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/*
* Copyright (c) 2010, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.glassfish.jersey.internal.util;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
/**
* Type visitor contract.
*
* @param type visiting result type.
* @author Kohsuke Kawaguchi
* @author Marek Potociar (marek.potociar at oracle.com)
*/
abstract class TypeVisitor {
/**
* Visit the type and a given parameter.
*
* @param type visited type.
* @return visiting result.
*/
public final T visit(final Type type) {
assert type != null;
if (type instanceof Class) {
return onClass((Class) type);
}
if (type instanceof ParameterizedType) {
return onParameterizedType((ParameterizedType) type);
}
if (type instanceof GenericArrayType) {
return onGenericArray((GenericArrayType) type);
}
if (type instanceof WildcardType) {
return onWildcard((WildcardType) type);
}
if (type instanceof TypeVariable) {
return onVariable((TypeVariable) type);
}
// covered all the cases
assert false;
throw createError(type);
}
/**
* Visit class.
*
* @param clazz visited class.
* @return visit result.
*/
protected abstract T onClass(Class clazz);
/**
* Visit parameterized type.
*
* @param type visited parameterized type.
* @return visit result.
*/
protected abstract T onParameterizedType(ParameterizedType type);
/**
* Visit generic array type.
*
* @param type visited parameterized type.
* @return visit result.
*/
protected abstract T onGenericArray(GenericArrayType type);
/**
* Visit type variable.
*
* @param type visited parameterized type.
* @return visit result.
*/
protected abstract T onVariable(TypeVariable type);
/**
* Visit wildcard type.
*
* @param type visited parameterized type.
* @return visit result.
*/
protected abstract T onWildcard(WildcardType type);
/**
* Create visiting error (in case the visitor could not recognize the visit type.
*
* @param type visited parameterized type.
* @return visit result.
*/
protected RuntimeException createError(final Type type) {
throw new IllegalArgumentException();
}
}