text: /*
   * Copyright 2013 the original author or authors.
   *
   * Licensed 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.springframework.xd.dirt.plugins.stream;
  
  import static org.springframework.xd.module.ModuleType.processor;
  import static org.springframework.xd.module.ModuleType.sink;
  import static org.springframework.xd.module.ModuleType.source;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.springframework.core.convert.support.GenericConversionService;
  import org.springframework.util.MimeType;
  import org.springframework.xd.module.ModuleDefinition;
  import org.springframework.xd.module.ModuleType;
  import org.springframework.xd.module.options.FlattenedCompositeModuleOptionsMetadata;
  import org.springframework.xd.module.options.ModuleOptionsMetadata;
  import org.springframework.xd.module.options.ModuleOptionsMetadataResolver;
  import org.springframework.xd.module.options.PojoModuleOptionsMetadata;
  import org.springframework.xd.module.options.spi.ModuleOption;
  
  /**
   * A {@link ModuleOptionsMetadataResolver} that will dynamically add {@code inputType} and {@code outputType} options to
   * every module, according to their type.
   * 
   * @see ModuleTypeConversionPlugin
   * @author Eric Bottard
   * @author David Turanski
   */
  public class ModuleTypeConversionPluginMetadataResolver implements ModuleOptionsMetadataResolver {
  
  	private final GenericConversionService conversionService = new GenericConversionService();
  
  	public ModuleTypeConversionPluginMetadataResolver() {
  		conversionService.addConverter(new CustomMimeTypeConverter());
  	}
  
  
  	@Override
  	public ModuleOptionsMetadata resolve(ModuleDefinition moduleDefinition) {
  		List<ModuleOptionsMetadata> moms = new ArrayList<ModuleOptionsMetadata>();
  		ModuleType type = moduleDefinition.getType();
  		if (type == source || type == processor) {
  			moms.add(new PojoModuleOptionsMetadata(OutputOptionsMetadata.class, conversionService));
  		}
  		if (type == sink || type == processor) {
  			moms.add(new PojoModuleOptionsMetadata(InputOptionsMetadata.class, conversionService));
  		}
  
  		// Don't force deep layering if it's not needed
  		switch (moms.size()) {
  			case 0:
  				return null;
  			case 1:
  				return moms.iterator().next();
  			default:
  				return new FlattenedCompositeModuleOptionsMetadata(moms);
  		}
  	}
  
  	/**
  	 * Provides info about the {@code inputType} option.
  	 * 
  	 * @author Eric Bottard
  	 */
  	@SuppressWarnings("unused")
  	private static class InputOptionsMetadata {
  
  		private MimeType inputType;
  
  		public MimeType getInputType() {
  			return inputType;
  		}
  
  		@ModuleOption("how this module should interpret messages it consumes")
  		public void setInputType(MimeType inputType) {
  			this.inputType = inputType;
  		}
  	}
  
  	/**
  	 * Provides info about the {@code outputType} option.
  	 * 
  	 * @author Eric Bottard
  	 */
  	@SuppressWarnings("unused")
  	private static class OutputOptionsMetadata {
  
  		private MimeType outputType;
  
  		public MimeType getOutputType() {
  			return outputType;
  		}
  
  
  		@ModuleOption("how this module should emit messages it produces")
  		public void setOutputType(MimeType outputType) {
  			this.outputType = outputType;
  		}
  
  	}
  
  }
  