package com.atlassian.scheduler.cron;
   
   import com.atlassian.scheduler.SchedulerServiceException;
   
   import javax.annotation.Nonnull;
   import javax.annotation.Nullable;
   
   import static com.google.common.base.MoreObjects.firstNonNull;
   
  /**
   * Signals that there is a syntax error in a given cron expression.
   *
   * @since v1.4
   */
  @SuppressWarnings("SerializableHasSerializationMethods")
  public class CronSyntaxException extends SchedulerServiceException {
      private static final long serialVersionUID = 5594187147397941674L;
  
      private final ErrorCode errorCode;
      private final String cronExpression;
      private final String value;
      private final int errorOffset;
  
      /**
       * Internal constructor.  Use a {@link #builder() builder} to construct these.
       */
      CronSyntaxException(final Builder builder) {
          super(builder.toMessage());
          this.errorCode = firstNonNull(builder.errorCode, ErrorCode.INTERNAL_PARSER_FAILURE);
          this.cronExpression = firstNonNull(builder.cronExpression, "");
          this.value = builder.value;
          this.errorOffset = builder.errorOffset;
          if (builder.cause != null) {
              initCause(builder.cause);
          }
      }
  
      /**
       * Returns the error code identifying the underlying cause of the parse failure.
       *
       * @return the error code identifying the underlying cause of the parse failure.
       */
      @Nonnull
      public ErrorCode getErrorCode() {
          return errorCode;
      }
  
      /**
       * Returns the cron expression that could not be parsed.
       *
       * @return the cron expression that could not be parsed.
       */
      @Nonnull
      public String getCronExpression() {
          return cronExpression;
      }
  
      /**
       * Returns the value that caused the exception to be thrown, if that information is available.
       * For example, if the day-of-month field specified {@code 4,10-13,42-47}, then the value would be {@code "42"}
       * because {@code 31} is the maximum value permitted for that field.
       *
       * @return the value that caused the exception to be thrown, or {@code null} if that is irrelevant to the
       * error or if the cause is unknown
       */
      @Nullable
      public String getValue() {
          return value;
      }
  
      /**
       * Returns the {@code 0}-based index of the character at which the parse error was identified.
       *
       * @return the {@code 0}-based index of the character at which the parse error was identified,
       * or {@code -1} if the index is not known.
       */
      public int getErrorOffset() {
          return errorOffset;
      }
  
      /**
       * Returns a builder for constructing a {@code CronSyntaxExpression}.
       *
       * @return a builder for constructing a {@code CronSyntaxExpression}.
       */
      public static Builder builder() {
          return new Builder();
      }
  
  
      /**
       * A builder for constructing a {@link com.atlassian.scheduler.cron.CronSyntaxException}.
       */
      public static class Builder {
          String cronExpression;
          String value;
          ErrorCode errorCode;
          int errorOffset = -1;
          Throwable cause;
 
         Builder() {
         }
 
         /**
          * Sets the cron expression that caused the exception.
          * If left unspecified, then {@code ""} is used.
          */
         public Builder cronExpression(@Nullable String cronExpression) {
             this.cronExpression = cronExpression;
             return this;
         }
 
         /**
          * Sets the value that caused the exception.
          * For example, if the month field contained {@code FEB-XYZ}, then {@code "XYZ"} should be set for the value.
          */
         public Builder value(@Nullable String value) {
             this.value = value;
             return this;
         }
 
         /**
          * Sets the value that caused the exception.
          * This convenience method is equivalent to {@link #value(String) value(String.valueOf(value))}.
          */
         public Builder value(char value) {
             this.value = String.valueOf(value);
             return this;
         }
 
         /**
          * Sets the error code for the exception.
          * If left unspecified, then {@link ErrorCode#INTERNAL_PARSER_FAILURE} is used.
          */
         public Builder errorCode(@Nullable ErrorCode errorCode) {
             this.errorCode = errorCode;
             return this;
         }
 
         /**
          * Sets the error code for the exception.
          * If left unspecified, then {@code -1} is used.
          */
         public Builder errorOffset(int errorOffset) {
             this.errorOffset = (errorOffset >= 0) ? errorOffset : -1;
             return this;
         }
 
         /**
          * Sets the cause of the exception.
          */
         public Builder cause(@Nullable Throwable cause) {
             this.cause = cause;
             return this;
         }
 
         /**
          * Returns the completed exception.
          *
          * @return the completed exception.
          */
         public CronSyntaxException build() {
             return new CronSyntaxException(this);
         }
 
         @Nonnull
         String toMessage() {
             return errorCode.toMessage(value);
         }
     }
 }