/*
* 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.data.impl.leafref;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import java.util.Arrays;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.opendaylight.yangtools.concepts.Immutable;
public abstract class LeafRefPath implements Immutable {
/**
* An absolute LeafRefPath.
*/
private static final class AbsoluteLeafRefPath extends LeafRefPath {
private AbsoluteLeafRefPath(final LeafRefPath parent,
final QNameWithPredicate qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return true;
}
@Override
protected LeafRefPath createInstance(final LeafRefPath parent,
final QNameWithPredicate qname) {
return new AbsoluteLeafRefPath(parent, qname);
}
}
/**
* A relative LeafRefPath.
*/
private static final class RelativeLeafRefPath extends LeafRefPath {
private RelativeLeafRefPath(final LeafRefPath parent,
final QNameWithPredicate qname) {
super(parent, qname);
}
@Override
public boolean isAbsolute() {
return false;
}
@Override
protected LeafRefPath createInstance(final LeafRefPath parent,
final QNameWithPredicate qname) {
return new RelativeLeafRefPath(parent, qname);
}
}
@SuppressWarnings("rawtypes")
private static final AtomicReferenceFieldUpdater<LeafRefPath, ImmutableList> LEGACYPATH_UPDATER = AtomicReferenceFieldUpdater
.newUpdater(LeafRefPath.class, ImmutableList.class, "legacyPath");
/**
* Shared instance of the conceptual root schema node.
*/
public static final LeafRefPath ROOT = new AbsoluteLeafRefPath(null, null);
/**
* Shared instance of the "same" relative schema node.
*/
public static final LeafRefPath SAME = new RelativeLeafRefPath(null, null);
/**
* Parent path.
*/
private final LeafRefPath parent;
/**
* This component.
*/
private final QNameWithPredicate 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<QNameWithPredicate> legacyPath;
private ImmutableList<QNameWithPredicate> getLegacyPath() {
ImmutableList<QNameWithPredicate> ret = legacyPath;
if (ret == null) {
ret = ImmutableList.copyOf(getPathTowardsRoot()).reverse();
LEGACYPATH_UPDATER.lazySet(this, ret);
}
return ret;
}
protected LeafRefPath(final LeafRefPath parent, final QNameWithPredicate qname) {
this.parent = parent;
this.qname = qname;
int h = Objects.hashCode(parent);
if (qname != null) {
h = h * 31 + qname.hashCode();
}
hash = h;
}
/**
* Constructs new instance of this class with the concrete path.
*
* @param path
* list of QNameWithPredicate instances which specifies exact
* path to the module node
* @param absolute
* boolean value which specifies if the path is absolute or
* relative
*
* @return A LeafRefPath instance.
*/
public static LeafRefPath create(final Iterable<QNameWithPredicate> path,
final boolean absolute) {
final LeafRefPath 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 QNameWithPredicate instances which specifies exact
* path to the module node
*
* @return A LeafRefPath instance.
*/
public static LeafRefPath create(final boolean absolute,
final QNameWithPredicate... path) {
return create(Arrays.asList(path), absolute);
}
/**
* Create a new instance.
*
* @param parent
* Parent LeafRefPath
* @param qname
* next path element
* @return A new LeafRefPath instance
*/
protected abstract LeafRefPath createInstance(LeafRefPath parent,
QNameWithPredicate 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 LeafRefPath createChild(final Iterable<QNameWithPredicate> relative) {
if (Iterables.isEmpty(relative)) {
return this;
}
LeafRefPath parent = this;
for (QNameWithPredicate qname : relative) {
parent = parent.createInstance(parent, qname);
}
return parent;
}
/**
* Create a child path based on concatenation of this path and a relative
* path.
*
* @param relative
* Relative LeafRefPath
* @return A new child path
*/
public LeafRefPath createChild(final LeafRefPath relative) {
Preconditions.checkArgument(!relative.isAbsolute(), "Child creation requires relative path");
LeafRefPath parent = this;
for (QNameWithPredicate qname : relative.getPathFromRoot()) {
parent = parent.createInstance(parent, qname);
}
return parent;
}
/**
* Create a child path based on concatenation of this path and additional
* path elements.
*
* @param elements
* Relative LeafRefPath elements
* @return A new child path
*/
public LeafRefPath createChild(final QNameWithPredicate... 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 LeafRefPaths) 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<QNameWithPredicate> 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 LeafRefPaths).
*
* @return list of <code>qname</code> instances which represents path from
* the schema node towards the root.
*/
public Iterable<QNameWithPredicate> getPathTowardsRoot() {
return () -> new Iterator<QNameWithPredicate>() {
private LeafRefPath current = LeafRefPath.this;
@Override
public boolean hasNext() {
return current.parent != null;
}
@Override
public QNameWithPredicate next() {
if (current.parent == null) {
throw new NoSuchElementException("No more elements available");
}
final QNameWithPredicate ret = current.qname;
current = current.parent;
return ret;
}
@Override
public void remove() {
throw new UnsupportedOperationException("Component removal not supported");
}
};
}
/**
* Returns the immediate parent LeafRefPath.
*
* @return Parent path, null if this LeafRefPath is already toplevel.
*/
public LeafRefPath getParent() {
return parent;
}
/**
* Get the last component of this path.
*
* @return The last component of this path.
*/
public final QNameWithPredicate 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 LeafRefPath other = (LeafRefPath) obj;
return Objects.equals(qname, other.qname) && Objects.equals(parent, other.parent);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
Iterable<QNameWithPredicate> pathFromRoot = this.getPathFromRoot();
sb.append(isAbsolute() ? "Absolute path:" : "Relative path:");
for (QNameWithPredicate qName : pathFromRoot) {
sb.append('/').append(qName);
}
return sb.toString();
}
// @Override
// public final String toString() {
// return addToStringAttributes(Objects.toStringHelper(this)).toString();
// }
//
// protected ToStringHelper addToStringAttributes(final ToStringHelper
// toStringHelper) {
// return toStringHelper.add("path", getPathFromRoot());
// }
}