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[jOOQ/jOOQ#11099] Some performance improvements in Convert

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- Shortcut in Convert::convert if the value is already of the right type, prevents the ConvertAll allocations, and a few branches
- Shortcut in Convert::convert0 if the Converter.fromType() is Object.class, then we don't need an additional ConvertAll<>(fromType) round trip, which is a no-op
- In ConvertAll, delay the calls to wrapper(Class) until they're needed
- In ConvertAll, shortcuts should be ordered as:
  - null check
  - class equality check
  - class assignability check
  - wrapper type equality check
This commit is contained in:
Lukas Eder 2020-12-10 14:08:50 +01:00
parent 78e211fee3
commit 091322bd4d
1 changed files with 22 additions and 20 deletions
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42
jOOQ/src/main/java/org/jooq/tools/Convert.java
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@ -387,9 +387,14 @@ public final class Convert {
/**
* Conversion type-safety
*/
@SuppressWarnings("unchecked")
private static final <T, U> U convert0(Object from, Converter<T, ? extends U> converter) throws DataTypeException {
ConvertAll<T> all = new ConvertAll<>(converter.fromType());
return converter.from(all.from(from));
Class<T> fromType = converter.fromType();
if (fromType == Object.class)
return converter.from((T) from);
else
return converter.from(new ConvertAll<>(fromType).from(from));
}
/**
@ -455,7 +460,10 @@ public final class Convert {
* @throws DataTypeException - When the conversion is not possible
*/
public static final <T> T convert(Object from, Class<? extends T> toClass) throws DataTypeException {
return convert(from, new ConvertAll<T>(toClass));
if (from != null && from.getClass() == toClass)
return (T) from;
else
return convert(from, new ConvertAll<T>(toClass));
}
/**
@ -539,35 +547,30 @@ public final class Convert {
}
else if (toClass == Optional.class) {
else if (toClass == Optional.class)
return (U) Optional.empty();
}
else {
else
return null;
}
}
else {
final Class<?> fromClass = from.getClass();
final Class<?> wrapperTo = wrapper(toClass);
final Class<?> wrapperFrom = wrapper(fromClass);
final Class<?> wrapperTo;
final Class<?> wrapperFrom;
// No conversion
if (toClass == fromClass) {
if (toClass == fromClass)
return (U) from;
}
// [#6790] No conversion for primitive / wrapper conversions
else if (wrapperTo == wrapperFrom) {
return (U) from;
}
// [#2535] Simple up-casting can be done early
// [#1155] ... up-casting includes (toClass == Object.class)
else if (toClass.isAssignableFrom(fromClass)) {
else if (toClass.isAssignableFrom(fromClass))
return (U) from;
// [#6790] No conversion for primitive / wrapper conversions
else if ((wrapperTo = wrapper(toClass)) == (wrapperFrom = wrapper(fromClass)))
return (U) from;
}
// Regular checks
else if (fromClass == byte[].class) {
@ -615,9 +618,8 @@ public final class Convert {
}
else if (toClass == Optional.class) {
else if (toClass == Optional.class)
return (U) Optional.of(from);
}
// All types can be converted into String