src/main/java/net/hostsharing/hsadminng/hs/booking/item/validators/HsBookingItemEntityValidator.java

@@ -16,7 +16,7 @@ import static java.util.Optional.ofNullable;
 
 public class HsBookingItemEntityValidator extends HsEntityValidator<HsBookingItemEntity> {
 
-    public HsBookingItemEntityValidator(final ValidatableProperty<?>... properties) {
+    public HsBookingItemEntityValidator(final ValidatableProperty<?, ?>... properties) {
         super(properties);
     }
 
@@ -54,7 +54,7 @@ public class HsBookingItemEntityValidator extends HsEntityValidator<HsBookingIte
     // TODO.refa: convert into generic shape like multi-options validator
     private static String validateMaxTotalValue(
             final HsBookingItemEntity bookingItem,
-            final ValidatableProperty<?> propDef) {
+            final ValidatableProperty<?, ?> propDef) {
         final var propName = propDef.propertyName();
         final var propUnit = ofNullable(propDef.unit()).map(u -> " " + u).orElse("");
         final var totalValue = ofNullable(bookingItem.getSubBookingItems()).orElse(emptyList())

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsHostingAssetEntityValidator.java

@@ -24,7 +24,7 @@ import static java.util.Optional.ofNullable;
 
 public abstract class HsHostingAssetEntityValidator extends HsEntityValidator<HsHostingAssetEntity> {
 
-    static final ValidatableProperty<?>[] NO_EXTRA_PROPERTIES = new ValidatableProperty<?>[0];
+    static final ValidatableProperty<?, ?>[] NO_EXTRA_PROPERTIES = new ValidatableProperty<?, ?>[0];
 
     private final HsHostingAssetEntityValidator.BookingItem bookingItemValidation;
     private final HsHostingAssetEntityValidator.ParentAsset parentAssetValidation;
@@ -36,7 +36,7 @@ public abstract class HsHostingAssetEntityValidator extends HsEntityValidator<Hs
             @NotNull final ParentAsset parentAssetValidation,
             @NotNull final AssignedToAsset assignedToAssetValidation,
             @NotNull final AlarmContact alarmContactValidation,
-            final ValidatableProperty<?>... properties) {
+            final ValidatableProperty<?, ?>... properties) {
         super(properties);
         this.bookingItemValidation = bookingItemValidation;
         this.parentAssetValidation = parentAssetValidation;
@@ -105,7 +105,7 @@ public abstract class HsHostingAssetEntityValidator extends HsEntityValidator<Hs
     // TODO.test: check, if there are any hosting assets which need this validation at all
     private String validateMaxTotalValue(
             final HsHostingAssetEntity hostingAsset,
-            final ValidatableProperty<?> propDef) {
+            final ValidatableProperty<?, ?> propDef) {
         final var propName = propDef.propertyName();
         final var propUnit = ofNullable(propDef.unit()).map(u -> " " + u).orElse("");
         final var totalValue = ofNullable(hostingAsset.getSubHostingAssets()).orElse(emptyList())

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsUnixUserHostingAssetValidator.java

@@ -30,7 +30,7 @@ class HsUnixUserHostingAssetValidator extends HsHostingAssetEntityValidator {
                         .withDefault("/bin/false"),
                 stringProperty("homedir").readOnly().computedBy(HsUnixUserHostingAssetValidator::computeHomedir),
                 stringProperty("totpKey").matchesRegEx("^0x([0-9A-Fa-f]{2})+$").minLength(20).maxLength(256).undisclosed().writeOnly().optional(),
-                passwordProperty("password").minLength(8).maxLength(40).writeOnly());
+                passwordProperty("password").minLength(8).maxLength(40).hashedUsing("SHA-512").writeOnly());
     }
 
     @Override

src/main/java/net/hostsharing/hsadminng/hs/validation/BooleanProperty.java

@@ -9,7 +9,7 @@ import java.util.Map;
 import java.util.Objects;
 
 @Setter
-public class BooleanProperty extends ValidatableProperty<Boolean> {
+public class BooleanProperty extends ValidatableProperty<BooleanProperty, Boolean> {
 
     private static final String[] KEY_ORDER = Array.join(ValidatableProperty.KEY_ORDER_HEAD, ValidatableProperty.KEY_ORDER_TAIL);
 
@@ -23,7 +23,7 @@ public class BooleanProperty extends ValidatableProperty<Boolean> {
         return new BooleanProperty(propertyName);
     }
 
-    public ValidatableProperty<Boolean> falseIf(final String refPropertyName, final String refPropertyValue) {
+    public BooleanProperty falseIf(final String refPropertyName, final String refPropertyValue) {
         this.falseIf = new AbstractMap.SimpleImmutableEntry<>(refPropertyName, refPropertyValue);
         return this;
     }

src/main/java/net/hostsharing/hsadminng/hs/validation/EnumerationProperty.java

@@ -9,7 +9,7 @@ import java.util.List;
 import static java.util.Arrays.stream;
 
 @Setter
-public class EnumerationProperty extends ValidatableProperty<String> {
+public class EnumerationProperty extends ValidatableProperty<EnumerationProperty, String> {
 
     private static final String[] KEY_ORDER = Array.join(
             ValidatableProperty.KEY_ORDER_HEAD,
@@ -26,12 +26,12 @@ public class EnumerationProperty extends ValidatableProperty<String> {
         return new EnumerationProperty(propertyName);
     }
 
-    public ValidatableProperty<String> values(final String... values) {
+    public EnumerationProperty values(final String... values) {
         this.values = values;
         return this;
     }
 
-    public void deferredInit(final ValidatableProperty<?>[] allProperties) {
+    public void deferredInit(final ValidatableProperty<?, ?>[] allProperties) {
         if (hasDeferredInit()) {
             if (this.values != null) {
                 throw new IllegalStateException("property " + this + " already has values");
@@ -40,8 +40,8 @@ public class EnumerationProperty extends ValidatableProperty<String> {
         }
     }
 
-    public ValidatableProperty<String> valuesFromProperties(final String propertyNamePrefix) {
-        this.setDeferredInit( (ValidatableProperty<?>[] allProperties) -> stream(allProperties)
+    public EnumerationProperty valuesFromProperties(final String propertyNamePrefix) {
+        this.setDeferredInit( (ValidatableProperty<?, ?>[] allProperties) -> stream(allProperties)
                 .map(ValidatableProperty::propertyName)
                 .filter(name -> name.startsWith(propertyNamePrefix))
                 .map(name -> name.substring(propertyNamePrefix.length()))

src/main/java/net/hostsharing/hsadminng/hs/validation/HsEntityValidator.java

@@ -14,9 +14,9 @@ import static java.util.Collections.emptyList;
 // TODO.refa: rename to HsEntityProcessor, also subclasses
 public abstract class HsEntityValidator<E extends PropertiesProvider> {
 
-    public final ValidatableProperty<?>[] propertyValidators;
+    public final ValidatableProperty<?, ?>[] propertyValidators;
 
-    public HsEntityValidator(final ValidatableProperty<?>... validators) {
+    public HsEntityValidator(final ValidatableProperty<?, ?>... validators) {
         propertyValidators = validators;
         stream(propertyValidators).forEach(p -> p.deferredInit(propertyValidators));
     }
@@ -68,7 +68,7 @@ public abstract class HsEntityValidator<E extends PropertiesProvider> {
                 .orElse(emptyList()));
     }
 
-    protected static Integer getIntegerValueWithDefault0(final ValidatableProperty<?> prop, final Map<String, Object> propValues) {
+    protected static Integer getIntegerValueWithDefault0(final ValidatableProperty<?, ?> prop, final Map<String, Object> propValues) {
         final var value = prop.getValue(propValues);
         if (value instanceof Integer) {
             return (Integer) value;

src/main/java/net/hostsharing/hsadminng/hs/validation/IntegerProperty.java

@@ -7,7 +7,7 @@ import org.apache.commons.lang3.Validate;
 import java.util.List;
 
 @Setter
-public class IntegerProperty extends ValidatableProperty<Integer> {
+public class IntegerProperty extends ValidatableProperty<IntegerProperty, Integer> {
 
     private final static String[] KEY_ORDER = Array.join(
             ValidatableProperty.KEY_ORDER_HEAD,
@@ -30,7 +30,7 @@ public class IntegerProperty extends ValidatableProperty<Integer> {
     }
 
     @Override
-    public void deferredInit(final ValidatableProperty<?>[] allProperties) {
+    public void deferredInit(final ValidatableProperty<?, ?>[] allProperties) {
         Validate.isTrue(min == null || minFrom == null, "min and minFrom are exclusive, but both are given");
         Validate.isTrue(max == null || maxFrom == null, "max and maxFrom are exclusive, but both are given");
     }

src/main/java/net/hostsharing/hsadminng/hs/validation/PasswordProperty.java

@@ -6,7 +6,7 @@ import java.util.List;
 import java.util.stream.Stream;
 
 @Setter
-public class PasswordProperty extends StringProperty {
+public class PasswordProperty extends StringProperty<PasswordProperty> {
 
     private PasswordProperty(final String propertyName) {
         super(propertyName);
@@ -23,7 +23,9 @@ public class PasswordProperty extends StringProperty {
         validatePassword(result, propValue);
     }
 
-    // TODO.impl: only a SHA512 hash should be stored in the database, not the password itself
+    public PasswordProperty hashedUsing(final String hashAlgoritm) {
+        return self();
+    }
 
     @Override
     protected String simpleTypeName() {
@@ -60,6 +62,5 @@ public class PasswordProperty extends StringProperty {
         if (containsColon) {
             result.add(propertyName + "' must not contain colon (':')");
         }
-
     }
 }

src/main/java/net/hostsharing/hsadminng/hs/validation/StringProperty.java

@@ -8,7 +8,7 @@ import java.util.regex.Pattern;
 
 
 @Setter
-public class StringProperty extends ValidatableProperty<String> {
+public class StringProperty<P extends StringProperty<P>> extends ValidatableProperty<P, String> {
 
     private static final String[] KEY_ORDER = Array.join(
             ValidatableProperty.KEY_ORDER_HEAD,
@@ -24,23 +24,23 @@ public class StringProperty extends ValidatableProperty<String> {
         super(String.class, propertyName, KEY_ORDER);
     }
 
-    public static StringProperty stringProperty(final String propertyName) {
-        return new StringProperty(propertyName);
+    public static StringProperty<?> stringProperty(final String propertyName) {
+        return new StringProperty<>(propertyName);
     }
 
-    public StringProperty minLength(final int minLength) {
+    public P minLength(final int minLength) {
         this.minLength = minLength;
-        return this;
+        return self();
     }
 
-    public StringProperty maxLength(final int maxLength) {
+    public P maxLength(final int maxLength) {
         this.maxLength = maxLength;
-        return this;
+        return self();
     }
 
-    public StringProperty matchesRegEx(final String regExPattern) {
+    public P matchesRegEx(final String regExPattern) {
         this.matchesRegEx = Pattern.compile(regExPattern);
-        return this;
+        return self();
     }
 
     /**
@@ -48,9 +48,9 @@ public class StringProperty extends ValidatableProperty<String> {
      *
      * @return this;
      */
-    public StringProperty undisclosed() {
+    public P undisclosed() {
         this.undisclosed = true;
-        return this;
+        return self();
     }
 
     @Override

src/main/java/net/hostsharing/hsadminng/hs/validation/ValidatableProperty.java

@@ -25,7 +25,7 @@ import static java.util.Optional.ofNullable;
 
 @Getter
 @RequiredArgsConstructor
-public abstract class ValidatableProperty<T> {
+public abstract class ValidatableProperty<P extends ValidatableProperty<?, ?>, T> {
 
     protected static final String[] KEY_ORDER_HEAD = Array.of("propertyName");
     protected static final String[] KEY_ORDER_TAIL = Array.of("required", "defaultValue", "readOnly", "writeOnly", "computed", "isTotalsValidator", "thresholdPercentage");
@@ -51,7 +51,7 @@ public abstract class ValidatableProperty<T> {
     @Accessors(makeFinal = true, chain = true, fluent = false)
     private boolean writeOnly;
 
-    private Function<ValidatableProperty<?>[], T[]> deferredInit;
+    private Function<ValidatableProperty<?, ?>[], T[]> deferredInit;
     private boolean isTotalsValidator = false;
 
     @JsonIgnore
@@ -59,11 +59,16 @@ public abstract class ValidatableProperty<T> {
 
     private Integer thresholdPercentage; // TODO.impl: move to IntegerProperty
 
+    public final P self() {
+        //noinspection unchecked
+        return (P) this;
+    }
+
     public String unit() {
         return null;
     }
 
-    protected void setDeferredInit(final Function<ValidatableProperty<?>[], T[]> function) {
+protected void setDeferredInit(final Function<ValidatableProperty<?, ?>[], T[]> function) {
         this.deferredInit = function;
     }
 
@@ -71,47 +76,47 @@ public abstract class ValidatableProperty<T> {
         return deferredInit != null;
     }
 
-    public T[] doDeferredInit(final ValidatableProperty<?>[] allProperties) {
+    public T[] doDeferredInit(final ValidatableProperty<?, ?>[] allProperties) {
         return deferredInit.apply(allProperties);
     }
 
-    public ValidatableProperty<T> writeOnly() {
+    public P writeOnly() {
         this.writeOnly = true;
         optional();
-        return this;
+        return self();
     }
 
-    public ValidatableProperty<T> readOnly() {
+    public P readOnly() {
         this.readOnly = true;
         optional();
-        return this;
+        return self();
     }
 
-    public ValidatableProperty<T> required() {
+    public P required() {
         required = TRUE;
-        return this;
+        return self();
     }
 
-    public ValidatableProperty<T> optional() {
+    public ValidatableProperty<P, T> optional() {
         required = FALSE;
         return this;
     }
 
-    public ValidatableProperty<T> withDefault(final T value) {
+    public P withDefault(final T value) {
         defaultValue = value;
         required = FALSE;
-        return this;
+        return self();
     }
 
-    public void deferredInit(final ValidatableProperty<?>[] allProperties) {
+    public void deferredInit(final ValidatableProperty<?, ?>[] allProperties) {
     }
 
-    public ValidatableProperty<T> asTotalLimit() {
+    public P asTotalLimit() {
         isTotalsValidator = true;
-        return this;
+        return self();
     }
 
-    public ValidatableProperty<T> asTotalLimitFor(final String propertyName, final String propertyValue) {
+    public P asTotalLimitFor(final String propertyName, final String propertyValue) {
         if (asTotalLimitValidators == null) {
             asTotalLimitValidators = new ArrayList<>();
         }
@@ -132,7 +137,7 @@ public abstract class ValidatableProperty<T> {
             return emptyList();
         };
         asTotalLimitValidators.add((final HsBookingItemEntity entity) -> validator.apply(entity, (IntegerProperty)this,  1));
-        return this;
+        return self();
     }
 
     public String propertyName() {
@@ -147,7 +152,7 @@ public abstract class ValidatableProperty<T> {
         return thresholdPercentage;
     }
 
-    public ValidatableProperty<T> eachComprising(final int factor, final TriFunction<HsBookingItemEntity, IntegerProperty, Integer, List<String>> validator) {
+    public ValidatableProperty<P, T> eachComprising(final int factor, final TriFunction<HsBookingItemEntity, IntegerProperty, Integer, List<String>> validator) {
         if (asTotalLimitValidators == null) {
             asTotalLimitValidators = new ArrayList<>();
         }
@@ -155,9 +160,9 @@ public abstract class ValidatableProperty<T> {
         return this;
     }
 
-    public ValidatableProperty<?> withThreshold(final Integer percentage) {
+    public P withThreshold(final Integer percentage) {
         this.thresholdPercentage = percentage;
-        return this;
+        return self();
     }
 
     public final List<String> validate(final PropertiesProvider propsProvider) {
@@ -250,10 +255,10 @@ public abstract class ValidatableProperty<T> {
                 .toList();
     }
 
-    public ValidatableProperty<T> computedBy(final Function<PropertiesProvider, T> compute) {
+    public P computedBy(final Function<PropertiesProvider, T> compute) {
         this.computedBy = compute;
         this.computed = true;
-        return this;
+        return self();
     }
 
     public <E extends PropertiesProvider> T compute(final E entity) {

src/test/java/net/hostsharing/hsadminng/hs/validation/PasswordPropertyUnitTest.java

@@ -12,7 +12,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 class PasswordPropertyUnitTest {
 
-    private final ValidatableProperty<String> passwordProp = passwordProperty("password").minLength(8).maxLength(40).writeOnly();
+    private final ValidatableProperty<PasswordProperty, String> passwordProp = passwordProperty("password").minLength(8).maxLength(40).writeOnly();
     private final List<String> violations = new ArrayList<>();
 
     @ParameterizedTest