content: /*
   * 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 com.alibaba.compileflow.engine.core.definition.extension;
  
  import org.apache.commons.collections4.CollectionUtils;
  import org.apache.commons.lang3.StringUtils;
  
  import java.util.ArrayList;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * @author wuxiang
   * @author yusu
   */
  public abstract class BaseExtensionElement {
  
      private Map<String, List<ExtensionElement>> extensionElements = new LinkedHashMap<>();
      private Map<String, List<ExtensionAttribute>> extensionAttributes = new LinkedHashMap<>();
  
      public void addExtensionElement(ExtensionElement extensionElement) {
          if (extensionElement != null && StringUtils.isNotEmpty(extensionElement.getName())) {
              List<ExtensionElement> extensionElements = this.extensionElements.computeIfAbsent(
                      extensionElement.getName(), name -> new ArrayList<>());
              extensionElements.add(extensionElement);
          }
      }
  
      public void addAttribute(ExtensionAttribute extensionAttribute) {
          if (extensionAttribute != null && StringUtils.isNotEmpty(extensionAttribute.getName())) {
              List<ExtensionAttribute> extensionAttributes = this.extensionAttributes.computeIfAbsent(
                      extensionAttribute.getName(), name -> new ArrayList<>());
              extensionAttributes.add(extensionAttribute);
          }
      }
  
      public List<ExtensionElement> getExtensionElements(String extensionElementName) {
          return extensionElements.get(extensionElementName);
      }
  
      public ExtensionElement getOnlyExtensionElement(String extensionElementName) {
          List<ExtensionElement> extensionElements = this.extensionElements.get(extensionElementName);
          if (extensionElements.size() == 1) {
              return extensionElements.get(0);
          } else {
              throw new IllegalStateException("Expected only one element of type " + extensionElementName);
          }
      }
  
      public String getAttributeValue(String name) {
          return getAttributeValue("", name);
      }
  
      public String getAttributeValueOrDefault(String name, String defaultValue) {
          String attributeValue = getAttributeValue("", name);
          if (StringUtils.isBlank(attributeValue)) {
              return defaultValue;
          }
          return attributeValue;
      }
  
      public String getAttributeValue(String namespace, String name) {
          List<ExtensionAttribute> attributes = extensionAttributes.get(name);
          if (CollectionUtils.isNotEmpty(attributes)) {
              return attributes.stream()
                      .filter(attribute -> (StringUtils.isEmpty(attribute.getNamespacePrefix())
                              && StringUtils.isEmpty(namespace))
                              || attribute.getNamespacePrefix().equals(namespace))
                      .map(ExtensionAttribute::getValue).findFirst().orElse(null);
          }
          return null;
      }
  
  }
  