simplify interval string parsing

Author: cloud-fan

common/unsafe/src/main/java/org/apache/spark/unsafe/types/CalendarInterval.java

@@ -32,94 +32,11 @@ public final class CalendarInterval implements Serializable {
   public static final long MICROS_PER_DAY = MICROS_PER_HOUR * 24;
   public static final long MICROS_PER_WEEK = MICROS_PER_DAY * 7;
 
-  /**
-   * A function to generate regex which matches interval string's unit part like "3 years".
-   *
-   * First, we can leave out some units in interval string, and we only care about the value of
-   * unit, so here we use non-capturing group to wrap the actual regex.
-   * At the beginning of the actual regex, we should match spaces before the unit part.
-   * Next is the number part, starts with an optional "-" to represent negative value. We use
-   * capturing group to wrap this part as we need the value later.
-   * Finally is the unit name, ends with an optional "s".
-   */
-  private static String unitRegex(String unit) {
-    return "(?:\\s+(-?\\d+)\\s+" + unit + "s?)?";
-  }
-
-  private static Pattern p = Pattern.compile("interval" + unitRegex("year") + unitRegex("month") +
-    unitRegex("week") + unitRegex("day") + unitRegex("hour") + unitRegex("minute") +
-    unitRegex("second") + unitRegex("millisecond") + unitRegex("microsecond"),
-    Pattern.CASE_INSENSITIVE);
-
-  private static Pattern yearMonthPattern =
-    Pattern.compile("^(?:['|\"])?([+|-])?(\\d+)-(\\d+)(?:['|\"])?$");
+  private static Pattern yearMonthPattern = Pattern.compile(
+    "^([+|-])?(\\d+)-(\\d+)$");
 
   private static Pattern dayTimePattern = Pattern.compile(
-    "^(?:['|\"])?([+|-])?((\\d+) )?((\\d+):)?(\\d+):(\\d+)(\\.(\\d+))?(?:['|\"])?$");
-
-  private static Pattern quoteTrimPattern = Pattern.compile("^(?:['|\"])?(.*?)(?:['|\"])?$");
-
-  private static long toLong(String s) {
-    if (s == null) {
-      return 0;
-    } else {
-      return Long.parseLong(s);
-    }
-  }
-
-  /**
-   * Convert a string to CalendarInterval. Return null if the input string is not a valid interval.
-   * This method is case-insensitive.
-   */
-  public static CalendarInterval fromString(String s) {
-    try {
-      return fromCaseInsensitiveString(s);
-    } catch (IllegalArgumentException e) {
-      return null;
-    }
-  }
-
-  /**
-   * Convert a string to CalendarInterval. This method can handle
-   * strings without the `interval` prefix and throws IllegalArgumentException
-   * when the input string is not a valid interval.
-   *
-   * @throws IllegalArgumentException if the string is not a valid internal.
-   */
-  public static CalendarInterval fromCaseInsensitiveString(String s) {
-    if (s == null) {
-      throw new IllegalArgumentException("Interval cannot be null");
-    }
-    String trimmed = s.trim();
-    if (trimmed.isEmpty()) {
-      throw new IllegalArgumentException("Interval cannot be blank");
-    }
-    String prefix = "interval";
-    String intervalStr = trimmed;
-    // Checks the given interval string does not start with the `interval` prefix
-    if (!intervalStr.regionMatches(true, 0, prefix, 0, prefix.length())) {
-      // Prepend `interval` if it does not present because
-      // the regular expression strictly require it.
-      intervalStr = prefix + " " + trimmed;
-    } else if (intervalStr.length() == prefix.length()) {
-      throw new IllegalArgumentException("Interval string must have time units");
-    }
-
-    Matcher m = p.matcher(intervalStr);
-    if (!m.matches()) {
-      throw new IllegalArgumentException("Invalid interval: " + s);
-    }
-
-    long months = toLong(m.group(1)) * 12 + toLong(m.group(2));
-    long microseconds = toLong(m.group(3)) * MICROS_PER_WEEK;
-    microseconds += toLong(m.group(4)) * MICROS_PER_DAY;
-    microseconds += toLong(m.group(5)) * MICROS_PER_HOUR;
-    microseconds += toLong(m.group(6)) * MICROS_PER_MINUTE;
-    microseconds += toLong(m.group(7)) * MICROS_PER_SECOND;
-    microseconds += toLong(m.group(8)) * MICROS_PER_MILLI;
-    microseconds += toLong(m.group(9));
-    return new CalendarInterval((int) months, microseconds);
-  }
+    "^([+|-])?((\\d+) )?((\\d+):)?(\\d+):(\\d+)(\\.(\\d+))?$");
 
   public static long toLongWithRange(String fieldName,
       String s, long minValue, long maxValue) throws IllegalArgumentException {
@@ -250,62 +167,55 @@ public static CalendarInterval fromSingleUnitString(String unit, String s)
       throw new IllegalArgumentException(String.format("Interval %s string was null", unit));
     }
     s = s.trim();
-    Matcher m = quoteTrimPattern.matcher(s);
-    if (!m.matches()) {
-      throw new IllegalArgumentException(
-        "Interval string does not match day-time format of 'd h:m:s.n': " + s);
-    } else {
-      try {
-        switch (unit) {
-          case "year":
-            int year = (int) toLongWithRange("year", m.group(1),
-              Integer.MIN_VALUE / 12, Integer.MAX_VALUE / 12);
-            result = new CalendarInterval(year * 12, 0L);
-            break;
-          case "month":
-            int month = (int) toLongWithRange("month", m.group(1),
-              Integer.MIN_VALUE, Integer.MAX_VALUE);
-            result = new CalendarInterval(month, 0L);
-            break;
-          case "week":
-            long week = toLongWithRange("week", m.group(1),
-              Long.MIN_VALUE / MICROS_PER_WEEK, Long.MAX_VALUE / MICROS_PER_WEEK);
-            result = new CalendarInterval(0, week * MICROS_PER_WEEK);
-            break;
-          case "day":
-            long day = toLongWithRange("day", m.group(1),
-              Long.MIN_VALUE / MICROS_PER_DAY, Long.MAX_VALUE / MICROS_PER_DAY);
-            result = new CalendarInterval(0, day * MICROS_PER_DAY);
-            break;
-          case "hour":
-            long hour = toLongWithRange("hour", m.group(1),
-              Long.MIN_VALUE / MICROS_PER_HOUR, Long.MAX_VALUE / MICROS_PER_HOUR);
-            result = new CalendarInterval(0, hour * MICROS_PER_HOUR);
-            break;
-          case "minute":
-            long minute = toLongWithRange("minute", m.group(1),
-              Long.MIN_VALUE / MICROS_PER_MINUTE, Long.MAX_VALUE / MICROS_PER_MINUTE);
-            result = new CalendarInterval(0, minute * MICROS_PER_MINUTE);
-            break;
-          case "second": {
-            long micros = parseSecondNano(m.group(1));
-            result = new CalendarInterval(0, micros);
-            break;
-          }
-          case "millisecond":
-            long millisecond = toLongWithRange("millisecond", m.group(1),
-              Long.MIN_VALUE / MICROS_PER_MILLI, Long.MAX_VALUE / MICROS_PER_MILLI);
-            result = new CalendarInterval(0, millisecond * MICROS_PER_MILLI);
-            break;
-          case "microsecond": {
-            long micros = Long.parseLong(m.group(1));
-            result = new CalendarInterval(0, micros);
-            break;
-          }
+    try {
+      switch (unit) {
+        case "year":
+          int year = (int) toLongWithRange("year", s,
+            Integer.MIN_VALUE / 12, Integer.MAX_VALUE / 12);
+          result = new CalendarInterval(year * 12, 0L);
+          break;
+        case "month":
+          int month = (int) toLongWithRange("month", s,
+            Integer.MIN_VALUE, Integer.MAX_VALUE);
+          result = new CalendarInterval(month, 0L);
+          break;
+        case "week":
+          long week = toLongWithRange("week", s,
+            Long.MIN_VALUE / MICROS_PER_WEEK, Long.MAX_VALUE / MICROS_PER_WEEK);
+          result = new CalendarInterval(0, week * MICROS_PER_WEEK);
+          break;
+        case "day":
+          long day = toLongWithRange("day", s,
+            Long.MIN_VALUE / MICROS_PER_DAY, Long.MAX_VALUE / MICROS_PER_DAY);
+          result = new CalendarInterval(0, day * MICROS_PER_DAY);
+          break;
+        case "hour":
+          long hour = toLongWithRange("hour", s,
+            Long.MIN_VALUE / MICROS_PER_HOUR, Long.MAX_VALUE / MICROS_PER_HOUR);
+          result = new CalendarInterval(0, hour * MICROS_PER_HOUR);
+          break;
+        case "minute":
+          long minute = toLongWithRange("minute", s,
+            Long.MIN_VALUE / MICROS_PER_MINUTE, Long.MAX_VALUE / MICROS_PER_MINUTE);
+          result = new CalendarInterval(0, minute * MICROS_PER_MINUTE);
+          break;
+        case "second": {
+          long micros = parseSecondNano(s);
+          result = new CalendarInterval(0, micros);
+          break;
         }
-      } catch (Exception e) {
-        throw new IllegalArgumentException("Error parsing interval string: " + e.getMessage(), e);
+        case "millisecond":
+          long millisecond = toLongWithRange("millisecond", s,
+            Long.MIN_VALUE / MICROS_PER_MILLI, Long.MAX_VALUE / MICROS_PER_MILLI);
+          result = new CalendarInterval(0, millisecond * MICROS_PER_MILLI);
+          break;
+        case "microsecond":
+          long micros = Long.parseLong(s);
+          result = new CalendarInterval(0, micros);
+          break;
       }
+    } catch (Exception e) {
+      throw new IllegalArgumentException("Error parsing interval string: " + e.getMessage(), e);
     }
     return result;
   }