/*
* Copyright (c) 2015 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.model.api.stmt;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.UnmodifiableIterator;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.opendaylight.yangtools.concepts.Immutable;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.model.api.SchemaPath;
/**
* Represents unique path to the every schema node inside the schema node identifier namespace.
*/
public abstract class SchemaNodeIdentifier implements Immutable {
/**
* An absolute schema node identifier.
*/
public static final class Absolute extends SchemaNodeIdentifier {
private Absolute(final SchemaNodeIdentifier parent, final QName qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return true;
}
@Override
protected SchemaNodeIdentifier createInstance(final SchemaNodeIdentifier parent, final QName qname) {
return new Absolute(parent, Preconditions.checkNotNull(qname));
}
}
/**
* A relative schema node identifier.
*/
public static final class Relative extends SchemaNodeIdentifier {
private Relative(final SchemaNodeIdentifier parent, final QName qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return false;
}
@Override
protected SchemaNodeIdentifier createInstance(final SchemaNodeIdentifier parent, final QName qname) {
return new Relative(parent, Preconditions.checkNotNull(qname));
}
}
@SuppressWarnings("rawtypes")
private static final AtomicReferenceFieldUpdater<SchemaNodeIdentifier, ImmutableList> LEGACYPATH_UPDATER =
AtomicReferenceFieldUpdater.newUpdater(SchemaNodeIdentifier.class, ImmutableList.class, "legacyPath");
private static final AtomicReferenceFieldUpdater<SchemaNodeIdentifier, SchemaPath> SCHEMAPATH_UPDATER =
AtomicReferenceFieldUpdater.newUpdater(SchemaNodeIdentifier.class, SchemaPath.class, "schemaPath");
/**
* Shared instance of the conceptual root schema node.
*/
public static final SchemaNodeIdentifier ROOT = new Absolute(null, null);
/**
* Shared instance of the "same" relative schema node.
*/
public static final SchemaNodeIdentifier SAME = new Relative(null, null);
/**
* Parent path.
*/
private final SchemaNodeIdentifier parent;
/**
* This component.
*/
private final QName qname;
/**
* Cached hash code. We can use this since we are immutable.
*/
private final int hash;
/**
* Cached legacy path, filled-in when {@link #getPath()} or {@link #getPathTowardsRoot()}
* is invoked.
*/
private volatile ImmutableList<QName> legacyPath;
/**
* Cached SchemaPath.
*/
private volatile SchemaPath schemaPath;
protected SchemaNodeIdentifier(final SchemaNodeIdentifier parent, final QName qname) {
this.parent = parent;
this.qname = qname;
int h = Objects.hashCode(parent);
if (qname != null) {
h = h * 31 + qname.hashCode();
}
hash = h;
}
private ImmutableList<QName> getLegacyPath() {
ImmutableList<QName> ret = legacyPath;
if (ret == null) {
ret = ImmutableList.copyOf(getPathTowardsRoot()).reverse();
LEGACYPATH_UPDATER.lazySet(this, ret);
}
return ret;
}
/**
* Constructs new instance of this class with the concrete path.
*
* @param path
* list of QName instances which specifies exact path to the
* module node
* @param absolute
* boolean value which specifies if the path is absolute or
* relative
*
* @return A SchemaNodeIdentifier instance.
*/
public static SchemaNodeIdentifier create(final Iterable<QName> path, final boolean absolute) {
final SchemaNodeIdentifier parent = absolute ? ROOT : SAME;
return parent.createChild(path);
}
/**
* Constructs new instance of this class with the concrete path.
*
* @param absolute
* boolean value which specifies if the path is absolute or
* relative
* @param path
* one or more QName instances which specifies exact path to the
* module node
*
* @return A SchemaPath instance.
*/
public static SchemaNodeIdentifier create(final boolean absolute, final QName... path) {
return create(Arrays.asList(path), absolute);
}
/**
* Create a new instance.
*
* @param parent Parent schema node identifier
* @param qname next path element
* @return A new SchemaPath instance
*/
protected abstract SchemaNodeIdentifier createInstance(SchemaNodeIdentifier parent, QName qname);
/**
* Create a child path based on concatenation of this path and a relative path.
*
* @param relative Relative path
* @return A new child path
*/
public SchemaNodeIdentifier createChild(final Iterable<QName> relative) {
if (Iterables.isEmpty(relative)) {
return this;
}
SchemaNodeIdentifier parentNode = this;
for (QName qname : relative) {
parentNode = parentNode.createInstance(parentNode, qname);
}
return parentNode;
}
/**
* Create a child path based on concatenation of this path and a relative path.
*
* @param relative Relative SchemaPath
* @return A new child path
*/
public SchemaNodeIdentifier createChild(final SchemaNodeIdentifier relative) {
Preconditions.checkArgument(!relative.isAbsolute(), "Child creation requires relative path");
SchemaNodeIdentifier parentNode = this;
for (QName qname : relative.getPathFromRoot()) {
parentNode = parentNode.createInstance(parentNode, qname);
}
return parentNode;
}
/**
* Create a child path based on concatenation of this path and additional
* path elements.
*
* @param elements Relative SchemaPath elements
* @return A new child path
*/
public SchemaNodeIdentifier createChild(final QName... elements) {
return createChild(Arrays.asList(elements));
}
/**
* Returns the list of nodes which need to be traversed to get from the
* starting point (root for absolute SchemaPaths) to the node represented
* by this object.
*
* @return list of <code>qname</code> instances which represents
* path from the root to the schema node.
*/
public Iterable<QName> getPathFromRoot() {
return getLegacyPath();
}
/**
* Returns the list of nodes which need to be traversed to get from this
* node to the starting point (root for absolute SchemaPaths).
*
* @return list of <code>qname</code> instances which represents
* path from the schema node towards the root.
*/
public Iterable<QName> getPathTowardsRoot() {
return () -> new UnmodifiableIterator<QName>() {
private SchemaNodeIdentifier current = SchemaNodeIdentifier.this;
@Override
public boolean hasNext() {
return current.parent != null;
}
@Override
public QName next() {
if (current.parent != null) {
final QName ret = current.qname;
current = current.parent;
return ret;
} else {
throw new NoSuchElementException("No more elements available");
}
}
};
}
/**
* Returns the immediate parent SchemaPath.
*
* @return Parent path, null if this SchemaPath is already toplevel.
*/
public SchemaNodeIdentifier getParent() {
return parent;
}
/**
* Get the last component of this path.
*
* @return The last component of this path.
*/
public final QName getLastComponent() {
return qname;
}
private SchemaPath createSchemaPath() {
final SchemaPath newPath;
if (parent == null) {
final SchemaPath parentPath = isAbsolute() ? SchemaPath.ROOT : SchemaPath.SAME;
newPath = qname == null ? parentPath : parentPath.createChild(qname);
} else {
newPath = parent.asSchemaPath().createChild(qname);
}
return SCHEMAPATH_UPDATER.compareAndSet(this, null, newPath) ? newPath : schemaPath;
}
/**
* Create the {@link SchemaPath} equivalent of this identifier.
*
* @return SchemaPath equivalent.
*/
public final SchemaPath asSchemaPath() {
final SchemaPath ret = schemaPath;
return ret != null ? ret : createSchemaPath();
}
/**
* Describes whether schema node identifier is|isn't absolute.
*
* @return boolean value which is <code>true</code> if schema path is
* absolute.
*/
public abstract boolean isAbsolute();
@Override
public final int hashCode() {
return hash;
}
@Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final SchemaNodeIdentifier other = (SchemaNodeIdentifier) obj;
return Objects.equals(qname, other.qname) && Objects.equals(parent, other.parent);
}
@Override
public final String toString() {
return addToStringAttributes(MoreObjects.toStringHelper(this)).toString();
}
protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
return toStringHelper.add("path", getPathFromRoot());
}
}