1 files changed, 128 insertions, 0 deletions
diff --git a/framework/src/onos/core/net/src/main/java/org/onosproject/net/intent/impl/CompilerRegistry.java b/framework/src/onos/core/net/src/main/java/org/onosproject/net/intent/impl/CompilerRegistry.java
new file mode 100644
index 00000000..1b70bc67
--- /dev/null
+++ b/framework/src/onos/core/net/src/main/java/org/onosproject/net/intent/impl/CompilerRegistry.java
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.
+ */
+package org.onosproject.net.intent.impl;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+
+import org.onosproject.net.intent.Intent;
+import org.onosproject.net.intent.IntentCompiler;
+import org.onosproject.net.intent.IntentException;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+// TODO: consider a better name
+class CompilerRegistry {
+
+    private final ConcurrentMap<Class<? extends Intent>,
+            IntentCompiler<? extends Intent>> compilers = new ConcurrentHashMap<>();
+
+    /**
+     * Registers the specified compiler for the given intent class.
+     *
+     * @param cls      intent class
+     * @param compiler intent compiler
+     * @param <T>      the type of intent
+     */
+    public <T extends Intent> void registerCompiler(Class<T> cls, IntentCompiler<T> compiler) {
+        compilers.put(cls, compiler);
+    }
+
+    /**
+     * Unregisters the compiler for the specified intent class.
+     *
+     * @param cls intent class
+     * @param <T> the type of intent
+     */
+    public <T extends Intent> void unregisterCompiler(Class<T> cls) {
+        compilers.remove(cls);
+    }
+
+    /**
+     * Returns immutable set of bindings of currently registered intent compilers.
+     *
+     * @return the set of compiler bindings
+     */
+    public Map<Class<? extends Intent>, IntentCompiler<? extends Intent>> getCompilers() {
+        return ImmutableMap.copyOf(compilers);
+    }
+
+    /**
+     * Compiles an intent recursively.
+     *
+     * @param intent intent
+     * @param previousInstallables previous intent installables
+     * @return result of compilation
+     */
+    List<Intent> compile(Intent intent, List<Intent> previousInstallables) {
+        if (intent.isInstallable()) {
+            return ImmutableList.of(intent);
+        }
+
+        registerSubclassCompilerIfNeeded(intent);
+        // FIXME: get previous resources
+        List<Intent> installable = new ArrayList<>();
+        for (Intent compiled : getCompiler(intent).compile(intent, previousInstallables, null)) {
+            installable.addAll(compile(compiled, previousInstallables));
+        }
+        return installable;
+    }
+
+    /**
+     * Returns the corresponding intent compiler to the specified intent.
+     *
+     * @param intent intent
+     * @param <T>    the type of intent
+     * @return intent compiler corresponding to the specified intent
+     */
+    private <T extends Intent> IntentCompiler<T> getCompiler(T intent) {
+        @SuppressWarnings("unchecked")
+        IntentCompiler<T> compiler = (IntentCompiler<T>) compilers.get(intent.getClass());
+        if (compiler == null) {
+            throw new IntentException("no compiler for class " + intent.getClass());
+        }
+        return compiler;
+    }
+
+    /**
+     * Registers an intent compiler of the specified intent if an intent compiler
+     * for the intent is not registered. This method traverses the class hierarchy of
+     * the intent. Once an intent compiler for a parent type is found, this method
+     * registers the found intent compiler.
+     *
+     * @param intent intent
+     */
+    private void registerSubclassCompilerIfNeeded(Intent intent) {
+        if (!compilers.containsKey(intent.getClass())) {
+            Class<?> cls = intent.getClass();
+            while (cls != Object.class) {
+                // As long as we're within the Intent class descendants
+                if (Intent.class.isAssignableFrom(cls)) {
+                    IntentCompiler<?> compiler = compilers.get(cls);
+                    if (compiler != null) {
+                        compilers.put(intent.getClass(), compiler);
+                        return;
+                    }
+                }
+                cls = cls.getSuperclass();
+            }
+        }
+    }
+}