package com.atlassian.plugins.rest.common.transaction;
   
   import com.atlassian.plugins.rest.common.interceptor.MethodInvocation;
   import com.atlassian.plugins.rest.common.interceptor.ResourceInterceptor;
   import com.atlassian.sal.api.transaction.TransactionCallback;
   import com.atlassian.sal.api.transaction.TransactionTemplate;
   
   import java.lang.reflect.InvocationTargetException;
   
  /**
   * Wraps the resource method call in a transaction via SAL's {@link TransactionTemplate}.
   *
   * @since 2.0
   */
  public class TransactionInterceptor implements ResourceInterceptor {
      private final TransactionTemplate transactionTemplate;
  
      public TransactionInterceptor(TransactionTemplate transactionTemplate) {
          this.transactionTemplate = transactionTemplate;
      }
  
      public void intercept(final MethodInvocation invocation) throws IllegalAccessException, InvocationTargetException {
          try {
              transactionTemplate.execute(new TransactionCallback() {
                  public Object doInTransaction() {
                      try {
                          invocation.invoke();
                      } catch (IllegalAccessException e) {
                          throw new TransactionException(e);
                      } catch (InvocationTargetException e) {
                          throw new TransactionException(e);
                      }
                      return null;
                  }
              });
          } catch (TransactionException ex) {
              Throwable t = ex.getCause();
              if (t instanceof IllegalAccessException) {
                  throw (IllegalAccessException) t;
              } else if (t instanceof InvocationTargetException) {
                  throw (InvocationTargetException) t;
              } else {
                  throw new RuntimeException("This should not be possible");
              }
          }
      }
  
      private static final class TransactionException extends RuntimeException {
          private TransactionException(Throwable throwable) {
              super(throwable);
          }
      }
  }