Add the Derived Property Element and its example

.gitmodules

@@ -11,3 +11,6 @@
 [submodule "pipeline/pipeline.core/configuration-validation"]
 	path = pipeline/pipeline.core/configuration-validation
 	url = ../configuration-validation
+[submodule "pipeline/derived-properties"]
+	path = pipeline/derived-properties
+	url = ../derived-properties

AGENTS.md

@@ -294,6 +294,14 @@ The Windows pre-build scripts take a toolset and SDK version from the pom.
 JavaScript templates and the OWID library are submodules inside `pipeline`,
 where the Pipeline API expects them.
 
+`pipeline/derived-properties` is the
+[derived-properties](https://github.com/51Degrees/derived-properties)
+repository. `pipeline.derivedproperty` packages the scripts in its `scripts`
+folder as resources, so a script added there needs a `BuiltInScript`
+constant, which `BuiltInScriptTests` checks. The package's tests run every
+case file and every rejection case in its `tests` folder, so its answers and
+its faults are checked against the other languages'.
+
 ## Releases
 
 Pull requests go to `rc`, not `main`, and stay drafts until they have been

ci/packages.json

@@ -8,6 +8,7 @@
   {"Name": "pipeline.cloudrequestengine", "Path": "pipeline/pipeline.cloudrequestengine", "DependsOn": ["pipeline", "pipeline.engines", "pipeline.common"], "Publish": true},
   {"Name": "pipeline.engines.fiftyone", "Path": "pipeline/pipeline.engines.fiftyone", "DependsOn": ["pipeline", "pipeline.engines", "pipeline.common"], "Publish": true},
   {"Name": "pipeline.translation", "Path": "pipeline/pipeline.translation", "DependsOn": ["pipeline", "pipeline.engines", "pipeline.core"], "Publish": true},
+  {"Name": "pipeline.derivedproperty", "Path": "pipeline/pipeline.derivedproperty", "ExtraPaths": ["pipeline/derived-properties"], "DependsOn": ["pipeline", "pipeline.engines", "pipeline.core"], "Publish": true},
   {"Name": "pipeline.javascriptbuilder", "Path": "pipeline/pipeline.javascriptbuilder", "DependsOn": ["pipeline", "pipeline.jsonbuilder", "pipeline.engines", "pipeline.common"], "Publish": true},
   {"Name": "pipeline.jsonbuilder", "Path": "pipeline/pipeline.jsonbuilder", "DependsOn": ["pipeline", "pipeline.engines.fiftyone", "pipeline.common", "pipeline.engines"], "Publish": true},
   {"Name": "pipeline.web.packages", "Path": "pipeline/pipeline.web.packages/pom.xml", "DependsOn": ["pipeline"], "Publish": true},
@@ -24,6 +25,7 @@
   {"Name": "pipeline.developerexamples.clientsideelement.mvc", "Path": "pipeline/pipeline.developer-examples/pipeline.developer-examples.clientside-element-mvc", "DependsOn": ["pipeline.developer-examples", "pipeline.developerexamples.clientsideelement", "pipeline.web.mvc", "pipeline.developerexamples.web.shared"], "Publish": true, "Ignore": ["pipeline/pipeline.developer-examples/**"]},
   {"Name": "pipeline.developerexamples.usagesharing", "Path": "pipeline/pipeline.developer-examples/pipeline.developer-examples.usage-sharing", "DependsOn": ["pipeline.developer-examples", "pipeline.engines.fiftyone"], "Publish": true, "Ignore": ["pipeline/pipeline.developer-examples/**"]},
   {"Name": "pipeline.developerexamples.fodid", "Path": "pipeline/pipeline.developer-examples/pipeline.developer-examples.fodid", "DependsOn": ["pipeline.developer-examples", "pipeline.did"], "Publish": true, "Ignore": ["pipeline/pipeline.developer-examples/**"]},
+  {"Name": "pipeline.developerexamples.derivedproperty", "Path": "pipeline/pipeline.developer-examples/pipeline.developer-examples.derivedproperty", "DependsOn": ["pipeline.developer-examples", "pipeline.derivedproperty"], "Publish": true, "Ignore": ["pipeline/pipeline.developer-examples/**"]},
   {"Name": "pipeline.device-detection", "Path": "device-detection/pom.xml", "DependsOn": ["pipeline-aggregate"], "Publish": true},
   {"Name": "device-detection.shared", "Path": "device-detection/device-detection.shared", "DependsOn": ["pipeline.device-detection", "pipeline.engines.fiftyone"], "Publish": true},
   {"Name": "device-detection.hash.engine.on-premise", "Path": "device-detection/device-detection.hash.engine.on-premise", "ExtraPaths": ["cxx"], "DependsOn": ["pipeline.device-detection", "device-detection.shared"], "Publish": true},

pipeline/README.md

@@ -28,6 +28,7 @@ but additional caution should be applied.
 - pipeline.engines - Shared functionality that is available to all 'engines' (specialized 'flow elements')
 - pipeline.engines.fiftyone - Functionality that is specific to 51Degrees engines.
 - pipeline.cloudrequestengine - An engine that is used to retrieve data from 51Degrees' cloud API.
+- pipeline.derivedproperty - The Derived Property Element, which produces new properties from the properties other elements produce, following rules written in a script.
 
 ## Installation
 

pipeline/pipeline.derivedproperty/pom.xml

@@ -0,0 +1,86 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ This Original Work is copyright of 51 Degrees Mobile Experts Limited.
+  ~ Copyright 2026 51 Degrees Mobile Experts Limited, Davidson House,
+  ~ Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
+  ~
+  ~ This Original Work is licensed under the European Union Public Licence
+  ~  (EUPL) v.1.2 and is subject to its terms as set out below.
+  ~
+  ~  If a copy of the EUPL was not distributed with this file, You can obtain
+  ~  one at https://opensource.org/licenses/EUPL-1.2.
+  ~
+  ~  The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
+  ~  amended by the European Commission) shall be deemed incompatible for
+  ~  the purposes of the Work and the provisions of the compatibility
+  ~  clause in Article 5 of the EUPL shall not apply.
+  ~
+  ~   If using the Work as, or as part of, a network application, by
+  ~   including the attribution notice(s) required under Article 5 of the EUPL
+  ~   in the end user terms of the application under an appropriate heading,
+  ~   such notice(s) shall fulfill the requirements of that article.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.51degrees</groupId>
+        <artifactId>pipeline</artifactId>
+        <version>4.5.127-SNAPSHOT</version>
+    </parent>
+    <artifactId>pipeline.derivedproperty</artifactId>
+    <packaging>jar</packaging>
+
+    <name>51Degrees :: Pipeline :: Derived Property</name>
+    <description>The Derived Property Element produces new property values from property values other elements in the Pipeline have already produced, following rules written in a script.</description>
+    <url>https://github.com/51Degrees/51degrees-java</url>
+
+    <dependencies>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>pipeline.engines</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>pipeline.core</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <!-- Scripts are read with the compose API, which gives every node
+             its line, and plain scalars are resolved here by the YAML 1.2
+             core schema, so "yes" stays the string "yes". -->
+        <dependency>
+            <groupId>org.yaml</groupId>
+            <artifactId>snakeyaml</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+            </resource>
+            <!-- The built-in scripts, straight from the derived-properties
+                 submodule rather than a copy. BuiltInScript names each one,
+                 and BuiltInScriptTests fails when the two differ. -->
+            <resource>
+                <directory>../derived-properties/scripts</directory>
+                <targetPath>fiftyone/pipeline/derivedproperty/scripts</targetPath>
+                <includes>
+                    <include>*.yaml</include>
+                    <include>*.yml</include>
+                    <include>*.json</include>
+                </includes>
+            </resource>
+        </resources>
+    </build>
+</project>

pipeline/pipeline.derivedproperty/src/main/java/fiftyone/pipeline/derivedproperty/BuiltInScript.java

@@ -0,0 +1,127 @@
+/* *********************************************************************
+ * This Original Work is copyright of 51 Degrees Mobile Experts Limited.
+ * Copyright 2026 51 Degrees Mobile Experts Limited, Davidson House,
+ * Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
+ *
+ * This Original Work is licensed under the European Union Public Licence
+ * (EUPL) v.1.2 and is subject to its terms as set out below.
+ *
+ * If a copy of the EUPL was not distributed with this file, You can obtain
+ * one at https://opensource.org/licenses/EUPL-1.2.
+ *
+ * The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
+ * amended by the European Commission) shall be deemed incompatible for
+ * the purposes of the Work and the provisions of the compatibility
+ * clause in Article 5 of the EUPL shall not apply.
+ *
+ * If using the Work as, or as part of, a network application, by
+ * including the attribution notice(s) required under Article 5 of the EUPL
+ * in the end user terms of the application under an appropriate heading,
+ * such notice(s) shall fulfill the requirements of that article.
+ * ********************************************************************* */
+
+package fiftyone.pipeline.derivedproperty;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Names every script shipped in this package. The scripts are the
+ * {@code scripts} folder of the derived-properties repository, and each
+ * constant is named exactly as its script is, so {@link #name()} is the
+ * script's name.
+ */
+public enum BuiltInScript {
+
+    /**
+     * The confidence that the request came from a device being used by a
+     * human who is viewing the page, being High, Medium, Low or Unknown.
+     */
+    HumanConfidence,
+
+    /**
+     * Whether the General Data Protection Regulation, or the United
+     * Kingdom's version of it, is likely to apply to the person making the
+     * request, judged from ip.CountryCode.
+     */
+    IsGdpr;
+
+    /**
+     * The folder on the class path the scripts are packaged in.
+     */
+    public static final String RESOURCE_FOLDER =
+        "/fiftyone/pipeline/derivedproperty/scripts/";
+
+    /**
+     * The file extensions a script is read from, in the order tried.
+     */
+    private static final String[] EXTENSIONS = {".yaml", ".yml", ".json"};
+
+    /**
+     * The size of each read from the packaged script.
+     */
+    private static final int BUFFER_BYTES = 8192;
+
+    /**
+     * The text of the script, read from the package.
+     * @return the text, or null where the package was built without the
+     * script
+     */
+    public String readText() {
+        for (String extension : EXTENSIONS) {
+            try (InputStream stream = BuiltInScript.class.getResourceAsStream(
+                RESOURCE_FOLDER + name() + extension)) {
+                if (stream != null) {
+                    return readAll(stream);
+                }
+            } catch (IOException e) {
+                throw new UncheckedIOException(
+                    "The built-in script '" + name() + "' cannot be read.",
+                    e);
+            }
+        }
+        return null;
+    }
+
+    /**
+     * The built-in script with the name given, matched exactly.
+     * @param name the script's name
+     * @return the script, or null where no built-in script has the name
+     */
+    public static BuiltInScript fromName(String name) {
+        for (BuiltInScript script : values()) {
+            if (script.name().equals(name)) {
+                return script;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Every built-in script's name, for a message.
+     * @return the names, separated by a comma and a space
+     */
+    public static String names() {
+        StringBuilder names = new StringBuilder();
+        for (BuiltInScript script : values()) {
+            if (names.length() > 0) {
+                names.append(", ");
+            }
+            names.append(script.name());
+        }
+        return names.toString();
+    }
+
+    private static String readAll(InputStream stream) throws IOException {
+        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+        byte[] buffer = new byte[BUFFER_BYTES];
+        int read;
+        while ((read = stream.read(buffer)) > 0) {
+            bytes.write(buffer, 0, read);
+        }
+        return new String(bytes.toByteArray(), StandardCharsets.UTF_8);
+    }
+}

pipeline/pipeline.derivedproperty/src/main/java/fiftyone/pipeline/derivedproperty/DerivedScriptFault.java

@@ -0,0 +1,112 @@
+/* *********************************************************************
+ * This Original Work is copyright of 51 Degrees Mobile Experts Limited.
+ * Copyright 2026 51 Degrees Mobile Experts Limited, Davidson House,
+ * Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
+ *
+ * This Original Work is licensed under the European Union Public Licence
+ * (EUPL) v.1.2 and is subject to its terms as set out below.
+ *
+ * If a copy of the EUPL was not distributed with this file, You can obtain
+ * one at https://opensource.org/licenses/EUPL-1.2.
+ *
+ * The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
+ * amended by the European Commission) shall be deemed incompatible for
+ * the purposes of the Work and the provisions of the compatibility
+ * clause in Article 5 of the EUPL shall not apply.
+ *
+ * If using the Work as, or as part of, a network application, by
+ * including the attribution notice(s) required under Article 5 of the EUPL
+ * in the end user terms of the application under an appropriate heading,
+ * such notice(s) shall fulfill the requirements of that article.
+ * ********************************************************************* */
+
+package fiftyone.pipeline.derivedproperty;
+
+import java.io.Serializable;
+
+/**
+ * One thing wrong with a derived property script.
+ */
+public final class DerivedScriptFault implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private final String script;
+    private final String source;
+    private final String path;
+    private final int line;
+    private final String message;
+
+    /**
+     * Construct a fault.
+     * @param script the name the script was given, or empty where it had
+     *               none
+     * @param source the built-in script's name, the file path, or "code"
+     * @param path the place in the document, such as Rules[3].When.All[1],
+     *             or empty for the document as a whole
+     * @param line the one based line, or 0 where the parser gave none
+     * @param message what is wrong
+     */
+    public DerivedScriptFault(
+        String script,
+        String source,
+        String path,
+        int line,
+        String message) {
+        this.script = script == null ? "" : script;
+        this.source = source == null ? "" : source;
+        this.path = path == null ? "" : path;
+        this.line = line;
+        this.message = message;
+    }
+
+    /**
+     * @return the name the script was given, or empty where it had none
+     */
+    public String getScript() {
+        return script;
+    }
+
+    /**
+     * @return the built-in script's name, the file path, or "code"
+     */
+    public String getSource() {
+        return source;
+    }
+
+    /**
+     * @return the place in the document, such as Rules[3].When.All[1], or
+     * empty for the document as a whole
+     */
+    public String getPath() {
+        return path;
+    }
+
+    /**
+     * @return the one based line, or 0 where the parser gave none
+     */
+    public int getLine() {
+        return line;
+    }
+
+    /**
+     * @return what is wrong
+     */
+    public String getMessage() {
+        return message;
+    }
+
+    /**
+     * The fault as one line, giving the script, the source, the line where
+     * known, the path and the message.
+     * @return the fault as one line
+     */
+    @Override
+    public String toString() {
+        return (script.isEmpty() ? "script" : script) +
+            " (" + source + ")" +
+            (line > 0 ? " line " + line : "") +
+            " at " + (path.isEmpty() ? "(document)" : path) +
+            ": " + message;
+    }
+}