Use a utility function for key-value to map conversions

[netvirt.git] / utils / yang-utils / src / main / java / org / opendaylight / ovsdb / utils / yang / YangUtils.java

diff --git a/utils/yang-utils/src/main/java/org/opendaylight/ovsdb/utils/yang/YangUtils.java b/utils/yang-utils/src/main/java/org/opendaylight/ovsdb/utils/yang/YangUtils.java
new file mode 100644 (file)
index 0000000..6470e6f
--- /dev/null
+++ b/utils/yang-utils/src/main/java/org/opendaylight/ovsdb/utils/yang/YangUtils.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright © 2016 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.ovsdb.utils.yang;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * YANG utility functions.
+ */
+public final class YangUtils {
+    /**
+     * Prevent instantiation.
+     */
+    private YangUtils() {
+        // Nothing to do
+    }
+
+    /**
+     * Copies a list of YANG key-value items to the given map. Any {@code null} key or value will cause an error.
+     *
+     * @param map The map to fill.
+     * @param yangList The list of YANG key-value items.
+     * @param keyExtractor The key extractor function to use.
+     * @param valueExtractor The value extractor function to use.
+     * @param <T> The YANG item type.
+     * @param <K> The key type.
+     * @param <V> The value type.
+     * @return The map.
+     */
+    @Nonnull
+    public static <T, K, V> Map<K, V> copyYangKeyValueListToMap(@Nonnull Map<K, V> map, @Nullable Iterable<T> yangList,
+                                                                @Nonnull Function<T, K> keyExtractor,
+                                                                @Nonnull Function<T, V> valueExtractor) {
+        if (yangList != null) {
+            for (T yangValue : yangList) {
+                K key = keyExtractor.apply(yangValue);
+                V value = valueExtractor.apply(yangValue);
+                Preconditions.checkNotNull(key);
+                Preconditions.checkNotNull(value);
+                map.put(key, value);
+            }
+        }
+        return map;
+    }
+
+    /**
+     * Converts a list of YANG key-value items to a map.
+     *
+     * @param yangList The list of YANG key-value items.
+     * @param keyExtractor The key extractor function to use.
+     * @param valueExtractor The value extractor function to use.
+     * @param <T> The YANG item type.
+     * @param <K> The key type.
+     * @param <V> The value type.
+     * @return The map.
+     */
+    @Nonnull
+    public static <T, K, V> Map<K, V> convertYangKeyValueListToMap(@Nullable Iterable<T> yangList,
+                                                                   @Nonnull Function<T, K> keyExtractor,
+                                                                   @Nonnull Function<T, V> valueExtractor) {
+        return copyYangKeyValueListToMap(new HashMap<>(), yangList, keyExtractor, valueExtractor);
+    }
+}