Implementation:Risingwavelabs Risingwave DynConstructors

Property	Value
File	java/connector-node/risingwave-sink-iceberg/src/main/java/org/apache/iceberg/common/DynConstructors.java
Language	Java
Lines	298
Category	Utility
Package	org.apache.iceberg.common
Origin	Ported from Apache Parquet / Apache Iceberg project

Overview

DynConstructors is a utility class providing a builder pattern for dynamically locating and invoking Java constructors via reflection. Originally copied from parquet-common and ported into the Apache Iceberg project, it enables dynamic instantiation of classes without compile-time constructor dependencies. The class provides a Builder for searching constructors across multiple classes and a Ctor wrapper that extends DynMethods.UnboundMethod for unified invocation semantics.

Code Reference

Source Location

java/connector-node/risingwave-sink-iceberg/src/main/java/org/apache/iceberg/common/DynConstructors.java

Signature

public class DynConstructors {
    private DynConstructors() {}
    public static Builder builder();
    public static Builder builder(Class<?> baseClass);

    public static class Ctor<C> extends DynMethods.UnboundMethod {
        public Class<? extends C> getConstructedClass();
        public C newInstanceChecked(Object... args) throws Exception;
        public C newInstance(Object... args);
        public <R> R invoke(Object target, Object... args);
        public <R> R invokeChecked(Object target, Object... args) throws Exception;
    }

    public static class Builder {
        public Builder loader(ClassLoader newLoader);
        public Builder impl(String className, Class<?>... types);
        public <T> Builder impl(Class<T> targetClass, Class<?>... types);
        public Builder hiddenImpl(Class<?>... types);
        public Builder hiddenImpl(String className, Class<?>... types);
        public <T> Builder hiddenImpl(Class<T> targetClass, Class<?>... types);
        public <C> Ctor<C> buildChecked() throws NoSuchMethodException;
        public <C> Ctor<C> build();
    }
}

Imports

import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
import org.apache.iceberg.relocated.com.google.common.base.Throwables;
import org.apache.iceberg.relocated.com.google.common.collect.Maps;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.Map;

I/O Contract

Ctor (Inner Class)

The Ctor<C> class wraps a Java Constructor<C> and provides:

Method	Description
getConstructedClass()	Returns the Class that this constructor creates
newInstanceChecked(Object... args)	Creates a new instance; if more args are provided than the constructor accepts, truncates to match parameter count. Propagates checked exceptions.
newInstance(Object... args)	Creates a new instance; wraps checked exceptions as RuntimeException
invoke(Object target, Object... args)	Delegates to newInstance(); target must be null (enforced by precondition)
invokeChecked(Object target, Object... args)	Delegates to newInstanceChecked(); target must be null
bind(Object receiver)	Always throws IllegalStateException (constructors cannot be bound)
isStatic()	Always returns true

Builder Methods

Method	Description
loader(ClassLoader)	Sets the ClassLoader for class lookup (currently a no-op in this implementation)
impl(String className, Class<?>... types)	Tries to find a public constructor on the named class matching the given parameter types
impl(Class<T> targetClass, Class<?>... types)	Tries to find a public constructor on the given class matching the parameter types
hiddenImpl(Class<?>... types)	Tries to find a hidden (non-public) constructor on the base class
hiddenImpl(String className, Class<?>... types)	Tries to find a hidden constructor on the named class matching the parameter types
hiddenImpl(Class<T> targetClass, Class<?>... types)	Tries to find a hidden constructor on the given class; uses AccessController.doPrivileged() to make it accessible
buildChecked()	Returns the found Ctor; throws NoSuchMethodException with detailed problem descriptions if none found
build()	Returns the found Ctor; throws RuntimeException with detailed problem descriptions if none found

Error Reporting

The builder maintains a Map<String, Throwable> of problems encountered during constructor searches. When build() or buildChecked() fails, the error message includes all attempted methods and their failure reasons, with each original exception added as a suppressed exception.

Usage Examples

// Find a public constructor by class name and parameter types
DynConstructors.Ctor<MyCatalog> ctor = DynConstructors.builder()
    .impl("org.apache.iceberg.aws.glue.GlueCatalog")
    .impl("org.apache.iceberg.hive.HiveCatalog")
    .buildChecked();
MyCatalog catalog = ctor.newInstance();

// Find a hidden constructor with specific parameter types
DynConstructors.Ctor<MyClass> ctor = DynConstructors.builder(MyClass.class)
    .hiddenImpl(MyClass.class, String.class, int.class)
    .build();
MyClass instance = ctor.newInstance("arg1", 42);

// Using with a base class constraint
DynConstructors.Ctor<Catalog> ctor = DynConstructors.builder(Catalog.class)
    .impl("com.example.CustomCatalog", Map.class)
    .build();
Catalog catalog = ctor.newInstance(configMap);

Related Pages

• DynClasses - Companion utility for dynamically loading classes by name
• JniCatalogWrapper LoadTable - Iceberg catalog operations that may use dynamic constructor invocation