/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2015 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.collections;
/**
* URI to represent a Collection path internally in eXist
* */
public class CollectionURI {
public final static char FRAGMENT_SEPARATOR = '/';
private char[] uri = null;
private int length = 0;
private int hash; // Default to 0
public CollectionURI(String path) {
append(path);
}
public CollectionURI(CollectionURI other) {
this.uri = new char[other.uri.length];
System.arraycopy(other.uri, 0, this.uri, 0, other.length);
this.length = other.length;
this.hash = other.hash;
}
public void append(final String segment) {
int startOffset = 0;
if (segment.charAt(0) == FRAGMENT_SEPARATOR) {
startOffset = 1;
}
if(uri == null) {
uri = new char[segment.length() + 1 - startOffset];
uri[0] = FRAGMENT_SEPARATOR;
segment.getChars(startOffset, segment.length(), uri, 1);
} else {
char newURI[] = new char[length + 1 + segment.length() - startOffset];
System.arraycopy(uri, 0, newURI, 0, length);
newURI[length] = FRAGMENT_SEPARATOR;
segment.getChars(startOffset, segment.length(), newURI, length+1);
uri = newURI;
}
length += segment.length() + 1 - startOffset;
//reset the cache
hash = 0;
}
public void removeLastSegment() {
char c;
int pos = length - 1;
while ((c = uri[pos]) != FRAGMENT_SEPARATOR) {
pos--;
}
length = pos;
//reset the cache
hash = 0;
}
public String toString() {
return new String(uri, 0, length);
}
/**
* Copied from java.lang.String.hashCode();
*
* Returns a hash code for this string. The hash code for a
* <code>String</code> object is computed as
* <blockquote><pre>
* s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
* </pre></blockquote>
* using <code>int</code> arithmetic, where <code>s[i]</code> is the
* <i>i</i>th character of the string, <code>n</code> is the length of
* the string, and <code>^</code> indicates exponentiation.
* (The hash value of the empty string is zero.)
*
* @return a hash code value for this object.
*/
public int hashCode() {
int h = hash;
if (h == 0) {
int off = 0;
for (int i = 0; i < length; i++) {
h = 31*h + uri[off++];
}
hash = h;
}
return h;
}
public boolean equals(Object object) {
if (object instanceof CollectionURI) {
final CollectionURI otherCollectionURI = (CollectionURI)object;
if (this.length == otherCollectionURI.length) {
int pos = length - 1;
while (pos > -1) {
if (this.uri[pos] != otherCollectionURI.uri[pos--])
{return false;}
}
return true;
}
}
return false;
}
}