff --git a/jdk/src/share/classes/java/time/format/DateTimeFormatterBuilder.java b/jdk/src/share/classes/java/time/format/DateTimeFormatterBuilder.java
index 7e0698dfc..d57a16730 100644
--- a/jdk/src/share/classes/java/time/format/DateTimeFormatterBuilder.java
+++ b/jdk/src/share/classes/java/time/format/DateTimeFormatterBuilder.java
@@ -664,8 +664,11 @@ public final class DateTimeFormatterBuilder {
      * No rounding occurs due to the maximum width - digits are simply dropped.
      * <p>
      * When parsing in strict mode, the number of parsed digits must be between
-     * the minimum and maximum width. When parsing in lenient mode, the minimum
-     * width is considered to be zero and the maximum is nine.
+     * the minimum and maximum width. In strict mode, if the minimum and maximum widths
+     * are equal and there is no decimal point then the parser will
+     * participate in adjacent value parsing, see
+     * {@link appendValue(java.time.temporal.TemporalField, int)}. When parsing in lenient mode,
+     * the minimum width is considered to be zero and the maximum is nine.
      * <p>
      * If the value cannot be obtained then an exception will be thrown.
      * If the value is negative an exception will be thrown.
@@ -684,7 +687,12 @@ public final class DateTimeFormatterBuilder {
      */
     public DateTimeFormatterBuilder appendFraction(
             TemporalField field, int minWidth, int maxWidth, boolean decimalPoint) {
-        appendInternal(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
+        if (minWidth == maxWidth && decimalPoint == false) {
+            // adjacent parsing
+            appendValue(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
+        } else {
+            appendInternal(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
+        }
         return this;
     }
 
@@ -2907,10 +2915,7 @@ public final class DateTimeFormatterBuilder {
     /**
      * Prints and parses a numeric date-time field with optional padding.
      */
-    static final class FractionPrinterParser implements DateTimePrinterParser {
-        private final TemporalField field;
-        private final int minWidth;
-        private final int maxWidth;
+    static final class FractionPrinterParser extends NumberPrinterParser {
         private final boolean decimalPoint;
 
         /**
@@ -2922,6 +2927,7 @@ public final class DateTimeFormatterBuilder {
          * @param decimalPoint  whether to output the localized decimal point symbol
          */
         FractionPrinterParser(TemporalField field, int minWidth, int maxWidth, boolean decimalPoint) {
+            this(field, minWidth, maxWidth, decimalPoint, 0);
             Objects.requireNonNull(field, "field");
             if (field.range().isFixed() == false) {
                 throw new IllegalArgumentException("Field must have a fixed set of values: " + field);
@@ -2936,12 +2942,61 @@ public final class DateTimeFormatterBuilder {
                 throw new IllegalArgumentException("Maximum width must exceed or equal the minimum width but " +
                         maxWidth + " < " + minWidth);
             }
-            this.field = field;
-            this.minWidth = minWidth;
-            this.maxWidth = maxWidth;
+        }
+
+        /**
+         * Constructor.
+         *
+         * @param field  the field to output, not null
+         * @param minWidth  the minimum width to output, from 0 to 9
+         * @param maxWidth  the maximum width to output, from 0 to 9
+         * @param decimalPoint  whether to output the localized decimal point symbol
+         * @param subsequentWidth the subsequentWidth for this instance
+         */
+        FractionPrinterParser(TemporalField field, int minWidth, int maxWidth, boolean decimalPoint, int subsequentWidth) {
+            super(field, minWidth, maxWidth, SignStyle.NOT_NEGATIVE, subsequentWidth);
             this.decimalPoint = decimalPoint;
         }
 
+        /**
+         * Returns a new instance with fixed width flag set.
+         *
+         * @return a new updated printer-parser, not null
+         */
+        @Override
+        FractionPrinterParser withFixedWidth() {
+            if (subsequentWidth == -1) {
+                return this;
+            }
+            return new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint, -1);
+        }
+
+        /**
+         * Returns a new instance with an updated subsequent width.
+         *
+         * @param subsequentWidth  the width of subsequent non-negative numbers, 0 or greater
+         * @return a new updated printer-parser, not null
+         */
+        @Override
+        FractionPrinterParser withSubsequentWidth(int subsequentWidth) {
+            return new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint, this.subsequentWidth + subsequentWidth);
+        }
+
+        /**
+         * For FractionPrinterPrinterParser, the width is fixed if context is sttrict,
+         * minWidth equal to maxWidth and decimalpoint is absent.
+         * @param context the context
+         * @return if the field is fixed width
+         * @see DateTimeFormatterBuilder#appendValueFraction(java.time.temporal.TemporalField, int, int, boolean)
+         */
+        @Override
+        boolean isFixedWidth(DateTimeParseContext context) {
+            if (context.isStrict() && minWidth == maxWidth && decimalPoint == false) {
+                return true;
+            }
+            return false;
+        }
+
         @Override
         public boolean format(DateTimePrintContext context, StringBuilder buf) {
             Long value = context.getValue(field);
@@ -2974,8 +3029,8 @@ public final class DateTimeFormatterBuilder {
 
         @Override
         public int parse(DateTimeParseContext context, CharSequence text, int position) {
-            int effectiveMin = (context.isStrict() ? minWidth : 0);
-            int effectiveMax = (context.isStrict() ? maxWidth : 9);
+            int effectiveMin = (context.isStrict() || isFixedWidth(context) ? minWidth : 0);
+            int effectiveMax = (context.isStrict() || isFixedWidth(context) ? maxWidth : 9);
             int length = text.length();
             if (position == length) {
                 // valid if whole field is optional, invalid if minimum width
diff --git a/jdk/test/java/time/tck/java/time/format/TCKDateTimeFormatterBuilder.java b/jdk/test/java/time/tck/java/time/format/TCKDateTimeFormatterBuilder.java
index c5a017c91..f689cf651 100644
--- a/jdk/test/java/time/tck/java/time/format/TCKDateTimeFormatterBuilder.java
+++ b/jdk/test/java/time/tck/java/time/format/TCKDateTimeFormatterBuilder.java
@@ -69,6 +69,7 @@ import static org.testng.Assert.assertEquals;
 
 import java.text.ParsePosition;
 import java.time.LocalDate;
+import java.time.LocalDateTime;
 import java.time.YearMonth;
 import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
@@ -868,7 +869,7 @@ public class TCKDateTimeFormatterBuilder {
 
     @Test
     public void test_adjacent_lenient_fractionFollows_0digit() throws Exception {
-        // succeeds because hour/min are fixed width
+        // succeeds because hour, min and fraction of seconds are fixed width
         DateTimeFormatter f = builder.parseLenient().appendValue(HOUR_OF_DAY, 2).appendValue(MINUTE_OF_HOUR, 2).appendFraction(NANO_OF_SECOND, 3, 3, false).toFormatter(Locale.UK);
         ParsePosition pp = new ParsePosition(0);
         TemporalAccessor parsed = f.parseUnresolved("1230", pp);
@@ -878,4 +879,21 @@ public class TCKDateTimeFormatterBuilder {
         assertEquals(parsed.getLong(MINUTE_OF_HOUR), 30L);
     }
 
+    @DataProvider(name="adjacentFractionParseData")
+    Object[][] data_adjacent_fraction_parse() {
+        return new Object[][] {
+            {"20130812214600025", "yyyyMMddHHmmssSSS", LocalDateTime.of(2013, 8, 12, 21, 46, 00, 25000000)},
+            {"201308122146000256", "yyyyMMddHHmmssSSSS", LocalDateTime.of(2013, 8, 12, 21, 46, 00, 25600000)},
+        };
+    }
+
+    @Test(dataProvider = "adjacentFractionParseData")
+    public void test_adjacent_fraction(String input, String pattern, LocalDateTime expected) {
+        DateTimeFormatter dtf = DateTimeFormatter.ofPattern(pattern);
+        LocalDateTime actual = LocalDateTime.parse(input, dtf);
+        assertEquals(actual, expected);
+    }
+
+
+
 }
-- 
2.19.0