Added annotation NotBlank for String parameters

TODO.md

@@ -1,7 +1,11 @@
 - 1.5.0
 
-    - `@NotBlank` for Strings
-
+    - Remove deprecated Arbitrary.just()
+
+    - Generate documentation
+
+    - Release
+
 
 - 1.5.1
 

api/src/main/java/net/jqwik/api/constraints/NotBlank.java

@@ -0,0 +1,22 @@
+package net.jqwik.api.constraints;
+
+import java.lang.annotation.*;
+
+import org.apiguardian.api.*;
+
+import static org.apiguardian.api.API.Status.*;
+
+/**
+ * Constrain a string to never be blank, i.e. not empty and not just whitespace.
+ *
+ * Applies to String parameters which are also annotated with {@code @ForAll}.
+ *
+ * @see net.jqwik.api.ForAll
+ * @see NotEmpty
+ */
+@Target({ ElementType.ANNOTATION_TYPE, ElementType.PARAMETER, ElementType.TYPE_USE })
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@API(status = EXPERIMENTAL, since = "1.5.0")
+public @interface NotBlank {
+}

docs/release-notes.md

@@ -25,6 +25,8 @@ title: jqwik Release Notes
 
 #### New and Enhanced Features
 
+- Added constraint annotation `@NotBlank` for String parameters
+
 - Generated email addresses get a few more edge cases
 
 #### Breaking Changes
@@ -44,7 +46,7 @@ title: jqwik Release Notes
 - Some arbitrary types, e.g. `Arbitraries.lazyOf()` could not be used in sampling.
   Now all should work.
 
-- Bounded shrinking could result in an `OutsideJqwikException`.
+- Bounded shrinking could previously result in an `OutsideJqwikException`.
 
 
 ## 1.4.0

documentation/src/docs/include/default-parameter-generation.md

@@ -46,6 +46,12 @@ depending on the requested parameter type.
 - [`@NotEmpty`](/docs/${docsVersion}/javadoc/net/jqwik/api/constraints/NotEmpty.html):
   Set minimum length to `1`.
 
+#### String not Blank
+
+- [`@NotBlank`](/docs/${docsVersion}/javadoc/net/jqwik/api/constraints/NotBlank.html):
+  Strings must not be empty or only contain whitespace.
+
+
 #### Character Sets
 
 When generating chars any unicode character might be generated.

engine/src/main/java/net/jqwik/engine/properties/configurators/NotBlankConfigurator.java

@@ -0,0 +1,18 @@
+package net.jqwik.engine.properties.configurators;
+
+import net.jqwik.api.*;
+import net.jqwik.api.configurators.*;
+import net.jqwik.api.constraints.*;
+import net.jqwik.api.providers.*;
+
+public class NotBlankConfigurator extends ArbitraryConfiguratorBase {
+
+	@Override
+	protected boolean acceptTargetType(TypeUsage targetType) {
+		return targetType.isOfType(String.class);
+	}
+
+	public Arbitrary<String> configure(Arbitrary<String> arbitrary, NotBlank notBlank) {
+		return arbitrary.filter(s -> s != null && !s.trim().isEmpty());
+	}
+}

engine/src/main/resources/META-INF/services/net.jqwik.api.configurators.ArbitraryConfigurator

@@ -12,3 +12,4 @@ net.jqwik.engine.properties.configurators.BigDecimalRangeConfigurator
 net.jqwik.engine.properties.configurators.PositiveConfigurator
 net.jqwik.engine.properties.configurators.NegativeConfigurator
 net.jqwik.engine.properties.configurators.WhitespaceConfigurator
+net.jqwik.engine.properties.configurators.NotBlankConfigurator

engine/src/test/java/net/jqwik/api/constraints/NotBlankProperties.java

@@ -0,0 +1,30 @@
+package net.jqwik.api.constraints;
+
+import net.jqwik.api.*;
+
+class NotBlankProperties {
+
+	@Property
+	boolean aStringIsNeverBlank(@ForAll @NotBlank String aString) {
+		return isNotBlank(aString);
+	}
+
+	@Property
+	boolean aProvidedStringIsNeverBlank(@ForAll("provided") @NotBlank String aString) {
+		return isNotBlank(aString);
+	}
+
+	@Provide
+	Arbitrary<String> provided() {
+		return Arbitraries.strings().ofMaxLength(5);
+	}
+
+	@Property
+	void doesNotInfluenceNonStringArbitrary(@ForAll @NotBlank long aLong) {
+	}
+
+	private boolean isNotBlank(String aString) {
+		return aString != null && !aString.trim().isEmpty();
+	}
+
+}