/*
* Copyright (c) 2013 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;
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.Lists;
import com.google.common.collect.UnmodifiableIterator;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
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;
/**
* Represents unique path to the every node inside the module.
*/
public abstract class SchemaPath implements Immutable {
/**
* An absolute SchemaPath.
*/
private static final class AbsoluteSchemaPath extends SchemaPath {
private AbsoluteSchemaPath(final SchemaPath parent, final QName qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return true;
}
@Override
protected SchemaPath createInstance(final SchemaPath parent, final QName qname) {
return new AbsoluteSchemaPath(parent, Preconditions.checkNotNull(qname));
}
}
/**
* A relative SchemaPath.
*/
private static final class RelativeSchemaPath extends SchemaPath {
private RelativeSchemaPath(final SchemaPath parent, final QName qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return false;
}
@Override
protected SchemaPath createInstance(final SchemaPath parent, final QName qname) {
return new RelativeSchemaPath(parent, Preconditions.checkNotNull(qname));
}
}
@SuppressWarnings("rawtypes")
private static final AtomicReferenceFieldUpdater<SchemaPath, ImmutableList> LEGACYPATH_UPDATER =
AtomicReferenceFieldUpdater.newUpdater(SchemaPath.class, ImmutableList.class, "legacyPath");
/**
* Shared instance of the conceptual root schema node.
*/
public static final SchemaPath ROOT = new AbsoluteSchemaPath(null, null);
/**
* Shared instance of the "same" relative schema node.
*/
public static final SchemaPath SAME = new RelativeSchemaPath(null, null);
/**
* Parent path.
*/
private final SchemaPath 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;
SchemaPath(final SchemaPath 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) {
final List<QName> tmp = new ArrayList<>();
for (QName qname : getPathTowardsRoot()) {
tmp.add(qname);
}
ret = ImmutableList.copyOf(Lists.reverse(tmp));
LEGACYPATH_UPDATER.lazySet(this, ret);
}
return ret;
}
/**
* Returns the complete path to schema node.
*
* @return list of <code>QName</code> instances which represents complete
* path to schema node
*
* @deprecated Use {@link #getPathFromRoot()} instead.
*/
@Deprecated
public List<QName> getPath() {
return getLegacyPath();
}
/**
* 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 SchemaPath instance.
*/
public static SchemaPath create(final Iterable<QName> path, final boolean absolute) {
final SchemaPath 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 SchemaPath create(final boolean absolute, final QName... path) {
return create(Arrays.asList(path), absolute);
}
/**
* Create a new instance.
*
* @param parent Parent SchemaPath
* @param qname next path element
* @return A new SchemaPath instance
*/
protected abstract SchemaPath createInstance(SchemaPath 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 SchemaPath createChild(final Iterable<QName> relative) {
if (Iterables.isEmpty(relative)) {
return this;
}
SchemaPath parentPath = this;
for (QName qname : relative) {
parentPath = parentPath.createInstance(parentPath, qname);
}
return parentPath;
}
/**
* Create a child path based on concatenation of this path and a relative path.
*
* @param relative Relative SchemaPath
* @return A new child path
*/
public SchemaPath createChild(final SchemaPath relative) {
Preconditions.checkArgument(!relative.isAbsolute(), "Child creation requires relative path");
SchemaPath parentPath = this;
for (QName qname : relative.getPathFromRoot()) {
parentPath = parentPath.createInstance(parentPath, qname);
}
return parentPath;
}
/**
* 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 SchemaPath 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 SchemaPath current = SchemaPath.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 SchemaPath getParent() {
return parent;
}
/**
* Get the last component of this path.
*
* @return The last component of this path.
*/
public final QName getLastComponent() {
return qname;
}
/**
* Describes whether schema path 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 SchemaPath other = (SchemaPath) 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());
}
}