/*
* 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.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
import net.jcip.annotations.Immutable;
import net.jcip.annotations.NotThreadSafe;
import org.jboss.dna.common.CommonI18n;
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;
/**
* An abstract foundation for different {@link Path} implementations. This class does not manage any of the {@link Path}'s state,
* but it does provide implementations for most of the methods based upon a few abstract methods. For example, any implementaton
* that requires the {@link Path.Segment path's segments} are written to use the {@link #iterator()}, since that is likely more
* efficient for the majority of implementations.
*/
@Immutable
public abstract class AbstractPath implements Path {
/**
* The initial serializable version. Version {@value}
*/
private static final long serialVersionUID = 1L;
public static final Path SELF_PATH = new BasicPath(Collections.singletonList(Path.SELF_SEGMENT), false);
protected static Iterator<Path.Segment> EMPTY_PATH_ITERATOR = new Iterator<Segment>() {
/**
* {@inheritDoc}
*
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() {
return false;
}
/**
* {@inheritDoc}
*
* @see java.util.Iterator#next()
*/
public Segment next() {
throw new NoSuchElementException();
}
/**
* {@inheritDoc}
*
* @see java.util.Iterator#remove()
*/
public void remove() {
throw new UnsupportedOperationException();
}
};
@NotThreadSafe
protected static class SingleIterator<T> implements Iterator<T> {
private T value;
protected SingleIterator( T value ) {
this.value = value;
}
/**
* {@inheritDoc}
*
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() {
return value != null;
}
/**
* {@inheritDoc}
*
* @see java.util.Iterator#next()
*/
public T next() {
if (value == null) throw new NoSuchElementException();
T next = value;
value = null;
return next;
}
/**
* {@inheritDoc}
*
* @see java.util.Iterator#remove()
*/
public void remove() {
throw new UnsupportedOperationException();
}
}
private transient int hc = 0;
protected boolean isNormalized( List<Segment> segments ) {
boolean nonParentReference = false;
boolean first = isAbsolute(); // only care about first one when it's absolute
for (Segment segment : segments) {
if (segment.isSelfReference()) return false;
if (segment.isParentReference()) {
if (nonParentReference || first) return false;
} else {
nonParentReference = true;
}
first = false;
}
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getCanonicalPath()
*/
public Path getCanonicalPath() {
if (!this.isAbsolute()) {
String msg = GraphI18n.pathIsNotAbsolute.text(this);
throw new InvalidPathException(msg);
}
if (this.isNormalized()) return this;
return this.getNormalizedPath();
}
/**
* {@inheritDoc}
*/
public Path getCommonAncestor( Path that ) {
CheckArg.isNotNull(that, "that");
if (that.isRoot()) return that;
Path normalizedPath = this.getNormalizedPath();
int lastIndex = 0;
Iterator<Segment> thisIter = normalizedPath.iterator();
Iterator<Segment> thatIter = that.getNormalizedPath().iterator();
while (thisIter.hasNext() && thatIter.hasNext()) {
Segment thisSeg = thisIter.next();
Segment thatSeg = thatIter.next();
if (thisSeg.equals(thatSeg)) {
++lastIndex;
} else {
break;
}
}
if (lastIndex == 0) return RootPath.INSTANCE;
return normalizedPath.subpath(0, lastIndex);
}
/**
* {@inheritDoc}
*/
public Path.Segment getLastSegment() {
return this.getSegmentsList().get(size() - 1);
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#endsWith(org.jboss.dna.graph.property.Name)
*/
public boolean endsWith( Name nameOfLastSegment ) {
Segment segment = getLastSegment();
return segment != null && segment.getName().equals(nameOfLastSegment) && !segment.hasIndex();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#endsWith(org.jboss.dna.graph.property.Name, int)
*/
public boolean endsWith( Name nameOfLastSegment,
int snsIndex ) {
Segment segment = getLastSegment();
return segment != null && segment.getName().equals(nameOfLastSegment) && segment.getIndex() == snsIndex;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#getParent()
*/
public Path getParent() {
return getAncestor(1);
}
/**
* {@inheritDoc}
*/
public Segment getSegment( int index ) {
CheckArg.isNonNegative(index, "index");
return this.getSegmentsList().get(index);
}
/**
* {@inheritDoc}
*/
public Segment[] getSegmentsArray() {
// By default, make a new array every time since arrays are mutable, and use the iterator
// since that is probably more efficient than creating a list ...
Segment[] result = new Path.Segment[size()];
int i = 0;
for (Segment segment : this) {
result[i] = segment;
++i;
}
return result;
}
/**
* {@inheritDoc}
*/
public Path getNormalizedPath() {
if (this.isNormalized()) return this;
LinkedList<Segment> newSegments = new LinkedList<Segment>();
for (Segment segment : this) {
if (segment.isSelfReference()) continue;
if (segment.isParentReference()) {
if (newSegments.isEmpty()) {
if (this.isAbsolute()) {
throw new InvalidPathException(CommonI18n.pathCannotBeNormalized.text(this));
}
} else if (!newSegments.getLast().isParentReference()) {
newSegments.removeLast();
continue;
}
}
newSegments.add(segment);
}
if (newSegments.isEmpty()) {
if (this.isAbsolute()) return RootPath.INSTANCE;
// Otherwise relative and it had contained nothing but self references ...
return SELF_PATH;
}
return new BasicPath(newSegments, this.isAbsolute());
}
/**
* {@inheritDoc}
*/
public String getString() {
return doGetString(null, null, null);
}
/**
* {@inheritDoc}
*/
public String getString( TextEncoder encoder ) {
return doGetString(null, encoder, null);
}
/**
* {@inheritDoc}
*/
public String getString( NamespaceRegistry namespaceRegistry ) {
CheckArg.isNotNull(namespaceRegistry, "namespaceRegistry");
return doGetString(namespaceRegistry, null, null);
}
/**
* {@inheritDoc}
*/
public String getString( NamespaceRegistry namespaceRegistry,
TextEncoder encoder ) {
CheckArg.isNotNull(namespaceRegistry, "namespaceRegistry");
return doGetString(namespaceRegistry, encoder, null);
}
/**
* {@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)
*/
public String getString( NamespaceRegistry namespaceRegistry,
TextEncoder encoder,
TextEncoder delimiterEncoder ) {
return doGetString(namespaceRegistry, encoder, delimiterEncoder);
}
/**
* Method that creates the string representation. This method works two different ways depending upon whether the namespace
* registry is provided.
*
* @param namespaceRegistry
* @param encoder
* @param delimiterEncoder
* @return this path as a string
*/
protected String doGetString( NamespaceRegistry namespaceRegistry,
TextEncoder encoder,
TextEncoder delimiterEncoder ) {
if (encoder == null) encoder = DEFAULT_ENCODER;
final String delimiter = delimiterEncoder != null ? delimiterEncoder.encode(DELIMITER_STR) : DELIMITER_STR;
// Since the segments are immutable, this code need not be synchronized because concurrent threads
// may just compute the same value (with no harm done)
StringBuilder sb = new StringBuilder();
if (this.isAbsolute()) sb.append(delimiter);
boolean first = true;
for (Segment segment : this) {
if (first) {
first = false;
} else {
sb.append(delimiter);
}
assert segment != null;
sb.append(segment.getString(namespaceRegistry, encoder, delimiterEncoder));
}
String result = sb.toString();
// Save the result to the internal string if this the default encoder is used.
// This is not synchronized, but it's okay
return result;
}
/**
* {@inheritDoc}
*/
public boolean hasSameAncestor( Path that ) {
CheckArg.isNotNull(that, "that");
if (that.size() != this.size()) return false;
if (this.size() == 1) return true; // both nodes are just under the root
for (int i = this.size() - 2; i >= 0; --i) {
Path.Segment thisSegment = this.getSegment(i);
Path.Segment thatSegment = that.getSegment(i);
if (!thisSegment.equals(thatSegment)) return false;
}
return true;
}
/**
* {@inheritDoc}
*/
public boolean isAncestorOf( Path decendant ) {
CheckArg.isNotNull(decendant, "that");
if (this == decendant) return false;
if (this.size() >= decendant.size()) return false;
Iterator<Path.Segment> thisIter = this.iterator();
Iterator<Path.Segment> thatIter = decendant.iterator();
while (thisIter.hasNext()) {
Path.Segment thisSeg = thisIter.next();
Path.Segment thatSeg = thatIter.next();
if (!thisSeg.equals(thatSeg)) return false;
}
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAtOrBelow(org.jboss.dna.graph.property.Path)
*/
public boolean isAtOrBelow( Path other ) {
CheckArg.isNotNull(other, "other");
if (this == other) return true;
if (other.isRoot()) return true;
if (other.size() > this.size()) return false;
Iterator<Segment> thisIter = iterator();
Iterator<Segment> thatIter = other.iterator();
while (thisIter.hasNext() && thatIter.hasNext()) {
if (!thisIter.next().equals(thatIter.next())) return false;
}
if (thatIter.hasNext()) return false; // The other still has segments, but this doesn't
return true;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#isAtOrAbove(org.jboss.dna.graph.property.Path)
*/
public boolean isAtOrAbove( Path other ) {
CheckArg.isNotNull(other, "other");
if (this == other) return true;
if (this.size() > other.size()) return false;
Iterator<Segment> thisIter = iterator();
Iterator<Segment> thatIter = other.iterator();
while (thisIter.hasNext() && thatIter.hasNext()) {
if (!thisIter.next().equals(thatIter.next())) return false;
}
if (thisIter.hasNext()) return false; // This still has segments, but other doesn't
return true;
}
/**
* {@inheritDoc}
*/
public boolean isDecendantOf( Path ancestor ) {
CheckArg.isNotNull(ancestor, "ancestor");
return ancestor.isAncestorOf(this);
}
/**
* {@inheritDoc}
*/
public boolean isSameAs( Path other ) {
return other != null && this.compareTo(other) == 0;
}
/**
* {@inheritDoc}
*/
public Iterator<Segment> iterator() {
return getSegmentsList().iterator();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#pathsFromRoot()
*/
public Iterator<Path> pathsFromRoot() {
LinkedList<Path> paths = new LinkedList<Path>();
Path path = this;
while (path != null) {
paths.addFirst(path);
if (path.isRoot()) break;
path = path.getParent();
}
return paths.iterator();
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.property.Path#relativeToRoot()
*/
public Path relativeToRoot() {
return new BasicPath(getSegmentsList(), false);
}
/**
* {@inheritDoc}
*/
public Path relativeTo( Path startingPath ) {
CheckArg.isNotNull(startingPath, "to");
if (!this.isAbsolute()) {
String msg = GraphI18n.pathIsNotAbsolute.text(this);
throw new InvalidPathException(msg);
}
if (startingPath.isRoot()) {
// We just want a relative path containing the same segments ...
return relativeToRoot();
}
if (!startingPath.isAbsolute()) {
String msg = GraphI18n.pathIsNotAbsolute.text(startingPath);
throw new InvalidPathException(msg);
}
// Count the number of segments up to the common ancestor (relative path is what remains) ...
int lengthOfCommonAncestor = 0;
Iterator<Segment> thisIter = this.getNormalizedPath().iterator();
Iterator<Segment> toIter = startingPath.getNormalizedPath().iterator();
while (thisIter.hasNext() && toIter.hasNext()) {
Segment thisSeg = thisIter.next();
Segment toSeg = toIter.next();
if (thisSeg.equals(toSeg)) {
++lengthOfCommonAncestor;
} else {
break;
}
}
// Create the relative path, starting with parent references to the common ancestor ...
int numberOfParentReferences = startingPath.size() - lengthOfCommonAncestor;
List<Segment> relativeSegments = new ArrayList<Segment>();
for (int i = 0; i != numberOfParentReferences; ++i) {
relativeSegments.add(Path.PARENT_SEGMENT);
}
// Add the segments of this path from the common ancestor ...
for (int i = lengthOfCommonAncestor; i < this.size(); ++i) {
relativeSegments.add(getSegment(i));
}
if (relativeSegments.isEmpty()) {
relativeSegments.add(Path.SELF_SEGMENT);
}
return new BasicPath(relativeSegments, false);
}
/**
* {@inheritDoc}
*/
public Path resolve( Path relativePath ) {
CheckArg.isNotNull(relativePath, "relative path");
if (!this.isAbsolute()) {
String msg = GraphI18n.pathIsNotAbsolute.text(this);
throw new InvalidPathException(msg);
}
if (relativePath.isAbsolute()) {
String msg = GraphI18n.pathIsNotRelative.text(relativePath);
throw new InvalidPathException(msg);
}
// If the relative path is the self or parent reference ...
relativePath = relativePath.getNormalizedPath();
if (relativePath.size() == 1) {
Segment onlySegment = relativePath.getSegment(0);
if (onlySegment.isSelfReference()) return this;
if (onlySegment.isParentReference()) return this.getParent();
}
List<Segment> segments = new ArrayList<Segment>(this.size() + relativePath.size());
for (Segment segment : this) {
segments.add(segment);
}
for (Segment segment : relativePath) {
segments.add(segment);
}
return new BasicPath(segments, true).getNormalizedPath();
}
/**
* {@inheritDoc}
*/
public Path resolveAgainst( Path absolutePath ) {
CheckArg.isNotNull(absolutePath, "absolute path");
return absolutePath.resolve(this);
}
/**
* {@inheritDoc}
*/
public Path subpath( int beginIndex ) {
return subpath(beginIndex, size());
}
/**
* {@inheritDoc}
*/
public Path subpath( int beginIndex,
int endIndex ) {
CheckArg.isNonNegative(beginIndex, "beginIndex");
CheckArg.isNonNegative(endIndex, "endIndex");
int size = size();
if (beginIndex == 0) {
if (endIndex == 0) return RootPath.INSTANCE;
if (endIndex == size) return this;
}
if (beginIndex >= size) {
throw new IndexOutOfBoundsException(
GraphI18n.unableToCreateSubpathBeginIndexGreaterThanOrEqualToSize.text(beginIndex,
size));
}
if (beginIndex > endIndex) {
throw new IndexOutOfBoundsException(
GraphI18n.unableToCreateSubpathBeginIndexGreaterThanOrEqualToEndingIndex.text(beginIndex,
endIndex));
}
// This reuses the same list, so it's pretty efficient ...
return new BasicPath(createSegmentsSubList(beginIndex, endIndex), this.isAbsolute());
}
protected List<Segment> createSegmentsSubList( int validBeginIndex,
int validEndIndex ) {
return this.getSegmentsList().subList(validBeginIndex, validEndIndex);
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
if (hc == 0) {
int hashCode = 1;
for (Segment segment : this) {
hashCode = 31 * hashCode + segment.hashCode();
}
hc = hashCode;
}
return hc;
}
/**
* Method used by {@link AbstractPath#equals(Object)} implementation to quickly get an Iterator over the segments in the
* parent.
*
* @return the iterator over the segments; never null, but may not have any elements
*/
protected abstract Iterator<Segment> getSegmentsOfParent();
/**
* {@inheritDoc}
*/
@Override
public boolean equals( Object obj ) {
if (obj == this) return true;
if (obj instanceof Path) {
Path that = (Path)obj;
// First check whether the paths are roots ...
if (this.isRoot()) return that.isRoot();
else if (that.isRoot()) return false;
// Now check the hash code and size ...
if (this.hashCode() != that.hashCode()) return false;
if (this.size() != that.size()) return false;
// Check the last segments, since these will often differ anyway ...
if (!this.getLastSegment().equals(that.getLastSegment())) return false;
if (this.size() == 1) return true;
// Check the rest of the names ...
Iterator<Segment> thisIter = that instanceof AbstractPath ? this.getSegmentsOfParent() : this.iterator();
Iterator<Segment> thatIter = that instanceof AbstractPath ? ((AbstractPath)that).getSegmentsOfParent() : that.iterator();
while (thisIter.hasNext()) {
Segment thisSegment = thisIter.next();
Segment thatSegment = thatIter.next();
if (!thisSegment.equals(thatSegment)) return false;
}
return true;
}
return false;
}
/**
* {@inheritDoc}
*/
public int compareTo( Path that ) {
if (this == that) return 0;
Iterator<Segment> thisIter = getSegmentsList().iterator();
Iterator<Segment> thatIter = that.iterator();
while (thisIter.hasNext() && thatIter.hasNext()) {
Segment thisSegment = thisIter.next();
Segment thatSegment = thatIter.next();
int diff = thisSegment.compareTo(thatSegment);
if (diff != 0) return diff;
}
if (thisIter.hasNext()) return 1;
if (thatIter.hasNext()) return -1;
return 0;
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return getString(Path.NO_OP_ENCODER);
}
}