/*
* 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.yangtools.yang.data.impl.schema.tree;
import com.google.common.base.Optional;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
/**
* Represents a {@link ModificationApplyOperation} which is rooted at conceptual
* top of data tree.
*
* <p>
* This implementation differs from other implementations in this package that
* is not immutable, but may be upgraded to newer state if available by
* explicitly invoking {@link #upgradeIfPossible()} and also serves as factory
* for deriving snapshot {@link RootModificationApplyOperation} which will not
* be affected by upgrade of original one.
*
* <p>
* There are two variations of this {@link ModificationApplyOperation}:
* <ul>
* <li>
* <b>Upgradable</b> - operation may be upgraded to different backing
* implementation by invoking {@link #upgradeIfPossible()}.</li>
* <li><b>Not Upgradable</b> - operation is immutable, invocation of
* {@link #upgradeIfPossible()} is no-op and method {@link #snapshot()} returns
* pointer on same object.
*
* <h3>Upgradable Root Modification Operation</h3>
*
* Upgradable Root Modification Operation may be created using:
* <ul>
* <li> {@link #from(ModificationApplyOperation)} with other upgradable root
* modification as an argument
* <li>using factory {@link LatestOperationHolder} which instantiates Upgradable
* Root Modification Operations and provides an option to set latest
* implementation.
* </ul>
* <p>
* Upgradable root operation is never upgraded to latest operation
* automatically, but client code must explicitly invoke
* {@link #upgradeIfPossible()} to get latest implementation.
*
* Note: This is helpful for implementing
* {@link org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification}
* which may be derived from
* {@link org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree} before
* update of schema and user actually writes data after schema update. During
* update user did not invoked any operation.
*
*/
abstract class RootModificationApplyOperation extends ModificationApplyOperation {
@Override
public final Optional<ModificationApplyOperation> getChild(final PathArgument child) {
return getDelegate().getChild(child);
}
@Override
final void checkApplicable(final YangInstanceIdentifier path, final NodeModification modification,
final Optional<TreeNode> current, final Version version) throws DataValidationFailedException {
getDelegate().checkApplicable(path, modification, current, version);
}
@Override
final Optional<TreeNode> apply(final ModifiedNode modification, final Optional<TreeNode> currentMeta,
final Version version) {
return getDelegate().apply(modification, currentMeta, version);
}
@Override
public final boolean equals(final Object obj) {
return getDelegate().equals(obj);
}
@Override
public final int hashCode() {
return getDelegate().hashCode();
}
@Override
public final String toString() {
return getDelegate().toString();
}
@Override
final void verifyStructure(final NormalizedNode<?, ?> modification, final boolean verifyChildren)
throws IllegalArgumentException {
getDelegate().verifyStructure(modification, verifyChildren);
}
@Override
void recursivelyVerifyStructure(NormalizedNode<?, ?> value) {
getDelegate().recursivelyVerifyStructure(value);
}
@Override
final ChildTrackingPolicy getChildPolicy() {
return getDelegate().getChildPolicy();
}
@Override
final void mergeIntoModifiedNode(final ModifiedNode node, final NormalizedNode<?, ?> value, final Version version) {
getDelegate().mergeIntoModifiedNode(node, value, version);
}
/**
* Return the underlying delegate.
*
* @return Underlying delegate.
*/
abstract ModificationApplyOperation getDelegate();
/**
* Creates a snapshot from this modification, which may have separate
* upgrade lifecycle and is not affected by upgrades
* <p>
* Newly created snapshot uses backing implementation of this modi
*
* @return Derived {@link RootModificationApplyOperation} with separate
* upgrade lifecycle.
*/
abstract RootModificationApplyOperation snapshot();
/**
* Upgrades backing implementation to latest available, if possible.
* <p>
* Latest implementation of {@link RootModificationApplyOperation} is
* managed by {@link LatestOperationHolder} which was used to construct this
* operation and latest operation is updated by
* {@link LatestOperationHolder#setCurrent(ModificationApplyOperation)}.
*/
abstract void upgradeIfPossible();
static RootModificationApplyOperation from(final ModificationApplyOperation resolver) {
if (resolver instanceof RootModificationApplyOperation) {
return ((RootModificationApplyOperation) resolver).snapshot();
}
return new NotUpgradableModificationApplyOperation(resolver);
}
}