content: package com.alibaba.qlexpress4.runtime.instruction;
  
  import com.alibaba.qlexpress4.QLOptions;
  import com.alibaba.qlexpress4.exception.ErrorReporter;
  import com.alibaba.qlexpress4.exception.QLErrorCodes;
  import com.alibaba.qlexpress4.exception.QLRuntimeException;
  import com.alibaba.qlexpress4.runtime.*;
  import com.alibaba.qlexpress4.runtime.util.ThrowUtils;
  import com.alibaba.qlexpress4.runtime.util.ValueUtils;
  import com.alibaba.qlexpress4.utils.PrintlnUtils;
  
  import java.util.List;
  import java.util.Map;
  import java.util.function.Consumer;
  
  /**
   * Operation: try and catch throw element
   * Input: 0
   * Output: 1
   *
   * Author: DQinYuan
   */
  public class TryCatchInstruction extends QLInstruction {
      
      private final QLambdaDefinition body;
      
      private final List<Map.Entry<Class<?>, QLambdaDefinition>> exceptionTable;
      
      private final QLambdaDefinition finalBody;
      
      public TryCatchInstruction(ErrorReporter errorReporter, QLambdaDefinition body,
          List<Map.Entry<Class<?>, QLambdaDefinition>> exceptionTable, QLambdaDefinition finalBody) {
          super(errorReporter);
          this.body = body;
          this.exceptionTable = exceptionTable;
          this.finalBody = finalBody;
      }
      
      @Override
      public QResult execute(QContext qContext, QLOptions qlOptions) {
          QResult tryCatchResult = tryCatchResult(qContext, qlOptions);
          Value resultValue = tryCatchResult.getResult();
          qContext.push(ValueUtils.toImmutable(resultValue));
          
          if (finalBody != null) {
              callFinal(qContext, qlOptions);
          }
          if (tryCatchResult.getResultType() == QResult.ResultType.RETURN) {
              return tryCatchResult;
          }
          return QResult.NEXT_INSTRUCTION;
      }
      
      @Override
      public int stackInput() {
          return 0;
      }
      
      @Override
      public int stackOutput() {
          return 1;
      }
      
      @Override
      public void println(int index, int depth, Consumer<String> debug) {
          PrintlnUtils.printlnByCurDepth(depth, index + ": TryCatch", debug);
          PrintlnUtils.printlnByCurDepth(depth + 1, "Body", debug);
          body.println(depth + 2, debug);
          for (Map.Entry<Class<?>, QLambdaDefinition> clsLambdaEn : exceptionTable) {
              PrintlnUtils.printlnByCurDepth(depth + 1, clsLambdaEn.getKey().getSimpleName(), debug);
              clsLambdaEn.getValue().println(depth + 2, debug);
          }
          if (finalBody != null) {
              PrintlnUtils.printlnByCurDepth(depth + 1, "Finally", debug);
              finalBody.println(depth + 2, debug);
          }
      }
      
      private void callFinal(QContext qContext, QLOptions qlOptions) {
          QLambda finalLambda = finalBody.toLambda(qContext, qlOptions, true);
          try {
              finalLambda.call();
          }
          catch (Throwable t) {
              throw ThrowUtils.wrapThrowable(t,
                  errorReporter,
                  QLErrorCodes.EXECUTE_FINAL_BLOCK_ERROR.name(),
                  QLErrorCodes.EXECUTE_FINAL_BLOCK_ERROR.getErrorMsg());
          }
      }
      
      private QResult tryCatchResult(QContext qContext, QLOptions qlOptions) {
          try {
              QLambda bodyLambda = body.toLambda(qContext, qlOptions, true);
              return bodyLambda.call();
          }
          catch (QLRuntimeException e) {
              Object catchObj = e.getCatchObj();
              if (catchObj == null) {
                  // ensure catch object can catch all exception
                  catchObj = new Object();
              }
              QResult result = callExceptionHandler(catchObj, qContext, qlOptions);
              if (result == null) {
                  throw e;
              }
              return result;
          }
          catch (Throwable t) {
              QResult result = callExceptionHandler(t, qContext, qlOptions);
              if (result == null) {
                  throw ThrowUtils.wrapThrowable(t,
                      errorReporter,
                      QLErrorCodes.EXECUTE_TRY_BLOCK_ERROR.name(),
                      QLErrorCodes.EXECUTE_TRY_BLOCK_ERROR.getErrorMsg());
              }
              return result;
          }
      }
      
      private QResult callExceptionHandler(Object catchObj, QContext qContext, QLOptions qlOptions) {
          QLambdaDefinition exceptionHandler = getExceptionHandler(catchObj.getClass());
          if (exceptionHandler == null) {
              return null;
          }
          QLambda catchHandlerLambda = exceptionHandler.toLambda(qContext, qlOptions, true);
          
          try {
              return catchHandlerLambda.call(catchObj);
          }
          catch (Throwable th) {
              throw ThrowUtils.wrapThrowable(th,
                  errorReporter,
                  QLErrorCodes.EXECUTE_CATCH_HANDLER_ERROR.name(),
                  QLErrorCodes.EXECUTE_CATCH_HANDLER_ERROR.getErrorMsg(),
                  catchObj.getClass().getName());
          }
      }
      
      private QLambdaDefinition getExceptionHandler(Class<?> catchObjClass) {
          for (Map.Entry<Class<?>, QLambdaDefinition> clsLambdaEn : exceptionTable) {
              if (clsLambdaEn.getKey().isAssignableFrom(catchObjClass)) {
                  return clsLambdaEn.getValue();
              }
          }
          return null;
      }
  }
  