/*
* JBoss DNA (http://www.jboss.org/dna)
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
* See the AUTHORS.txt file in the distribution for a full listing of
* individual contributors.
*
* JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
* is licensed to you under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* JBoss DNA is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.dna.graph.property.basic;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import net.jcip.annotations.Immutable;
import org.jboss.dna.common.text.Inflector;
import org.jboss.dna.common.text.TextEncoder;
import org.jboss.dna.common.util.CheckArg;
import org.jboss.dna.graph.GraphI18n;
import org.jboss.dna.graph.property.InvalidPathException;
import org.jboss.dna.graph.property.Name;
import org.jboss.dna.graph.property.NamespaceRegistry;
import org.jboss.dna.graph.property.Path;
/**
* Optimized implementation of {@link Path} that serves as the root path.
*/
@Immutable
public class RootPath extends AbstractPath {
/**
* The serializable version. Version {@value}
*/
private static final long serialVersionUID = 1L;
public static final Path INSTANCE = new RootPath();
private static final Path.Segment[] EMPTY_SEGMENT_ARRAY = new Path.Segment[] {};
private static final List<Path.Segment> EMPTY_SEGMENT_LIST = Collections.emptyList();
private RootPath() {
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getAncestor(int)
*/
public Path getAncestor( int degree ) {
CheckArg.isNonNegative(degree, "degree");
if (degree == 0) {
return this;
}
String msg = GraphI18n.pathAncestorDegreeIsInvalid.text(this.getString(), Inflector.getInstance().ordinalize(degree));
throw new InvalidPathException(msg);
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.basic.AbstractPath#getSegmentsOfParent()
*/
@Override
protected Iterator<Segment> getSegmentsOfParent() {
return EMPTY_PATH_ITERATOR;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getCanonicalPath()
*/
@Override
public Path getCanonicalPath() {
return this;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getCommonAncestor(org.jboss.dna.graph.property.Path)
*/
@Override
public Path getCommonAncestor( Path that ) {
CheckArg.isNotNull(that, "that");
return this;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getLastSegment()
*/
@Override
public Segment getLastSegment() {
return null;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.basic.AbstractPath#endsWith(org.jboss.dna.graph.property.Name)
*/
@Override
public boolean endsWith( Name nameOfLastSegment ) {
return false;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.basic.AbstractPath#endsWith(org.jboss.dna.graph.property.Name, int)
*/
@Override
public boolean endsWith( Name nameOfLastSegment,
int snsIndex ) {
return false;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getNormalizedPath()
*/
@Override
public Path getNormalizedPath() {
return this;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.basic.AbstractPath#relativeToRoot()
*/
@Override
public Path relativeToRoot() {
return BasicPath.SELF_PATH;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.basic.AbstractPath#resolve(org.jboss.dna.graph.property.Path)
*/
@Override
public Path resolve( Path relativePath ) {
CheckArg.isNotNull(relativePath, "relative path");
if (relativePath.isAbsolute()) {
String msg = GraphI18n.pathIsNotRelative.text(relativePath);
throw new InvalidPathException(msg);
}
// Make an absolute path out of the supplied relative path ...
return new BasicPath(relativePath.getSegmentsList(), true).getNormalizedPath();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getParent()
*/
@Override
public Path getParent() {
return null;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getSegment(int)
*/
@Override
public Segment getSegment( int index ) {
CheckArg.isNonNegative(index, "index");
EMPTY_SEGMENT_LIST.get(index); // throws IndexOutOfBoundsException
return null;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getSegmentsArray()
*/
@Override
public Segment[] getSegmentsArray() {
// Can return the same array every time, since it's empty ...
return EMPTY_SEGMENT_ARRAY;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getSegmentsList()
*/
public List<Segment> getSegmentsList() {
return EMPTY_SEGMENT_LIST;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getString()
*/
@Override
public String getString() {
return Path.DELIMITER_STR;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getString(org.jboss.dna.common.text.TextEncoder)
*/
@Override
public String getString( TextEncoder encoder ) {
return Path.DELIMITER_STR;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getString(org.jboss.dna.graph.property.NamespaceRegistry)
*/
@Override
public String getString( NamespaceRegistry namespaceRegistry ) {
CheckArg.isNotNull(namespaceRegistry, "namespaceRegistry");
return Path.DELIMITER_STR;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getString(org.jboss.dna.graph.property.NamespaceRegistry,
* org.jboss.dna.common.text.TextEncoder)
*/
@Override
public String getString( NamespaceRegistry namespaceRegistry,
TextEncoder encoder ) {
CheckArg.isNotNull(namespaceRegistry, "namespaceRegistry");
return Path.DELIMITER_STR;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getString(org.jboss.dna.graph.property.NamespaceRegistry,
* org.jboss.dna.common.text.TextEncoder, org.jboss.dna.common.text.TextEncoder)
*/
@Override
public String getString( NamespaceRegistry namespaceRegistry,
TextEncoder encoder,
TextEncoder delimiterEncoder ) {
return (delimiterEncoder == null) ? DELIMITER_STR : delimiterEncoder.encode(DELIMITER_STR);
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#hasSameAncestor(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean hasSameAncestor( Path that ) {
CheckArg.isNotNull(that, "that");
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAbsolute()
*/
public boolean isAbsolute() {
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAncestorOf(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean isAncestorOf( Path decendant ) {
CheckArg.isNotNull(decendant, "decendant");
return !decendant.isRoot();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAtOrAbove(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean isAtOrAbove( Path other ) {
CheckArg.isNotNull(other, "other");
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAtOrBelow(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean isAtOrBelow( Path other ) {
CheckArg.isNotNull(other, "other");
return other.isRoot();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isDecendantOf(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean isDecendantOf( Path ancestor ) {
CheckArg.isNotNull(ancestor, "ancestor");
return false;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isNormalized()
*/
public boolean isNormalized() {
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isRoot()
*/
public boolean isRoot() {
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isSameAs(org.jboss.dna.graph.property.Path)
*/
@Override
public boolean isSameAs( Path other ) {
CheckArg.isNotNull(other, "other");
return other.isRoot();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#iterator()
*/
@Override
public Iterator<Segment> iterator() {
return EMPTY_SEGMENT_LIST.iterator();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#pathsFromRoot()
*/
@Override
public Iterator<Path> pathsFromRoot() {
return new SingleIterator<Path>(this);
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#size()
*/
public int size() {
return 0;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#subpath(int)
*/
@Override
public Path subpath( int beginIndex ) {
CheckArg.isNonNegative(beginIndex, "beginIndex");
if (beginIndex == 0) return this;
EMPTY_SEGMENT_LIST.get(1); // throws IndexOutOfBoundsException
return null;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#subpath(int, int)
*/
@Override
public Path subpath( int beginIndex,
int endIndex ) {
CheckArg.isNonNegative(beginIndex, "beginIndex");
CheckArg.isNonNegative(endIndex, "endIndex");
if (endIndex >= 1) {
EMPTY_SEGMENT_LIST.get(endIndex); // throws IndexOutOfBoundsException
}
return this;
}
/**
* {@inheritDoc}
*
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
@Override
public int compareTo( Path other ) {
return other.isRoot() ? 0 : -1;
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( Object obj ) {
if (obj == this) return true;
if (obj instanceof Path) {
Path that = (Path)obj;
return that.isRoot();
}
return false;
}
}