XPathUtils.java

package gr.ntua.ivml.athena.xml.util;

public class XPathUtils {
	public static String difference(String xpath1, String xpath2) {
        String[] paths1 = split(xpath1);
        String[] paths2 = split(xpath2);
        int length = Math.min(paths1.length, paths2.length);
        int index = 0;
        while (index < length && paths1[index].equals(paths2[index])) {
            index++;
        }
        StringBuffer b = new StringBuffer();
        for (int i = 0; i < index; i++) {
            b.append(paths1[i]);
        }
        while (index < paths1.length) {
            b.append(paths1[index++]);
            b.append('/');
        }
        return b.toString();
    }
    
    public static String[] split(String xpath) {
        String[] paths = xpath.split("/");
        if (paths.length == 0) {
            paths = new String[1];
            paths[0] = "";
        }
        return paths;
    }
    
    public static int levelChange(String xpath1, String xpath2) {
        String[] paths1 = split(xpath1);
        String[] paths2 = split(xpath2);
        int length = Math.min(paths1.length, paths2.length);
        int index = 0;
        while (index < length && paths1[index].equals(paths2[index])) {
            index++;
        }
        return index;
    }
    
    public static String getLevel(String xpath, int level) {
        String[] paths = split(xpath);
        StringBuffer b = new StringBuffer();
        for (int i = 0; i < level; i++) {
            b.append(paths[i]);
            b.append(' '); // compensates the slash
        }
        b.append(paths[level]);
        b.append('/');
        return b.toString();
    }
    
    public static int getDepth(String value) {
        int len = value.length();
        int levels = 0;
        char[] chars = new char[len];
        value.getChars(0,len,chars,0);
        for (int i = 0; i < len; i++) {
            if (chars[i] == '/' && (i+1 < len) && chars[i+1] != '/') {
                levels++;
            }
        }
        return levels;
    }
    
    public static String getNamespacePrefix(String qname) {
        int i = qname.indexOf(':');
        return (i == -1) ? "" : qname.substring(0,i);
    }
}