| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.knox.gateway.filter.rewrite.impl; |
| |
| import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteStepDescriptor; |
| import org.apache.knox.gateway.filter.rewrite.spi.UrlRewriteStepProcessor; |
| |
| import java.lang.reflect.ParameterizedType; |
| import java.lang.reflect.Type; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.ServiceLoader; |
| |
| public abstract class UrlRewriteStepProcessorFactory { |
| |
| private static final Map<Class<? extends UrlRewriteStepDescriptor>,Map<String,Class<? extends UrlRewriteStepProcessor>>> MAP |
| = loadStepProcessors(); |
| |
| private UrlRewriteStepProcessorFactory() { |
| } |
| |
| public static UrlRewriteStepProcessor create( UrlRewriteStepDescriptor descriptor ) throws IllegalAccessException, InstantiationException { |
| UrlRewriteStepProcessor processor; |
| Map<String,Class<? extends UrlRewriteStepProcessor>> typeMap; |
| typeMap = MAP.get( descriptor.getClass() ); |
| if( typeMap == null ) { |
| Class<? extends UrlRewriteStepDescriptor> descriptorInterface = getDescriptorInterface( descriptor ); |
| typeMap = MAP.get( descriptorInterface ); |
| } |
| if( typeMap == null ) { |
| throw new IllegalArgumentException( descriptor.getClass().getName() ); |
| } else { |
| String type = descriptor.type(); |
| Class<? extends UrlRewriteStepProcessor> processorClass = typeMap.get( type ); |
| if( processorClass == null ) { |
| throw new IllegalArgumentException( type ); |
| } else { |
| processor = processorClass.newInstance(); |
| } |
| } |
| return processor; |
| } |
| |
| private static Map<Class<? extends UrlRewriteStepDescriptor>,Map<String,Class<? extends UrlRewriteStepProcessor>>> loadStepProcessors() { |
| Map<Class<? extends UrlRewriteStepDescriptor>,Map<String,Class<? extends UrlRewriteStepProcessor>>> descriptorMap |
| = new HashMap<>(); |
| ServiceLoader<UrlRewriteStepProcessor> processors = ServiceLoader.load( UrlRewriteStepProcessor.class ); |
| for( UrlRewriteStepProcessor processor : processors ) { |
| Class<? extends UrlRewriteStepDescriptor> descriptorInterface = getDescriptorInterface( processor ); |
| Map<String, Class<? extends UrlRewriteStepProcessor>> typeMap = descriptorMap |
| .computeIfAbsent(descriptorInterface, k -> new HashMap<>()); |
| String processorType = processor.getType(); |
| typeMap.put( processorType, processor.getClass() ); |
| } |
| return descriptorMap; |
| } |
| |
| private static Class<? extends UrlRewriteStepDescriptor> getDescriptorInterface( UrlRewriteStepDescriptor descriptor ) { |
| Class<? extends UrlRewriteStepDescriptor> descriptorClass = null; |
| for( Type interfaceType : descriptor.getClass().getGenericInterfaces() ) { |
| Class genericClass = (Class)interfaceType; |
| if( UrlRewriteStepDescriptor.class.isAssignableFrom( genericClass ) ) { |
| descriptorClass = uncheckedStepDescriptorClassCast( genericClass ); |
| break; |
| } |
| } |
| return descriptorClass; |
| } |
| |
| private static Class<? extends UrlRewriteStepDescriptor> getDescriptorInterface( UrlRewriteStepProcessor processor ) { |
| Class<? extends UrlRewriteStepDescriptor> descriptorClass = null; |
| Class<? extends UrlRewriteStepProcessor> processorClass = processor.getClass(); |
| for( Type interfaceType : processorClass.getGenericInterfaces() ) { |
| if( UrlRewriteStepProcessor.class.isAssignableFrom( (Class)((ParameterizedType)interfaceType).getRawType() ) ) { |
| ParameterizedType interfaceClass = (ParameterizedType)interfaceType; |
| descriptorClass = uncheckedStepDescriptorClassCast( interfaceClass.getActualTypeArguments()[ 0 ] ); |
| break; |
| } |
| } |
| return descriptorClass; |
| } |
| |
| @SuppressWarnings("unchecked") |
| private static Class<? extends UrlRewriteStepDescriptor> uncheckedStepDescriptorClassCast( Type type ) { |
| return (Class<? extends UrlRewriteStepDescriptor>)type; |
| } |
| |
| } |