Currently if we create a record it's fields are compared in their declaration
order. This might be ineffective in cases when two objects have "heavy" fields
equals to each other, but different "lightweight" fields (heavy and lightweight
in terms of comparison) e.g. primitives, enums, nullable/non-nulls etc.
If we have declared a record like
public record MyRecord(String field1, int field2) {}
It's equals() looks like:
public final equals(Ljava/lang/Object;)Z
L0
LINENUMBER 3 L0
ALOAD 0
ALOAD 1
INVOKEDYNAMIC
equals(Lcom/caspianone/openbanking/productservice/controller/MyRecord;Ljava/lang/Object;)Z
[
// handle kind 0x6 : INVOKESTATIC
java/lang/runtime/ObjectMethods.bootstrap(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/TypeDescriptor;Ljava/lang/Class;Ljava/lang/String;[Ljava/lang/invoke/MethodHandle;)Ljava/lang/Object;
// arguments:
com.caspianone.openbanking.productservice.controller.MyRecord.class,
"field1;field2",
// handle kind 0x1 : GETFIELD
com/caspianone/openbanking/productservice/controller/MyRecord.field1(Ljava/lang/String;),
// handle kind 0x1 : GETFIELD
com/caspianone/openbanking/productservice/controller/MyRecord.field2(I)
]
IRETURN
L1
LOCALVARIABLE this
Lcom/caspianone/openbanking/productservice/controller/MyRecord; L0 L1 0
LOCALVARIABLE o Ljava/lang/Object; L0 L1 1
MAXSTACK = 2
MAXLOCALS = 2
This can be improved by rearranging the comparison order of the fields moving
enums and primitives upper, and collections/arrays lower.
-------------
Commit messages:
- 8322292: Update copyright
- 8322292: Shift arrays and Iterables down
- Improve Record.equals()
Changes: https://git.openjdk.org/jdk/pull/17143/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17143&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8322292
Stats: 12 lines in 1 file changed: 9 ins; 0 del; 3 mod
Patch: https://git.openjdk.org/jdk/pull/17143.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/17143/head:pull/17143
PR: https://git.openjdk.org/jdk/pull/17143
