1 files changed, 166 insertions, 0 deletions
diff --git a/model/basic-model/src/main/java/org/onap/policy/apex/model/basicmodel/handling/ApexSchemaGenerator.java b/model/basic-model/src/main/java/org/onap/policy/apex/model/basicmodel/handling/ApexSchemaGenerator.java
new file mode 100644
index 000000000..6e17ab94d
--- /dev/null
+++ b/model/basic-model/src/main/java/org/onap/policy/apex/model/basicmodel/handling/ApexSchemaGenerator.java
@@ -0,0 +1,166 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * Licensed 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.
+ * 
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.apex.model.basicmodel.handling;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintStream;
+import java.io.StringWriter;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+import javax.xml.bind.SchemaOutputResolver;
+import javax.xml.transform.Result;
+import javax.xml.transform.stream.StreamResult;
+
+import org.slf4j.ext.XLogger;
+import org.slf4j.ext.XLoggerFactory;
+
+/**
+ * This class generates the XML model schema from the given Apex concept classes.
+ *
+ * @author Liam Fallon (liam.fallon@ericsson.com)
+ */
+public class ApexSchemaGenerator {
+    // Get a reference to the logger
+    private static final XLogger LOGGER = XLoggerFactory.getXLogger(ApexSchemaGenerator.class);
+
+    /**
+     * A Main method to allow schema generation from the command line or from maven or scripts.
+     *
+     * @param args the command line arguments, usage is {@code ApexSchemaGenerator apex-root-class [schema-file-name]}
+     */
+    public static void main(final String[] args) {
+        PrintStream printStream = null;
+
+        if (args.length == 1) {
+            printStream = System.out;
+        }
+        else if (args.length == 2) {
+            final File schemaFile = new File(args[1]);
+
+            try {
+                schemaFile.getParentFile().mkdirs();
+                printStream = new PrintStream(schemaFile);
+            }
+            catch (final Exception e) {
+                LOGGER.error("error on Apex schema output", e);
+                return;
+            }
+        }
+        else {
+            LOGGER.error("usage: ApexSchemaGenerator apex-root-class [schema-file-name]");
+            return;
+        }
+
+        // Get the schema
+        final String schema = new ApexSchemaGenerator().generate(args[0]);
+
+        // Output the schema
+        printStream.println(schema);
+
+        printStream.close();
+    }
+
+    /**
+     * Generates the XML schema (XSD) for the Apex model described using JAXB annotations.
+     *
+     * @param rootClassName the name of the root class for schema generation
+     * @return The schema
+     */
+    public String generate(final String rootClassName) {
+        JAXBContext jaxbContext;
+        try {
+            jaxbContext = JAXBContext.newInstance(Class.forName(rootClassName));
+        }
+        catch (final ClassNotFoundException e) {
+            LOGGER.error("could not create JAXB context, root class " + rootClassName + " not found", e);
+            return null;
+        }
+        catch (final JAXBException e) {
+            LOGGER.error("could not create JAXB context", e);
+            return null;
+        }
+
+        final ApexSchemaOutputResolver sor = new ApexSchemaOutputResolver();
+        try {
+            jaxbContext.generateSchema(sor);
+        }
+        catch (final IOException e) {
+            LOGGER.error("error generating the Apex schema (XSD) file", e);
+            return null;
+        }
+
+        String schemaString = sor.getSchema();
+        schemaString = fixForUnqualifiedBug(schemaString);
+
+        return schemaString;
+    }
+
+    /**
+     * There is a bug in schema generation that does not specify the elements from Java Maps as being unqualified. This method "hacks" those
+     * elements in the schema to fix this, the elements being {@code entry}, {@code key}, and {@code value}
+     *
+     * @param schemaString The schema in which elements should be fixed
+     * @return the string
+     */
+    private String fixForUnqualifiedBug(final String schemaString) {
+        // Fix the "entry" element
+        String newSchemaString = schemaString.replaceAll("<xs:element name=\"entry\" minOccurs=\"0\" maxOccurs=\"unbounded\">",
+                "<xs:element name=\"entry\" minOccurs=\"0\" maxOccurs=\"unbounded\" form=\"unqualified\">");
+
+        // Fix the "key" element
+        newSchemaString = newSchemaString.replaceAll("<xs:element name=\"key\"", "<xs:element name=\"key\" form=\"unqualified\"");
+
+        // Fix the "value" element
+        newSchemaString = newSchemaString.replaceAll("<xs:element name=\"value\"", "<xs:element name=\"value\" form=\"unqualified\"");
+
+        return newSchemaString;
+    }
+
+    /**
+     * This inner class is used to receive the output of schema generation from the JAXB schema generator.
+     */
+    private class ApexSchemaOutputResolver extends SchemaOutputResolver {
+        private final StringWriter stringWriter = new StringWriter();
+
+        /*
+         * (non-Javadoc)
+         *
+         * @see javax.xml.bind.SchemaOutputResolver#createOutput(java.lang.String, java.lang.String)
+         */
+        @Override
+        public Result createOutput(final String namespaceURI, final String suggestedFileName) throws IOException {
+            final StreamResult result = new StreamResult(stringWriter);
+            result.setSystemId(suggestedFileName);
+            return result;
+        }
+
+        /**
+         * Get the schema from the string writer created in the {@link createOutput()} method.
+         *
+         * @return the schema generated by JAXB
+         */
+        public String getSchema() {
+            return stringWriter.toString();
+        }
+    }
+}