## Add regular expressions { #add-regular-expressions }

You can define a <abbr title="A regular expression, regex or regexp is a sequence of characters that define a search pattern for strings.">regular expression</abbr> `pattern` that the parameter should match:

{* ../../docs_src/query_params_str_validations/tutorial004_an_py310.py hl[11] *}

This specific regular expression pattern checks that the received parameter value:

    }

    /**
     * Splits the given string into an array of substrings based on the specified regular expression
     * and returns a stream of those substrings.
     *
     * @param value the string to be split; if {@code null}, the method returns an empty stream
     * @param regex the regular expression to use for splitting the string

			builder.WriteByte(')')
		}
	} else {
		builder.WriteString("DEFAULT VALUES")
	}
}

// MergeClause merge values clauses
func (values Values) MergeClause(clause *Clause) {
	clause.Name = ""
	clause.Expression = values

		queryDB      = tx
		rowsAffected int64
		batch        int
	)

	// user specified offset or limit
	var totalSize int
	if c, ok := tx.Statement.Clauses["LIMIT"]; ok {
		if limit, ok := c.Expression.(clause.Limit); ok {
			if limit.Limit != nil {
				totalSize = *limit.Limit
			}

			if totalSize > 0 && batchSize > totalSize {
				batchSize = totalSize
			}

	}

	if locking.Options != "" {
		builder.WriteByte(' ')
		builder.WriteString(locking.Options)
	}
}

// MergeClause merge order by clauses
func (locking Locking) MergeClause(clause *Clause) {
	clause.Expression = locking

	builder.WriteString("DELETE")

	if d.Modifier != "" {
		builder.WriteByte(' ')
		builder.WriteString(d.Modifier)
	}
}

func (d Delete) MergeClause(clause *Clause) {
	clause.Name = ""
	clause.Expression = d

import org.apache.maven.project.path.PathTranslator;
import org.codehaus.plexus.interpolation.Interpolator;
import org.codehaus.plexus.interpolation.RegexBasedInterpolator;

/**
 * Use a regular expression search to find and resolve expressions within the POM.
 *
 * TODO Consolidate this logic with the PluginParameterExpressionEvaluator, minus deprecations/bans.
 */
@Deprecated

    /** Current page number for pagination. */
    private int currentPageNumber;

    /** Boost document ID for search filtering. */
    public String id;

    /** URL expression for search filtering. */
    public String urlExpr;

    /** Boost expression for search filtering. */
    public String boostExpr;

    /** Sort order for search filtering. */
    public String sortOrder;

	}

	for _, join := range from.Joins {
		builder.WriteByte(' ')
		join.Build(builder)
	}
}

// MergeClause merge from clause
func (from From) MergeClause(clause *Clause) {
	clause.Expression = from

 * <p>Null nodes are strictly forbidden.
 *
 * <p>Because this is an abstract class, not an interface, you can't use a lambda expression to
 * implement it:
 *
 * {@snippet :
 * // won't work
 * TreeTraverser<NodeType> traverser = node -> node.getChildNodes();
 * }
 *
 * Instead, you can pass a lambda expression to the {@code using} factory method:
 *
 * {@snippet :