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.QContext;
  import com.alibaba.qlexpress4.runtime.QResult;
  import com.alibaba.qlexpress4.runtime.data.DataValue;
  import com.alibaba.qlexpress4.utils.PrintlnUtils;
  
  import java.util.function.Consumer;
  
  /**
   * Operation: pop the top of stack, if the element is ${expect}, jump to position, else execute next instruction as normal. jump if null
   * Input: 1
   * Output: 0
   *
   * Author: DQinYuan
   */
  public class JumpIfPopInstruction extends QLInstruction {
      
      private final boolean expect;
      
      private int position;
      
      public JumpIfPopInstruction(ErrorReporter errorReporter, boolean expect, int position) {
          super(errorReporter);
          this.expect = expect;
          this.position = position;
      }
      
      @Override
      public QResult execute(QContext qContext, QLOptions qlOptions) {
          boolean conditionBool = conditionToBool(qContext.pop().get());
          return conditionBool == expect ? new QResult(new DataValue(position), QResult.ResultType.JUMP)
              : QResult.NEXT_INSTRUCTION;
      }
      
      private boolean conditionToBool(Object condition) {
          if (condition == null) {
              return expect;
          }
          if (!(condition instanceof Boolean)) {
              throw errorReporter.report(QLErrorCodes.CONDITION_BOOL_REQUIRED.name(),
                  QLErrorCodes.CONDITION_BOOL_REQUIRED.getErrorMsg());
          }
          return (boolean)condition;
      }
      
      @Override
      public int stackInput() {
          return 1;
      }
      
      @Override
      public int stackOutput() {
          return 0;
      }
      
      public void setPosition(int position) {
          this.position = position;
      }
      
      @Override
      public void println(int index, int depth, Consumer<String> debug) {
          PrintlnUtils.printlnByCurDepth(depth, index + ": JumpIfPop " + expect + " " + position, debug);
      }
  }
  