content: /*
   * Copyright (C) 2010-2101 Alibaba Group Holding Limited.
   *
   * 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 com.alibaba.otter.shared.common.utils.extension;
  
  import org.apache.commons.lang.StringUtils;
  
  import com.alibaba.otter.shared.common.model.config.data.ExtensionData;
  import com.alibaba.otter.shared.common.utils.cache.ExtensionMemoryMirror;
  import com.alibaba.otter.shared.common.utils.cache.ExtensionMemoryMirror.ComputeFunction;
  import com.alibaba.otter.shared.common.utils.compile.impl.JdkCompiler;
  import com.alibaba.otter.shared.common.utils.compile.model.JavaSource;
  import com.alibaba.otter.shared.common.utils.extension.classpath.ClassScanner;
  import com.alibaba.otter.shared.common.utils.extension.exceptions.ExtensionLoadException;
  
  /**
   * @author jianghang 2012-11-7 下午02:11:46
   * @version 4.1.2
   */
  public class DefaultExtensionFactory implements ExtensionFactory {
  
      private ExtensionMemoryMirror<ExtensionData, Object> resolverCache;
      private ClassScanner                                 classPathScanner;
      private ClassScanner                                 fileSystemScanner;
      private JdkCompiler                                  jdkCompiler;
  
      public DefaultExtensionFactory(){
          resolverCache = new ExtensionMemoryMirror<ExtensionData, Object>(new ComputeFunction<ExtensionData, Object>() {
  
              public Object apply(ExtensionData extensionData) {
                  return getExtensionInternal(extensionData);
              }
          });
      }
  
      public <T> T getExtension(Class<T> type, ExtensionData extensionData) {
          return (T) resolverCache.get(extensionData);
      }
  
      private Object getExtensionInternal(ExtensionData extensionData) {
          Class<?> clazz = null;
          String fullname = StringUtils.EMPTY;
  
          if (extensionData.getExtensionDataType().isClazz() && StringUtils.isNotBlank(extensionData.getClazzPath())) {
              clazz = scan(extensionData.getClazzPath());
              fullname = "[" + extensionData.getClazzPath() + "]ClassPath";
          } else if (extensionData.getExtensionDataType().isSource()
                     && StringUtils.isNotBlank(extensionData.getSourceText())) {
              JavaSource javaSource = new JavaSource(extensionData.getSourceText());
              clazz = jdkCompiler.compile(javaSource);
              fullname = "[" + javaSource.toString() + "]SourceText";
          }
  
          if (clazz == null) {
              throw new ExtensionLoadException("ERROR ## classload this fileresolver=" + fullname + " has an error");
          }
  
          try {
              return clazz.newInstance();
          } catch (Exception e) {
              throw new ExtensionLoadException("ERROR ## classload this fileresolver=" + fullname + " has an error", e);
          }
      }
  
      private Class scan(String fileResolverClassname) {
          Class<?> clazz = classPathScanner.scan(fileResolverClassname);
          if (clazz == null) {
              clazz = fileSystemScanner.scan(fileResolverClassname);
          }
  
          return clazz;
      }
  
      // =============setter / getter===============
  
      public void setClassPathScanner(ClassScanner classPathScanner) {
          this.classPathScanner = classPathScanner;
      }
  
      public void setFileSystemScanner(ClassScanner fileSystemScanner) {
          this.fileSystemScanner = fileSystemScanner;
      }
  
      public ClassScanner getFileSystemScanner() {
          return fileSystemScanner;
      }
  
      public void setJdkCompiler(JdkCompiler jdkCompiler) {
          this.jdkCompiler = jdkCompiler;
      }
  
  }
  