From 173e72429fb494ea3832e3e38ee90f165fbff4cf Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Sun, 7 Oct 2018 14:49:48 -0600
Subject: [PATCH 1/1] altoslib: NumberFormat can't be shared between parsers

AltosJson uses NumberFormat to ensure locale-independent parsing of
values. However, NumberFormat appears to have some internal state
which means that each thread needs to have an independent NumberFormat
object. Create one for each parser as needed.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 altoslib/AltosJson.java | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/altoslib/AltosJson.java b/altoslib/AltosJson.java
index 190d2633..b981c365 100644
--- a/altoslib/AltosJson.java
+++ b/altoslib/AltosJson.java
@@ -63,18 +63,22 @@ class JsonUtil {
 			result.append("\t");
 		return result;
 	}
-	static NumberFormat get_nf_json() {
-		DecimalFormat nf = (DecimalFormat) NumberFormat.getNumberInstance(Locale.ROOT);
-		nf.setParseIntegerOnly(false);
-		nf.setGroupingUsed(false);
-		nf.setMaximumFractionDigits(17);
-		nf.setMinimumFractionDigits(0);
-		nf.setMinimumIntegerDigits(1);
-		nf.setDecimalSeparatorAlwaysShown(false);
-		return nf;
-	}
-
-	static NumberFormat nf_json = get_nf_json();
+
+	NumberFormat _nf_json;
+
+	NumberFormat nf_json() {
+		if (_nf_json == null) {
+			DecimalFormat nf = (DecimalFormat) NumberFormat.getNumberInstance(Locale.ROOT);
+			nf.setParseIntegerOnly(false);
+			nf.setGroupingUsed(false);
+			nf.setMaximumFractionDigits(17);
+			nf.setMinimumFractionDigits(0);
+			nf.setMinimumIntegerDigits(1);
+			nf.setDecimalSeparatorAlwaysShown(false);
+			_nf_json = nf;
+		}
+		return _nf_json;
+	}
 }
 
 class JsonHash extends JsonUtil {
@@ -372,7 +376,7 @@ class JsonLexer extends JsonUtil {
 					String dstr = dbuf.toString();
 					double dval;
 					try {
-						dval = nf_json.parse(dstr).doubleValue();
+						dval = nf_json().parse(dstr).doubleValue();
 					} catch (ParseException pe) {
 						return new JsonToken(JsonToken._error, dstr);
 					}
@@ -612,7 +616,7 @@ public class AltosJson extends JsonUtil {
 			} else if (Double.isNaN(d_number)) {
 				result.append("NaN");
 			} else {
-				String dval = nf_json.format(d_number);
+				String dval = nf_json().format(d_number);
 				if (dval.equals("-0"))
 					dval = "0";
 				result.append(dval);
-- 
2.30.2