Add a validator for the input string format.

src/main/java/space/kklochko/jdbc_hospital_example/cli/validators/InputStringFormatValidator.java

@@ -0,0 +1,21 @@
+package space.kklochko.jdbc_hospital_example.cli.validators;
+
+import java.util.regex.Pattern;
+
+public class InputStringFormatValidator extends Validator {
+    String command;
+    String formatRegEx = "\\w+\\s\\w+\\((|[^)]+)\\)";
+
+    public InputStringFormatValidator(String command) {
+        this.command = command;
+    }
+
+    public boolean isValid() {
+        Pattern pattern = Pattern.compile(formatRegEx);
+        return pattern.matcher(command).matches();
+    }
+
+    public String getMessage() {
+        return "Please, check the format: `command item(arg1=value1, ...)`. Or check the `help`";
+    }
+}

src/test/groovy/space/kklochko/jdbc_hospital_example/cli/validators/InputStringFormatValidatorSpec.groovy

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+package space.kklochko.jdbc_hospital_example.cli.validators
+
+import space.kklochko.jdbc_hospital_example.cli.commands.CommandData
+import space.kklochko.jdbc_hospital_example.cli.parsers.CommandParser
+import spock.lang.Specification
+import spock.lang.Subject
+
+class InputStringFormatValidatorSpec extends Specification {
+    def "Parser parse the commands"() {
+        given: "I have the validator"
+        @Subject
+        def validator = new InputStringFormatValidator(command)
+
+        when: "check if valid"
+        boolean status = validator.isValid()
+
+        then: "the result must be as expected"
+        status == expectedStatus
+
+        where:
+        command                                                                                                  || expectedStatus
+        "insert indicator(id='1', type='blood', values='Good samples.', timestamp='2023-10-17 14:30:00')"        || true
+        "insert indicator(id='1', type='blood, blood', values='Good samples.', timestamp='2023-10-17 14:30:00')" || true
+        "readAll indicator()"                                                                                    || true
+    }
+}