[isis] branch master updated: ISIS-3202: unrelated: adds ProperMixinAsReturnType as a design draft

[ah...@apache.org]

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ahuber pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/isis.git


The following commit(s) were added to refs/heads/master by this push:
     new 251a05c3df ISIS-3202: unrelated: adds ProperMixinAsReturnType as a design draft
251a05c3df is described below

commit 251a05c3dfc06cc630e977367b82bfbff180025e
Author: Andi Huber <ah...@apache.org>
AuthorDate: Sun Sep 4 06:01:44 2022 +0200

    ISIS-3202: unrelated: adds ProperMixinAsReturnType as a design draft
---
 .../java/org/apache/isis/applib/value/Clob.java    |   9 ++
 .../domainmodel/MetaModelRegressionTest.java       |   5 +-
 .../model/good/ProperMixinAsReturnType.java        | 104 +++++++++++++++++++++
 3 files changed, 114 insertions(+), 4 deletions(-)

diff --git a/api/applib/src/main/java/org/apache/isis/applib/value/Clob.java b/api/applib/src/main/java/org/apache/isis/applib/value/Clob.java
index 78642986b1..9b28921213 100644
--- a/api/applib/src/main/java/org/apache/isis/applib/value/Clob.java
+++ b/api/applib/src/main/java/org/apache/isis/applib/value/Clob.java
@@ -19,6 +19,7 @@
 package org.apache.isis.applib.value;
 
 import java.io.IOException;
+import java.io.StringWriter;
 import java.io.Writer;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
@@ -36,6 +37,7 @@ import org.apache.isis.applib.jaxb.PrimitiveJaxbAdapters;
 import org.apache.isis.commons.internal.base._Strings;
 
 import lombok.NonNull;
+import lombok.SneakyThrows;
 import lombok.val;
 
 /**
@@ -171,6 +173,13 @@ public final class Clob implements NamedWithMimeType {
         }
     }
 
+    @SneakyThrows
+    public String asString() {
+        val sw = new StringWriter();
+        writeCharsTo(sw);
+        return sw.toString();
+    }
+
     // -- OBJECT CONTRACT
 
     @Override
diff --git a/regressiontests/stable-domainmodel/src/test/java/org/apache/isis/testdomain/domainmodel/MetaModelRegressionTest.java b/regressiontests/stable-domainmodel/src/test/java/org/apache/isis/testdomain/domainmodel/MetaModelRegressionTest.java
index 388e18b56d..745f5e9482 100644
--- a/regressiontests/stable-domainmodel/src/test/java/org/apache/isis/testdomain/domainmodel/MetaModelRegressionTest.java
+++ b/regressiontests/stable-domainmodel/src/test/java/org/apache/isis/testdomain/domainmodel/MetaModelRegressionTest.java
@@ -19,7 +19,6 @@
 package org.apache.isis.testdomain.domainmodel;
 
 import java.io.IOException;
-import java.io.StringWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
 
@@ -92,9 +91,7 @@ class MetaModelRegressionTest {
 
     private static String asXml(final Blob zip) throws IOException {
         val clob = zip.unZip(CommonMimeType.XML).toClob(StandardCharsets.UTF_8);
-        val sw = new StringWriter();
-        clob.writeCharsTo(sw);
-        return sw.toString();
+        return clob.asString();
     }
 
     private Options options() {
diff --git a/regressiontests/stable/src/main/java/org/apache/isis/testdomain/model/good/ProperMixinAsReturnType.java b/regressiontests/stable/src/main/java/org/apache/isis/testdomain/model/good/ProperMixinAsReturnType.java
new file mode 100644
index 0000000000..90dc4f7eb2
--- /dev/null
+++ b/regressiontests/stable/src/main/java/org/apache/isis/testdomain/model/good/ProperMixinAsReturnType.java
@@ -0,0 +1,104 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.isis.testdomain.model.good;
+
+import java.time.LocalDate;
+import java.util.Random;
+
+import javax.inject.Inject;
+
+import org.apache.isis.applib.annotation.Action;
+import org.apache.isis.applib.annotation.Domain;
+import org.apache.isis.applib.annotation.DomainObject;
+import org.apache.isis.applib.annotation.MemberSupport;
+import org.apache.isis.applib.annotation.Nature;
+import org.apache.isis.applib.annotation.Parameter;
+import org.apache.isis.applib.annotation.Property;
+import org.apache.isis.applib.services.factory.FactoryService;
+import org.apache.isis.testdomain.model.interaction.InteractionDemoItem;
+
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * A draft:
+ * <p>
+ * Without any addition to existing programming model annotations, I could think
+ * of adding a new feature, that is to allow for actions to return mixin
+ * instances. In this example you see an action updateDemoItemGeneric that
+ * randomly chooses between 2 different mixed in actions, which to return: its
+ * either updateDemoItemName or updateDemoItemDate both mixins implementing the
+ * 'I am a mixin' marker interface DemoItemUpdateMixin. The meta-model figures
+ * out on type inspection (compile time types that is) which types are mixin
+ * types. Hence the marker interface.
+ * <p>
+ * instead of having to define a marker interface yourself, the framework could
+ * just provide one out of the box for this use-case. Something along those
+ * lines: interface MixinAsReturnType {} with special semantics, that is, those
+ * stay hidden in the UI and are only considered as action return types.
+ *
+ * @see "https://the-asf.slack.com/archives/CFC42LWBV/p1662261916803059?thread_ts=1661485836.027909&cid=CFC42LWBV"
+ */
+@Domain.Exclude// just a draft
+//@Named("testdomain.ProperMixinAsReturnType")
+//@DomainObject(nature = Nature.VIEW_MODEL)
+public class ProperMixinAsReturnType {
+
+    @Inject
+    FactoryService factoryService;
+
+    @Property
+    @Getter
+    @Setter
+    private InteractionDemoItem demoItem;
+
+    @Action
+    public MixinAsReturnType updateDemoItemGeneric() {
+        return new Random().nextBoolean()
+                ? factoryService.mixin(ProperMixinAsReturnType.updateDemoItemName.class, this)
+                : factoryService.mixin(ProperMixinAsReturnType.updateDemoItemDate.class, this);
+    }
+
+    // -- MIXINS
+
+    @DomainObject(nature = Nature.MIXIN)
+    interface MixinAsReturnType {
+    }
+
+    @Action
+    public class updateDemoItemName implements MixinAsReturnType {
+
+        @MemberSupport
+        public ProperMixinAsReturnType act(@Parameter final String newName) {
+            demoItem.setName(newName);
+            return ProperMixinAsReturnType.this;
+        }
+    }
+
+    @Action
+    public class updateDemoItemDate implements MixinAsReturnType {
+
+        @MemberSupport
+        public ProperMixinAsReturnType act(@Parameter final LocalDate newDate) {
+            demoItem.setDate(newDate);
+            return ProperMixinAsReturnType.this;
+        }
+    }
+
+}