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package com.sun.beans.finder;

import com.sun.beans.util.Cache;

import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;

import static com.sun.beans.util.Cache.Kind.SOFT;
import static sun.reflect.misc.ReflectUtil.isPackageAccessible;

This utility class provides static methods to find a public constructor with specified parameter types in specified class.
Author:Sergey A. Malenkov
Since:1.7
/** * This utility class provides {@code static} methods * to find a public constructor with specified parameter types * in specified class. * * @since 1.7 * * @author Sergey A. Malenkov */
public final class ConstructorFinder extends AbstractFinder<Constructor<?>> { private static final Cache<Signature, Constructor<?>> CACHE = new Cache<Signature, Constructor<?>>(SOFT, SOFT) { @Override public Constructor create(Signature signature) { try { ConstructorFinder finder = new ConstructorFinder(signature.getArgs()); return finder.find(signature.getType().getConstructors()); } catch (Exception exception) { throw new SignatureException(exception); } } };
Finds public constructor that is declared in public class.
Params:
  • type – the class that can have constructor
  • args – parameter types that is used to find constructor
Throws:
Returns:object that represents found constructor
/** * Finds public constructor * that is declared in public class. * * @param type the class that can have constructor * @param args parameter types that is used to find constructor * @return object that represents found constructor * @throws NoSuchMethodException if constructor could not be found * or some constructors are found */
public static Constructor<?> findConstructor(Class<?> type, Class<?>...args) throws NoSuchMethodException { if (type.isPrimitive()) { throw new NoSuchMethodException("Primitive wrapper does not contain constructors"); } if (type.isInterface()) { throw new NoSuchMethodException("Interface does not contain constructors"); } if (Modifier.isAbstract(type.getModifiers())) { throw new NoSuchMethodException("Abstract class cannot be instantiated"); } if (!Modifier.isPublic(type.getModifiers()) || !isPackageAccessible(type)) { throw new NoSuchMethodException("Class is not accessible"); } PrimitiveWrapperMap.replacePrimitivesWithWrappers(args); Signature signature = new Signature(type, args); try { return CACHE.get(signature); } catch (SignatureException exception) { throw exception.toNoSuchMethodException("Constructor is not found"); } }
Creates constructor finder with specified array of parameter types.
Params:
  • args – the array of parameter types
/** * Creates constructor finder with specified array of parameter types. * * @param args the array of parameter types */
private ConstructorFinder(Class<?>[] args) { super(args); }
Returns an array of Class objects that represent the formal parameter types of the constructor. Returns an empty array if the constructor takes no parameters.
Params:
  • constructor – the object that represents constructor
Returns:the parameter types of the constructor
/** * Returns an array of {@code Class} objects * that represent the formal parameter types of the constructor. * Returns an empty array if the constructor takes no parameters. * * @param constructor the object that represents constructor * @return the parameter types of the constructor */
@Override protected Class<?>[] getParameters(Constructor<?> constructor) { return constructor.getParameterTypes(); }
Returns true if and only if the constructor was declared to take a variable number of arguments.
Params:
  • constructor – the object that represents constructor
Returns:true if the constructor was declared to take a variable number of arguments; false otherwise
/** * Returns {@code true} if and only if the constructor * was declared to take a variable number of arguments. * * @param constructor the object that represents constructor * @return {@code true} if the constructor was declared * to take a variable number of arguments; * {@code false} otherwise */
@Override protected boolean isVarArgs(Constructor<?> constructor) { return constructor.isVarArgs(); } }