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ParameterList - Cache the size and avoid iterator pattern #1848

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Merged
merged 1 commit into from
Aug 15, 2025
+39 −12
Merged

ParameterList - Cache the size and avoid iterator pattern #1848

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51 changes: 39 additions & 12 deletions byte-buddy-dep/src/main/java/net/bytebuddy/description/method/ParameterList.java
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Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,11 @@ abstract class AbstractBase<S extends ParameterDescription> extends FilterableLi
* {@inheritDoc}
*/
public boolean hasExplicitMetaData() {
for (ParameterDescription parameterDescription : this) {
// cache the size and make sure to avoid iterators here
// this pattern reduces the number of allocations and also the CPU usage
int size = size();
for (int i = 0; i < size; i++) {
ParameterDescription parameterDescription = get(i);
if (!parameterDescription.isNamed() || !parameterDescription.hasModifiers()) {
return false;
}
Expand All @@ -91,9 +95,12 @@ public boolean hasExplicitMetaData() {
* {@inheritDoc}
*/
public ByteCodeElement.Token.TokenList<ParameterDescription.Token> asTokenList(ElementMatcher<? super TypeDescription> matcher) {
List<ParameterDescription.Token> tokens = new ArrayList<ParameterDescription.Token>(size());
for (ParameterDescription parameterDescription : this) {
tokens.add(parameterDescription.asToken(matcher));
// cache the size and make sure to avoid iterators here
// this pattern reduces the number of allocations and also the CPU usage
int size = size();
List<ParameterDescription.Token> tokens = new ArrayList<ParameterDescription.Token>(size);
for (int i = 0; i < size; i++) {
tokens.add(get(i).asToken(matcher));
}
return new ByteCodeElement.Token.TokenList<ParameterDescription.Token>(tokens);
}
Expand All @@ -102,9 +109,12 @@ public ByteCodeElement.Token.TokenList<ParameterDescription.Token> asTokenList(E
* {@inheritDoc}
*/
public TypeList.Generic asTypeList() {
List<TypeDescription.Generic> types = new ArrayList<TypeDescription.Generic>(size());
for (ParameterDescription parameterDescription : this) {
types.add(parameterDescription.getType());
// cache the size and make sure to avoid iterators here
// this pattern reduces the number of allocations and also the CPU usage
int size = size();
List<TypeDescription.Generic> types = new ArrayList<TypeDescription.Generic>(size);
for (int i = 0; i < size; i++) {
types.add(get(i).getType());
}
return new TypeList.Generic.Explicit(types);
}
Expand All @@ -113,9 +123,12 @@ public TypeList.Generic asTypeList() {
* {@inheritDoc}
*/
public ParameterList<ParameterDescription.InDefinedShape> asDefined() {
List<ParameterDescription.InDefinedShape> declaredForms = new ArrayList<ParameterDescription.InDefinedShape>(size());
for (ParameterDescription parameterDescription : this) {
declaredForms.add(parameterDescription.asDefined());
// cache the size and make sure to avoid iterators here
// this pattern reduces the number of allocations and also the CPU usage
int size = size();
List<ParameterDescription.InDefinedShape> declaredForms = new ArrayList<ParameterDescription.InDefinedShape>(size);
for (int i = 0; i < size; i++) {
declaredForms.add(get(i).asDefined());
}
return new Explicit<ParameterDescription.InDefinedShape>(declaredForms);
}
Expand Down Expand Up @@ -143,6 +156,13 @@ abstract class ForLoadedExecutable<T> extends AbstractBase<ParameterDescription.
*/
protected final T executable;

/**
* The number of parameters of this executable.
* <p>
* It is important to cache it as calling getParameterCount() via the dispatcher has a high cost.
*/
protected final int size;

/**
* The parameter annotation source to query.
*/
Expand All @@ -156,6 +176,7 @@ abstract class ForLoadedExecutable<T> extends AbstractBase<ParameterDescription.
*/
protected ForLoadedExecutable(T executable, ParameterDescription.ForLoadedParameter.ParameterAnnotationSource parameterAnnotationSource) {
this.executable = executable;
this.size = EXECUTABLE.getParameterCount(executable);
this.parameterAnnotationSource = parameterAnnotationSource;
}

Expand Down Expand Up @@ -223,7 +244,7 @@ public static ParameterList<ParameterDescription.InDefinedShape> of(Method metho
* {@inheritDoc}
*/
public int size() {
return EXECUTABLE.getParameterCount(executable);
return size;
}

/**
Expand Down Expand Up @@ -562,6 +583,11 @@ class TypeSubstituting extends AbstractBase<ParameterDescription.InGenericShape>
*/
private final List<? extends ParameterDescription> parameterDescriptions;

/**
* The number of parameters.
*/
private final int size;

/**
* The visitor to apply to the parameter types before returning them.
*/
Expand All @@ -579,6 +605,7 @@ public TypeSubstituting(MethodDescription.InGenericShape declaringMethod,
TypeDescription.Generic.Visitor<? extends TypeDescription.Generic> visitor) {
this.declaringMethod = declaringMethod;
this.parameterDescriptions = parameterDescriptions;
this.size = parameterDescriptions.size();
this.visitor = visitor;
}

Expand All @@ -593,7 +620,7 @@ public ParameterDescription.InGenericShape get(int index) {
* {@inheritDoc}
*/
public int size() {
return parameterDescriptions.size();
return size;
}
}

Expand Down