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.runtime.*;
  import com.alibaba.qlexpress4.runtime.data.DataValue;
  import com.alibaba.qlexpress4.runtime.util.MethodInvokeUtils;
  import com.alibaba.qlexpress4.utils.PrintlnUtils;
  
  import java.util.function.Consumer;
  
  /**
   * Operation: invoke specified method of object on the top of stack
   * Input: ${argNum} + 1
   * Output: 1, method return value, null for void method
   * <p>
   * equivalent to GetMethodInstruction + CallInstruction
   * <p>
   * Author: DQinYuan
   */
  public class MethodInvokeInstruction extends QLInstruction {
      
      private final String methodName;
      
      private final int argNum;
      
      private final boolean optional;
      
      public MethodInvokeInstruction(ErrorReporter errorReporter, String methodName, int argNum, boolean optional) {
          super(errorReporter);
          this.methodName = methodName;
          this.argNum = argNum;
          this.optional = optional;
      }
      
      @Override
      public QResult execute(QContext qContext, QLOptions qlOptions) {
          Parameters parameters = qContext.pop(this.argNum + 1);
          Object bean = parameters.get(0).get();
          Class<?>[] type = new Class[this.argNum];
          Object[] params = new Object[this.argNum];
          for (int i = 0; i < this.argNum; i++) {
              Value v = parameters.get(i + 1);
              params[i] = v.get();
              type[i] = v.getType();
          }
          if (bean == null) {
              if (qlOptions.isAvoidNullPointer() || optional) {
                  qContext.push(DataValue.NULL_VALUE);
                  return QResult.NEXT_INSTRUCTION;
              }
              throw errorReporter.report(new NullPointerException(),
                  QLErrorCodes.NULL_METHOD_ACCESS.name(),
                  QLErrorCodes.NULL_METHOD_ACCESS.getErrorMsg());
          }
          Value invokeRes = MethodInvokeUtils
              .findMethodAndInvoke(bean, methodName, params, type, qContext.getReflectLoader(), errorReporter);
          qContext.push(invokeRes);
          return QResult.NEXT_INSTRUCTION;
      }
      
      @Override
      public int stackInput() {
          return argNum + 1;
      }
      
      @Override
      public int stackOutput() {
          return 1;
      }
      
      @Override
      public void println(int index, int depth, Consumer<String> debug) {
          PrintlnUtils.printlnByCurDepth(depth, index + ": MethodInvoke " + methodName + " with argNum " + argNum, debug);
      }
      
      public String getMethodName() {
          return methodName;
      }
      
  }
  