Bug 499: Initial implementation of supporting tree structures
[controller.git] / opendaylight / md-sal / sal-dom-broker / src / main / java / org / opendaylight / controller / md / sal / dom / store / impl / tree / NodeModification.java
diff --git a/opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/tree/NodeModification.java b/opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/tree/NodeModification.java
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+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * 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.controller.md.sal.dom.store.impl.tree;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.opendaylight.yangtools.concepts.Identifiable;
+import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.PathArgument;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+
+import com.google.common.base.Optional;
+
+/**
+ * Node Modification Node and Tree
+ *
+ * Tree which structurally resembles data tree and captures client modifications
+ * to the data store tree.
+ *
+ * This tree is lazily created and populated via {@link #modifyChild(PathArgument)}
+ * and {@link StoreMetadataNode} which represents original state {@link #getOriginal()}.
+ *
+ */
+public class NodeModification implements StoreTreeNode<NodeModification>, Identifiable<PathArgument> {
+
+    private final PathArgument identifier;
+    private ModificationType modificationType = ModificationType.UNMODIFIED;
+
+
+    private final Optional<StoreMetadataNode> original;
+
+    private NormalizedNode<?, ?> value;
+
+    private StoreMetadataNode snapshotCache;
+
+    private final Map<PathArgument, NodeModification> childModification;
+
+    private boolean sealed = false;
+
+    protected NodeModification(final PathArgument identifier, final Optional<StoreMetadataNode> original) {
+        this.identifier = identifier;
+        this.original = original;
+        childModification = new LinkedHashMap<>();
+    }
+
+    /**
+     *
+     *
+     * @return
+     */
+    public NormalizedNode<?, ?> getWritenValue() {
+        return value;
+    }
+
+    @Override
+    public PathArgument getIdentifier() {
+        return identifier;
+    }
+
+    /**
+     *
+     * Returns original store metadata
+     * @return original store metadata
+     */
+    public final Optional<StoreMetadataNode> getOriginal() {
+        return original;
+    }
+
+    /**
+     * Returns modification type
+     *
+     * @return modification type
+     */
+    public final ModificationType getModificationType() {
+        return modificationType;
+    }
+
+    /**
+     *
+     * Returns child modification if child was modified
+     *
+     * @return Child modification if direct child or it's subtree
+     *  was modified.
+     *
+     */
+    @Override
+    public Optional<NodeModification> getChild(final PathArgument child) {
+        return Optional.<NodeModification> fromNullable(childModification.get(child));
+    }
+
+    /**
+     *
+     * Returns child modification if child was modified, creates {@link NodeModification}
+     * for child otherwise.
+     *
+     * If this node's {@link ModificationType} is {@link ModificationType#UNMODIFIED}
+     * changes modification type to {@link ModificationType#SUBTREE_MODIFIED}
+     *
+     * @param child
+     * @return {@link NodeModification} for specified child, with {@link #getOriginal()}
+     *  containing child metadata if child was present in original data.
+     */
+    public synchronized NodeModification modifyChild(final PathArgument child) {
+        checkSealed();
+        if(modificationType == ModificationType.UNMODIFIED) {
+            updateModificationType(ModificationType.SUBTREE_MODIFIED);
+        }
+        final NodeModification potential = childModification.get(child);
+        if (potential != null) {
+            return potential;
+        }
+        Optional<StoreMetadataNode> currentMetadata = Optional.absent();
+        if(original.isPresent()) {
+            currentMetadata = original.get().getChild(child);
+        }
+        NodeModification newlyCreated = new NodeModification(child,currentMetadata);
+        childModification.put(child, newlyCreated);
+        return newlyCreated;
+    }
+
+    /**
+     *
+     * Returns all recorded direct child modification
+     *
+     * @return all recorded direct child modifications
+     */
+    public Iterable<NodeModification> getModifications() {
+        return childModification.values();
+    }
+
+
+    /**
+     *
+     * Records a delete for associated node.
+     *
+     */
+    public synchronized void delete() {
+        checkSealed();
+        updateModificationType(ModificationType.DELETE);
+        childModification.clear();
+        this.value = null;
+    }
+
+    /**
+     *
+     * Records a write for associated node.
+     *
+     * @param value
+     */
+    public synchronized void write(final NormalizedNode<?, ?> value) {
+        checkSealed();
+        updateModificationType(ModificationType.WRITE);
+        childModification.clear();
+        this.value = value;
+    }
+
+    private void checkSealed() {
+        checkState(!sealed, "Node Modification is sealed. No further changes allowed.");
+    }
+
+    public synchronized void seal() {
+        sealed = true;
+        for(NodeModification child : childModification.values()) {
+            child.seal();
+        }
+    }
+
+    private void clearSnapshot() {
+        snapshotCache = null;
+    }
+
+    public boolean hasAdditionalModifications() {
+        return !childModification.isEmpty();
+    }
+
+    public void updateModificationType(final ModificationType type) {
+        modificationType = type;
+        clearSnapshot();
+    }
+
+    @Override
+    public String toString() {
+        return "NodeModification [identifier=" + identifier + ", modificationType="
+                + modificationType + ", value=" + value + ", childModification=" + childModification + "]";
+    }
+
+    public static NodeModification createUnmodified(final StoreMetadataNode metadataTree) {
+        return new NodeModification(metadataTree.getIdentifier(), Optional.of(metadataTree));
+    }
+
+}