=== Regular expressions

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There are three elements related to enforcing regular expressions:

* The xref:applib:index/annotation/Property.adoc#regexPattern[regexPattern()] element validates the contents of any string property with respect to a regular expression pattern.
It is ignored if applied to properties of any other type.

* The xref:applib:index/annotation/Property.adoc#regexPatternFlags[regexPatternFlags()] element specifies flags that modify the handling of the pattern.
The values are those that would normally be passed to `java.util.regex.Pattern#compile(String,int)`.

* The xref:applib:index/annotation/Property.adoc#regexPatternReplacement[regexPatternReplacement()] attribute specifies the error message to show if the provided argument does not match the regex pattern.

For example:

[source,java]
----
import lombok.Getter;
import lombok.Setter;

public class Customer {

    @Property(
        regexPattern = "(\\w+\\.)*\\w+@(\\w+\\.)+[A-Za-z]+",
        regexPatternFlags=Pattern.CASE_INSENSITIVE,
        regexPatternReplacement =
            "Must be valid email address (containing a '@') symbol"   // <.>
    )
    @Getter @Setter
    private String email;
}
----
<.> Note that there is currently no i18n support for this phrase.

== See also

This attribute can also be specified for xref:refguide:applib:index/annotation/Parameter.adoc#regexPattern[parameters].

