validating the date format, add test case, since NumberFormatExceptio… (

#2538)

* validating the date format, add test case, since NumberFormatException extends IllegalArgumentException, it is only necessary to write IllegalArgumentException.

* Apply code formatting with Spotless

---------

Co-authored-by: Carpe-Wang <wangcarpe@126.com>

gson/src/main/java/com/google/gson/GsonBuilder.java

@@ -43,6 +43,7 @@
 import com.google.gson.stream.JsonWriter;
 import java.lang.reflect.Type;
 import java.text.DateFormat;
+import java.text.SimpleDateFormat;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -598,7 +599,14 @@ public GsonBuilder disableHtmlEscaping() {
  */
  @CanIgnoreReturnValue
  public GsonBuilder setDateFormat(String pattern) {
- // TODO(Joel): Make this fail fast if it is an invalid date format
+ if (pattern != null) {
+ try {
+ new SimpleDateFormat(pattern);
+ } catch (IllegalArgumentException e) {
+ // Throw exception if it is an invalid date format
+ throw new IllegalArgumentException("The date pattern '" + pattern + "' is not valid", e);
+ }
+ }
  this.datePattern = pattern;
  return this;
  }

gson/src/main/java/com/google/gson/internal/bind/util/ISO8601Utils.java

@@ -289,11 +289,7 @@ public static Date parse(String date, ParsePosition pos) throws ParseException {
  return calendar.getTime();
  // If we get a ParseException it'll already have the right message/offset.
  // Other exception types can convert here.
- } catch (IndexOutOfBoundsException e) {
- fail = e;
- } catch (NumberFormatException e) {
- fail = e;
- } catch (IllegalArgumentException e) {
+ } catch (IndexOutOfBoundsException | IllegalArgumentException e) {
  fail = e;
  }
  String input = (date == null) ? null : ('"' + date + '"');

gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java

@@ -16,6 +16,7 @@
 package com.google.gson.functional;
 
 import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.fail;
 
 import com.google.gson.Gson;
@@ -737,6 +738,24 @@ public void testStringBufferDeserialization() {
  assertThat(sb.toString()).isEqualTo("abc");
  }
 
+ @Test
+ public void testSetDateFormatWithInvalidPattern() {
+ GsonBuilder builder = new GsonBuilder();
+ String invalidPattern = "This is a invalid Pattern";
+ assertThrows(
+ IllegalArgumentException.class,
+ () -> {
+ builder.setDateFormat(invalidPattern);
+ });
+ }
+
+ @Test
+ public void testSetDateFormatWithValidPattern() {
+ GsonBuilder builder = new GsonBuilder();
+ String validPattern = "yyyy-MM-dd";
+ builder.setDateFormat(validPattern);
+ }
+
  private static class MyClassTypeAdapter extends TypeAdapter<Class<?>> {
  @Override
  public void write(JsonWriter out, Class<?> value) throws IOException {