zkoss/zk

/* Path.java

    Purpose:
        
    Description:
        
    History:
        Thu Jan 19 14:07:44     2006, Created by tomyeh

Copyright (C) 2006 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
    This program is distributed under LGPL Version 2.1 in the hope that
    it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.zk.ui;

import org.zkoss.io.Files;
import org.zkoss.zk.ui.sys.ExecutionCtrl;

/**
 * A representation of a component path.
 * <p>There are three formats:
 * //page-id/comp-id/comp-id<br/>
 * /comp-id/comp-id<br/>
 * comp-id/comp-id
 *
 * <p>Alternatively, you could use {@link Component#query}
 * or {@link Component#queryAll} instead.
 *
 * @author tomyeh
 */
public class Path {
    private final String _path;

    public Path() {
        this((String) null);
    }

    public Path(String path) {
        _path = Files.normalize(path);
    }

    public Path(String parent, String child) {
        this(parent == null || parent.length() == 0 ? child
                : child == null || child.length() == 0 ? parent : parent + '/' + child);
    }

    public Path(Path parent, String child) {
        this(parent != null ? parent.getPath() : null, child);
    }

    /** Returns the path of the specified component. */
    public Path(Component comp) {
        this(getPath(comp));
    }

    /** Returns the path (after normalized).
     */
    public String getPath() {
        return _path;
    }

    /** Returns the path of the specified component.
     */
    public static final String getPath(Component comp) {
        final StringBuffer sb = new StringBuffer(64);
        for (;;) {
            if (sb.length() > 0)
                sb.insert(0, '/');
            final String compId = comp.getId();
            if (compId.length() == 0)
                throw new UiException("ID required: " + comp);
            sb.insert(0, compId);
            IdSpace is = comp.getSpaceOwner();
            if (is instanceof Page)
                break; //done

            if (is == comp) {
                final Component p = ((Component) is).getParent();
                if (p == null)
                    break; //topmost
                is = p.getSpaceOwner();
                if (is instanceof Page)
                    break; //done
            }
            comp = (Component) is;
        }
        sb.insert(0, '/');
        return sb.toString();
    }

    /** Returns the component with this path, or null if no such component.
     */
    public Component getComponent() {
        return getComponent0(null, _path);
    }

    /** Returns the component of the specified path, or null if no such component.
     */
    public static final Component getComponent(String path) {
        return getComponent0(null, Files.normalize(path));
    }

    /** Returns the component of the specified path which is related
     * to the specified ID space, or null if no such component.
     *
     * @param is the current ID space. It is required only if path is related
     * (in other words, not starting with / or //).
     */
    public static final Component getComponent(IdSpace is, String path) {
        return getComponent0(is, Files.normalize(path));
    }

    private static final Component getComponent0(IdSpace is, String path) {
        Component found = null;
        for (int j = 0, k;; j = k + 1) {
            k = path.indexOf('/', j);

            if (k == 0) { //starts with /
                final Execution exec = Executions.getCurrent();
                final Desktop desktop = exec.getDesktop();
                Page page = ((ExecutionCtrl) exec).getCurrentPage();
                if (page == null) {
                    page = desktop.getFirstPage();
                    if (page == null)
                        return null;
                }

                if (path.length() == 1) // "/" only
                    return page.getFirstRoot(); //the first root assumed

                if (path.charAt(1) == '/') { //starts with //
                    k = path.indexOf('/', 2);
                    if (k < 0)
                        return null; //page is not component

                    final String nm = path.substring(2, k);
                    is = desktop.getPageIfAny(nm);
                    if (is == null)
                        return null; //no such page
                } else {
                    is = page;
                }
                continue;
            }

            final String nm = k >= 0 ? path.substring(j, k) : path.substring(j);
            if ("..".equals(nm)) {
                if (!(is instanceof Component))
                    return null;

                final Component c = (Component) is;
                final Component p = c.getParent();
                is = p != null ? p.getSpaceOwner() : c.getPage();
                if (k < 0) {
                    return (is instanceof Component) ? (Component) is : null;
                }
                continue;
            }
            if (is == null)
                return null;

            final Component c = is.getFellowIfAny(nm);
            if (k < 0 || c == null)
                return c;

            if (!(c instanceof IdSpace))
                return null;
            is = (IdSpace) c;
        }
    }

    //--Object--//
    public boolean equals(Object o) {
        if (this == o)
            return true;
        return o instanceof Path && ((Path) o)._path.equals(_path);
    }

    public int hashCode() {
        return _path.hashCode();
    }

    public String toString() {
        return _path;
    }
}