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Optimize equals for faster short-circuiting #1136

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Merged
adwsingh merged 1 commit into from
Apr 3, 2026
Merged

Optimize equals for faster short-circuiting #1136

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51 changes: 50 additions & 1 deletion ...core/src/main/java/software/amazon/smithy/java/codegen/generators/StructureGenerator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
import java.util.Arrays;
import java.util.Base64;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Objects;
Expand Down Expand Up @@ -401,7 +402,8 @@ private void writeMemberEquals(JavaWriter writer) {
}

private void writePropertyEqualityChecks(JavaWriter writer) {
var iter = shape.members().iterator();
var iter =
shape.members().stream().sorted(new CheapEqualsFirstComparator(symbolProvider, model)).iterator();
while (iter.hasNext()) {
var member = iter.next();
var memberSymbol = symbolProvider.toSymbol(member);
Expand All @@ -428,6 +430,53 @@ private void writePropertyEqualityChecks(JavaWriter writer) {
writer.popState();
}
}

private record CheapEqualsFirstComparator(SymbolProvider symbolProvider, Model model)
implements Comparator<MemberShape> {

// Equality cost ranking by shape type (lower = cheaper).
// Primitives using == are cheapest, followed by types using static compare methods,
// then Object.equals/Arrays.equals comparisons.
private static final List<ShapeType> COST_RANKING = List.of(
ShapeType.BOOLEAN,
ShapeType.BYTE,
ShapeType.SHORT,
ShapeType.INTEGER,
ShapeType.INT_ENUM,
ShapeType.LONG,
ShapeType.FLOAT,
ShapeType.DOUBLE,
ShapeType.STRING,
ShapeType.ENUM,
ShapeType.TIMESTAMP,
ShapeType.BIG_INTEGER,
ShapeType.BIG_DECIMAL,
ShapeType.BLOB,
ShapeType.UNION,
ShapeType.STRUCTURE,
ShapeType.LIST,
ShapeType.MAP,
ShapeType.DOCUMENT);

@Override
public int compare(MemberShape o1, MemberShape o2) {
return Integer.compare(costOf(o1), costOf(o2));
}

private int costOf(MemberShape member) {
var symbol = symbolProvider.toSymbol(member);
boolean isPrimitive = symbol.getProperty(SymbolProperties.IS_PRIMITIVE).orElse(false)
&& !CodegenUtils.isNullableMember(model, member);
var targetType = model.expectShape(member.getTarget()).getType();
int typeRank = COST_RANKING.indexOf(targetType);
if (typeRank < 0) {
typeRank = COST_RANKING.size();
}
// Boxed members use Objects.equals, which is more expensive than any primitive op.
// Shift them after all primitive types in the ranking.
return isPrimitive ? typeRank : COST_RANKING.size() + typeRank;
}
}
}

private record HashCodeGenerator(JavaWriter writer, Shape shape, SymbolProvider symbolProvider, Model model)
Expand Down
28 changes: 14 additions & 14 deletions ...tware/amazon/smithy/java/codegen/types/test-cases/defaults/expected/DefaultStructure.java
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Original file line number Diff line number Diff line change
Expand Up @@ -237,31 +237,31 @@ public boolean equals(Object other) {
}
DefaultStructure that = (DefaultStructure) other;
return this.booleanMember == that.booleanMember
&& Objects.equals(this.bigDecimal, that.bigDecimal)
&& Objects.equals(this.bigDecimalWithDoubleDefault, that.bigDecimalWithDoubleDefault)
&& Objects.equals(this.bigDecimalWithLongDefault, that.bigDecimalWithLongDefault)
&& Objects.equals(this.bigInteger, that.bigInteger)
&& Objects.equals(this.bigIntegerWithLongDefault, that.bigIntegerWithLongDefault)
&& this.byteMember == that.byteMember
&& Double.compare(this.doubleMember, that.doubleMember) == 0
&& Float.compare(this.floatMember, that.floatMember) == 0
&& this.shortMember == that.shortMember
&& this.integer == that.integer
&& this.longMember == that.longMember
&& this.shortMember == that.shortMember
&& Float.compare(this.floatMember, that.floatMember) == 0
&& Double.compare(this.doubleMember, that.doubleMember) == 0
&& Objects.equals(this.intEnum, that.intEnum)
&& Objects.equals(this.string, that.string)
&& Objects.equals(this.enumMember, that.enumMember)
&& Objects.equals(this.timestamp, that.timestamp)
&& Objects.equals(this.bigInteger, that.bigInteger)
&& Objects.equals(this.bigIntegerWithLongDefault, that.bigIntegerWithLongDefault)
&& Objects.equals(this.bigDecimal, that.bigDecimal)
&& Objects.equals(this.bigDecimalWithDoubleDefault, that.bigDecimalWithDoubleDefault)
&& Objects.equals(this.bigDecimalWithLongDefault, that.bigDecimalWithLongDefault)
&& Objects.equals(this.blob, that.blob)
&& Objects.equals(this.streamingBlob, that.streamingBlob)
&& Objects.equals(this.list, that.list)
&& Objects.equals(this.map, that.map)
&& Objects.equals(this.boolDoc, that.boolDoc)
&& Objects.equals(this.stringDoc, that.stringDoc)
&& Objects.equals(this.numberDoc, that.numberDoc)
&& Objects.equals(this.floatingPointnumberDoc, that.floatingPointnumberDoc)
&& Objects.equals(this.listDoc, that.listDoc)
&& Objects.equals(this.mapDoc, that.mapDoc)
&& Objects.equals(this.list, that.list)
&& Objects.equals(this.map, that.map)
&& Objects.equals(this.timestamp, that.timestamp)
&& Objects.equals(this.enumMember, that.enumMember)
&& Objects.equals(this.intEnum, that.intEnum);
&& Objects.equals(this.mapDoc, that.mapDoc);
}

@Override
Expand Down
8 changes: 4 additions & 4 deletions ...tware/amazon/smithy/java/codegen/types/test-cases/jspecify/expected/CollectionStruct.java
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Original file line number Diff line number Diff line change
Expand Up @@ -172,12 +172,12 @@ public boolean equals(Object other) {
CollectionStruct that = (CollectionStruct) other;
return Objects.equals(this.nonSparseList, that.nonSparseList)
&& Objects.equals(this.sparseList, that.sparseList)
&& Objects.equals(this.nonSparseMap, that.nonSparseMap)
&& Objects.equals(this.sparseMap, that.sparseMap)
&& Objects.equals(this.nonSparseListOfSparseMap, that.nonSparseListOfSparseMap)
&& Objects.equals(this.sparseListOfSparseMap, that.sparseListOfSparseMap)
&& Objects.equals(this.sparseMapOfNonSparseList, that.sparseMapOfNonSparseList)
&& Objects.equals(this.nonSparseListOfNonSparseMap, that.nonSparseListOfNonSparseMap);
&& Objects.equals(this.nonSparseListOfNonSparseMap, that.nonSparseListOfNonSparseMap)
&& Objects.equals(this.nonSparseMap, that.nonSparseMap)
&& Objects.equals(this.sparseMap, that.sparseMap)
&& Objects.equals(this.sparseMapOfNonSparseList, that.sparseMapOfNonSparseList);
}

@Override
Expand Down
4 changes: 2 additions & 2 deletions ...oftware/amazon/smithy/java/codegen/types/test-cases/jspecify/expected/JSpecifyStruct.java
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Original file line number Diff line number Diff line change
Expand Up @@ -80,9 +80,9 @@ public boolean equals(Object other) {
return false;
}
JSpecifyStruct that = (JSpecifyStruct) other;
return Objects.equals(this.requiredString, that.requiredString)
return this.requiredPrimitive == that.requiredPrimitive
&& Objects.equals(this.requiredString, that.requiredString)
&& Objects.equals(this.optionalString, that.optionalString)
&& this.requiredPrimitive == that.requiredPrimitive
&& Objects.equals(this.sparseList, that.sparseList);
}

Expand Down
2 changes: 1 addition & 1 deletion ...re/amazon/smithy/java/codegen/types/test-cases/naming-conflict/expected/NamingStruct.java
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Original file line number Diff line number Diff line change
Expand Up @@ -115,10 +115,10 @@ public boolean equals(Object other) {
}
NamingStruct that = (NamingStruct) other;
return Objects.equals(this.other, that.other)
&& Objects.equals(this.union, that.union)
&& Objects.equals(this.builderMember, that.builderMember)
&& Objects.equals(this.type, that.type)
&& Objects.equals(this.objectMember, that.objectMember)
&& Objects.equals(this.union, that.union)
&& Objects.equals(this.map, that.map)
&& Objects.equals(this.list, that.list)
&& Objects.equals(this.listOfList, that.listOfList)
Expand Down
6 changes: 3 additions & 3 deletions .../smithy/java/codegen/types/test-cases/primitive-types/expected/PrimitivesNotNullable.java
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Expand Up @@ -88,13 +88,13 @@ public boolean equals(Object other) {
return false;
}
PrimitivesNotNullable that = (PrimitivesNotNullable) other;
return this.byteMember == that.byteMember
return this.booleanMember == that.booleanMember
&& this.byteMember == that.byteMember
&& this.shortMember == that.shortMember
&& this.intMember == that.intMember
&& this.longMember == that.longMember
&& Float.compare(this.floatMember, that.floatMember) == 0
&& Double.compare(this.doubleMember, that.doubleMember) == 0
&& this.booleanMember == that.booleanMember;
&& Double.compare(this.doubleMember, that.doubleMember) == 0;
}

@Override
Expand Down
6 changes: 3 additions & 3 deletions ...zon/smithy/java/codegen/types/test-cases/primitive-types/expected/PrimitivesNullable.java
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Original file line number Diff line number Diff line change
Expand Up @@ -88,13 +88,13 @@ public boolean equals(Object other) {
return false;
}
PrimitivesNullable that = (PrimitivesNullable) other;
return Objects.equals(this.byteMember, that.byteMember)
return Objects.equals(this.booleanMember, that.booleanMember)
&& Objects.equals(this.byteMember, that.byteMember)
&& Objects.equals(this.shortMember, that.shortMember)
&& Objects.equals(this.intMember, that.intMember)
&& Objects.equals(this.longMember, that.longMember)
&& Objects.equals(this.floatMember, that.floatMember)
&& Objects.equals(this.doubleMember, that.doubleMember)
&& Objects.equals(this.booleanMember, that.booleanMember);
&& Objects.equals(this.doubleMember, that.doubleMember);
}

@Override
Expand Down
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