zkoss/zk

/* AbstractExecution.java

    Purpose:
        
    Description:
        
    History:
        Mon Jun  6 12:18:25     2005, Created by tomyeh

Copyright (C) 2005 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.impl;

import java.io.IOException;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.zkoss.idom.Document;
import org.zkoss.util.CollectionsX;
import org.zkoss.web.servlet.Servlets;
import org.zkoss.xel.VariableResolver;
import org.zkoss.xel.VariableResolverX;
import org.zkoss.xel.XelContext;
import org.zkoss.zk.au.AuResponse;
import org.zkoss.zk.au.http.AuRedirect;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.Desktop;
import org.zkoss.zk.ui.Execution;
import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.Page;
import org.zkoss.zk.ui.Session;
import org.zkoss.zk.ui.Sessions;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.metainfo.PageDefinition;
import org.zkoss.zk.ui.sys.DesktopCtrl;
import org.zkoss.zk.ui.sys.ExecutionCtrl;
import org.zkoss.zk.ui.sys.ExecutionInfo;
import org.zkoss.zk.ui.sys.UiEngine;
import org.zkoss.zk.ui.sys.Visualizer;
import org.zkoss.zk.ui.sys.WebAppCtrl;
import org.zkoss.zk.ui.util.Callback;

/**
 * A skeletal implementation of {@link Execution}.
 *
 * @author tomyeh
 */
public abstract class AbstractExecution implements Execution, ExecutionCtrl {
    private static final Logger _zklog = LoggerFactory.getLogger("org.zkoss.zk.log");

    private Desktop _desktop;
    private Page _curpage;
    private PageDefinition _curpgdef;

    /* A list of EventInfo within the same priority.
     */
    private final Map<Integer, List<EventInfo>> _evtInfos = new TreeMap<Integer, List<EventInfo>>(
            new Comparator<Integer>() {
                public int compare(Integer o1, Integer o2) {
                    // reverse it, returning the greater one first.
                    return o2.compareTo(o1);
                }
            });

    /** A stack of args being pushed by {@link #pushArg}. */
    private List<Map<?, ?>> _args;
    //private Event _evtInProc;
    /** Which page is being created, or null if all in update mode. */
    private final Page _creating;
    /** The sequence ID of the current request. */
    private String _reqId;
    /** A collection of the AU responses that shall be generated to client */
    private Collection<AuResponse> _resps;
    /** The information of the event being served, or null if not under event processing. */
    private ExecutionInfo _execinf;
    private List<VariableResolver> _resolvers;

    protected static final String Add_ON_ACTIVATE = "org.zkoss.zk.ui.executions.addOnActivate";
    protected static final String Add_ON_DEACTIVATE = "org.zkoss.zk.ui.executions.addOnDeactivate";

    /** Constructs an execution.
     * @param creating which page is being creating for this execution, or
     * null if none is being created.
     * {@link #isAsyncUpdate} returns based on this.
     */
    protected AbstractExecution(Desktop desktop, Page creating) {
        _desktop = desktop; //it is null if it is created by WebManager.newDesktop
        _curpage = _creating = creating;
        if (_curpage == null)
            _curpage = getPage(desktop);
    }

    private static Page getPage(Desktop desktop) {
        return desktop != null ? desktop.getFirstPage() : null;
    }

    //-- Execution --//
    public boolean isAsyncUpdate(Page page) {
        if (page != null)
            return _creating != page;
        final Visualizer uv;
        return (uv = getVisualizer()) != null && uv.isEverAsyncUpdate();
    }

    public Desktop getDesktop() {
        return _desktop;
    }

    public Session getSession() {
        return _desktop != null ? _desktop.getSession() : Sessions.getCurrent();
    }

    public void postEvent(Event evt) {
        postEvent(0, evt);
    }

    public void postEvent(int priority, Event evt) {
        if (evt == null)
            throw new IllegalArgumentException("null");

        evt = ((DesktopCtrl) _desktop).beforePostEvent(evt);
        if (evt == null)
            return; //done (ignored)

        List<EventInfo> eventInfos = _evtInfos.get(priority);
        if (eventInfos != null) {
            eventInfos.add(new EventInfo(priority, evt));
        } else {
            eventInfos = new LinkedList<EventInfo>();
            eventInfos.add(new EventInfo(priority, evt));
            _evtInfos.put(priority, eventInfos);
        }
    }

    public void postEvent(int priority, Component realTarget, Event evt) {
        postEvent(priority, realTarget != evt.getTarget() ? new ProxyEvent(realTarget, evt) : evt);
    }

    //-- ExecutionCtrl --//
    public Object getAttribute(String name, boolean recurse) {
        Object val = getAttribute(name);
        Desktop desktop;
        return val != null || !recurse || (desktop = getDesktop()) == null ? val : desktop.getAttribute(name, true);
    }

    public boolean hasAttribute(String name, boolean recurse) {
        Desktop desktop;
        return hasAttribute(name) || (recurse && (desktop = getDesktop()) != null && desktop.hasAttribute(name, true));
    }

    public Object setAttribute(String name, Object value, boolean recurse) {
        if (recurse && !hasAttribute(name)) {
            Desktop desktop = getDesktop();
            if (desktop != null) {
                if (desktop.hasAttribute(name, true))
                    return desktop.setAttribute(name, value, true);
            }
        }
        return setAttribute(name, value);
    }

    public Object removeAttribute(String name, boolean recurse) {
        if (recurse && !hasAttribute(name)) {
            Desktop desktop = getDesktop();
            if (desktop != null) {
                if (desktop.hasAttribute(name, true))
                    return desktop.removeAttribute(name, true);
            }
            return null;
        }
        return removeAttribute(name);
    }

    public final Page getCurrentPage() {
        if (_curpage == null)
            _curpage = getPage(_desktop);
        return _curpage;
    }

    public final void setCurrentPage(Page curpage) {
        if (_curpage != null && curpage != null && _curpage != curpage) {
            Desktop curdtPrev = _curpage.getDesktop(), curdt = curpage.getDesktop();
            if (curdtPrev != null && curdt != null && curdtPrev != curdt)
                throw new IllegalStateException("Change current page to another desktop? " + curpage);
        }
        _curpage = curpage;
    }

    public PageDefinition getCurrentPageDefinition() {
        return _curpgdef;
    }

    public void setCurrentPageDefinition(PageDefinition pgdef) {
        _curpgdef = pgdef;
    }

    public Event getNextEvent() {
        Event event = retrieveNextEvent();
        if (event != null) {
            return event;
        }
        // ZK-770: EventQueue has extra delay if scope is SESSION
        ((DesktopCtrl) _desktop).onPiggyback();

        return retrieveNextEvent();
    }

    private Event retrieveNextEvent() {
        if (!_evtInfos.isEmpty()) {
            Map.Entry<Integer, List<EventInfo>> me = _evtInfos.entrySet().iterator().next();
            List<EventInfo> value = me.getValue();
            EventInfo remove = value.remove(0);
            if (value.isEmpty()) {
                _evtInfos.remove(me.getKey());
            }
            return remove.event;
        }
        return null;
    }

    public boolean isActivated() {
        return getVisualizer() != null;
    }

    @SuppressWarnings("unchecked")
    public void onActivate() {
        if (_desktop != null) {
            List<Callback> callbacks = (List<Callback>) _desktop.getAttribute(Add_ON_ACTIVATE);
            if (callbacks != null) {
                for (Iterator<Callback> it = callbacks.iterator(); it.hasNext();) {
                    Callback callback = it.next();
                    callback.call(null);
                    it.remove();
                }
            }
        }
    }

    @SuppressWarnings("unchecked")
    public void onBeforeDeactivate() {
        if (_desktop != null) {
            List<Callback> callbacks = (List<Callback>) _desktop.getAttribute(Add_ON_DEACTIVATE);
            if (callbacks != null) {
                for (Iterator<Callback> it = callbacks.iterator(); it.hasNext();) {
                    Callback callback = it.next();
                    callback.call(null);
                    it.remove();
                }
            }
        }
    }

    public void onDeactivate() {
    }

    public boolean isRecovering() {
        Visualizer uv = getVisualizer();
        return uv != null && uv.isRecovering();
    }

    public Visualizer getVisualizer() {
        return _desktop != null ? ((DesktopCtrl) _desktop).getVisualizer() : null;
    }

    public String toAbsoluteURI(String uri, boolean skipInclude) {
        if (uri != null && uri.length() > 0) {
            final char cc = uri.charAt(0);
            if (cc != '/' && cc != '~' && !(skipInclude && isIncluded()) && !Servlets.isUniversalURL(uri)) {
                final String dir = getDesktop().getCurrentDirectory();
                if (dir != null)
                    return dir + uri;
            }
        }
        return uri;
        //we ignore _creating, because Servlet's include cannot handle
        //related URI correctly (even though it is by the layout servlet)
    }

    private final UiEngine getUiEngine() {
        return ((WebAppCtrl) _desktop.getWebApp()).getUiEngine();
    }

    public Component createComponents(String uri, Component parent, Map<?, ?> arg) {
        return createComponents0(uri, parent, null, null, arg);
    }

    public Component createComponents(String uri, Component parent, Component insertBefore, VariableResolver resolver) {
        return createComponents0(uri, parent, insertBefore, resolver, null);
    }

    public Component[] createComponents(String uri, Component parent, Component insertBefore, VariableResolver resolver,
            Map<?, ?> arg) {
        final Component[] cs = getUiEngine().createComponents(this, getPageDefinition(uri), getCurrentPage(), parent,
                insertBefore, resolver, arg);
        return cs.length > 0 ? cs : null;
    }

    public Component createComponents(PageDefinition pagedef, Component parent, Map<?, ?> arg) {
        return createComponents0(pagedef, parent, null, null, arg);
    }

    public Component createComponents(PageDefinition pagedef, Component parent, Component insertBefore,
            VariableResolver resolver) {
        return createComponents0(pagedef, parent, insertBefore, resolver, null);
    }

    public Component[] createComponents(String uri, Map<?, ?> arg) {
        return getUiEngine().createComponents(this, getPageDefinition(uri), null, null, null, null, arg);
    }

    public Component[] createComponents(String uri, Page page, VariableResolver resolver, Map<?, ?> arg) {
        return getUiEngine().createComponents(this, getPageDefinition(uri), page, null, null, resolver, arg);
    }

    public Component[] createComponents(PageDefinition pagedef, Map<?, ?> arg) {
        if (pagedef == null)
            throw new IllegalArgumentException("pagedef cannot be null");
        return getUiEngine().createComponents(this, pagedef, null, null, null, null, arg);
    }

    private Component createComponents0(String uri, Component parent, Component insertBefore, VariableResolver resolver,
            Map<?, ?> arg) {
        final Component[] cs = getUiEngine().createComponents(this, getPageDefinition(uri), getCurrentPage(), parent,
                insertBefore, resolver, arg);
        return cs.length > 0 ? cs[0] : null;
    }

    private Component createComponents0(PageDefinition pagedef, Component parent, Component insertBefore,
            VariableResolver resolver, Map<?, ?> arg) {
        if (pagedef == null)
            throw new IllegalArgumentException("pagedef cannot be null");
        final Component[] cs = getUiEngine().createComponents(this, pagedef, getCurrentPage(), parent, insertBefore,
                resolver, arg);
        return cs.length > 0 ? cs[0] : null;
    }

    public Component createComponentsDirectly(String content, String ext, Component parent, Map<?, ?> arg) {
        return createComponentsDirectly0(content, ext, parent, null, null, arg);
    }

    public Component createComponentsDirectly(String content, String ext, Component parent, Component insertBefore,
            VariableResolver resolver) {
        return createComponentsDirectly0(content, ext, parent, insertBefore, resolver, null);
    }

    public Component createComponentsDirectly(Document content, String ext, Component parent, Map<?, ?> arg) {
        return createComponentsDirectly0(content, ext, parent, null, null, arg);
    }

    public Component createComponentsDirectly(Document content, String ext, Component parent, Component insertBefore,
            VariableResolver resolver) {
        return createComponentsDirectly0(content, ext, parent, insertBefore, resolver, null);
    }

    public Component createComponentsDirectly(Reader reader, String ext, Component parent, Map<?, ?> arg)
            throws IOException {
        return createComponentsDirectly0(reader, ext, parent, null, null, arg);
    }

    public Component createComponentsDirectly(Reader reader, String ext, Component parent, Component insertBefore,
            VariableResolver resolver) throws IOException {
        return createComponentsDirectly0(reader, ext, parent, insertBefore, resolver, null);
    }

    public Component[] createComponentsDirectly(String content, String ext, Map<?, ?> arg) {
        return getUiEngine().createComponents(this, getPageDefinitionDirectly(content, ext), null, null, null, null,
                arg);
    }

    public Component[] createComponentsDirectly(Document content, String ext, Map<?, ?> arg) {
        return getUiEngine().createComponents(this, getPageDefinitionDirectly(content, ext), null, null, null, null,
                arg);
    }

    public Component[] createComponentsDirectly(Reader reader, String ext, Map<?, ?> arg) throws IOException {
        return getUiEngine().createComponents(this, getPageDefinitionDirectly(reader, ext), null, null, null, null,
                arg);
    }

    private Component createComponentsDirectly0(String content, String ext, Component parent, Component insertBefore,
            VariableResolver resolver, Map<?, ?> arg) {
        final Component[] cs = getUiEngine().createComponents(this, getPageDefinitionDirectly(content, ext),
                getCurrentPage(), parent, insertBefore, resolver, arg);
        return cs.length > 0 ? cs[0] : null;
    }

    private Component createComponentsDirectly0(Document content, String ext, Component parent, Component insertBefore,
            VariableResolver resolver, Map<?, ?> arg) {
        final Component[] cs = getUiEngine().createComponents(this, getPageDefinitionDirectly(content, ext),
                getCurrentPage(), parent, insertBefore, resolver, arg);
        return cs.length > 0 ? cs[0] : null;
    }

    private Component createComponentsDirectly0(Reader reader, String ext, Component parent, Component insertBefore,
            VariableResolver resolver, Map<?, ?> arg) throws IOException {
        final Component[] cs = getUiEngine().createComponents(this, getPageDefinitionDirectly(reader, ext),
                getCurrentPage(), parent, insertBefore, resolver, arg);
        return cs.length > 0 ? cs[0] : null;
    }

    public void sendRedirect(String uri) {
        getUiEngine().sendRedirect(uri, null);
    }

    public void sendRedirect(String uri, String target) {
        getUiEngine().sendRedirect(uri, target);
    }

    public void sendRedirect(String uri, boolean respRedirect) {
        if (!respRedirect) {
            sendRedirect(uri);
            return;
        } else {
            uri = uri == null ? "" : uri;
            HttpServletResponse resp = (HttpServletResponse) getNativeResponse();
            try {
                String destUrl = encodeURL(uri);
                String destUrlParam = URLEncoder.encode(destUrl, "utf-8");
                String updateURI = _desktop.getUpdateURI(
                        AuRedirect.URI_PREFIX + "?" + AuRedirect.REDIRECT_URL_PARAMETER + "=" + destUrlParam);
                updateURI = resp.encodeRedirectURL(updateURI);
                resp.setHeader("Location", updateURI);
                resp.setStatus(HttpServletResponse.SC_FOUND);
            } catch (UnsupportedEncodingException e) {
                _zklog.warn("", e);
            }
        }
    }

    public Map<?, ?> getArg() {
        if (_args != null)
            return _args.get(0);
        return Collections.emptyMap();
    }

    public void pushArg(Map<?, ?> arg) {
        if (_args == null)
            _args = new LinkedList<Map<?, ?>>();
        _args.add(0, arg);
    }

    public void popArg() {
        if (_args != null) {
            if (_args.size() == 1)
                _args = null;
            else
                _args.remove(0);
        }
    }

    public void addAuResponse(AuResponse response) {
        getUiEngine().addResponse(response);
    }

    public void addAuResponse(String key, AuResponse response) {
        getUiEngine().addResponse(key, response);
    }

    public void setDesktop(Desktop desktop) {
        if (desktop == null)
            throw new IllegalArgumentException("null");
        if (_desktop != null && _desktop != desktop)
            throw new IllegalStateException("assign diff desktop");

        _desktop = desktop;
    }

    public void setRequestId(String reqId) {
        _reqId = reqId;
    }

    public String getRequestId() {
        return _reqId;
    }

    public Collection<AuResponse> getResponses() {
        return _resps;
    }

    public void setResponses(Collection<AuResponse> responses) {
        _resps = responses;
    }

    public ExecutionInfo getExecutionInfo() {
        return _execinf;
    }

    public void setExecutionInfo(ExecutionInfo execinf) {
        _execinf = execinf;
    }

    public boolean addVariableResolver(VariableResolver resolver) {
        if (resolver == null)
            throw new IllegalArgumentException("null");

        if (_resolvers == null)
            _resolvers = new LinkedList<VariableResolver>();
        else if (_resolvers.contains(resolver))
            return false;

        _resolvers.add(0, resolver); //FILO order
        return true;
    }

    public boolean removeVariableResolver(VariableResolver resolver) {
        return _resolvers != null && _resolvers.remove(resolver);
    }

    public boolean hasVariableResolver(VariableResolver resolver) {
        return _resolvers != null && _resolvers.contains(resolver);
    }

    public boolean hasVariableResolver(Class<? extends VariableResolver> cls) {
        if (_resolvers != null)
            for (final VariableResolver resolver : _resolvers)
                if (cls.isInstance(resolver))
                    return true;
        return false;
    }

    public Object getExtraXelVariable(String name) {
        return getExtraXelVariable(null, null, name);
    }

    public Object getExtraXelVariable(XelContext ctx, Object base, Object name) {
        //Note this method searches only _resolvers
        if (_resolvers != null) {
            for (Iterator it = CollectionsX.comodifiableIterator(_resolvers); it.hasNext();) {
                final VariableResolver vr = (VariableResolver) it.next();
                final Object o = vr instanceof VariableResolverX
                        ? ((VariableResolverX) vr).resolveVariable(ctx, base, name)
                        : base == null && name != null ? vr.resolveVariable(name.toString()) : null;
                if (o != null)
                    return o;
            }
        }
        return null;
    }

    public void log(String msg) {
        if (_desktop != null)
            _desktop.getWebApp().log(msg);
        else
            _zklog.info(msg);
    }

    public void log(String msg, Throwable ex) {
        if (_desktop != null)
            _desktop.getWebApp().log(msg, ex);
        else
            _zklog.error(msg, ex);
    }

    /**
     * Adds a callback method to be executed only once after the execution
     * activated.
     * @param callback
     * @since 7.0.5
     */
    public void addOnActivate(Callback callback) {
        Execution exec = Executions.getCurrent();
        if (exec == null)
            throw new IllegalStateException("Execution cannot be null!");
        Desktop desktop = exec.getDesktop();
        if (desktop != null) {
            List<Callback> callbacks = (List<Callback>) desktop.getAttribute(Add_ON_ACTIVATE);
            if (callbacks == null) {
                callbacks = new LinkedList<Callback>();
                desktop.setAttribute(Add_ON_ACTIVATE, callbacks);
            }
            callbacks.add(callback);
        }
    }

    /**
     * Adds a callback method to be executed only once after the execution
     * deactivated.
     * @param callback
     * @since 7.0.5
     */
    public void addOnDeactivate(Callback callback) {
        Execution exec = Executions.getCurrent();
        if (exec == null)
            throw new IllegalStateException("Execution cannot be null!");
        Desktop desktop = exec.getDesktop();
        if (desktop != null) {
            List<Callback> callbacks = (List<Callback>) desktop.getAttribute(Add_ON_DEACTIVATE);
            if (callbacks == null) {
                callbacks = new LinkedList<Callback>();
                desktop.setAttribute(Add_ON_DEACTIVATE, callbacks);
            }
            callbacks.add(callback);
        }
    }

    //Object//
    public String toString() {
        return "[Exec" + System.identityHashCode(this) + ": " + _desktop + ']';
    }

    private static class EventInfo {
        private final int priority;
        private final Event event;

        private EventInfo(int priority, Event event) {
            this.priority = priority;
            this.event = event;
        }

        public String toString() {
            return "[" + this.priority + ": " + this.event.toString() + "]";
        }
    }
}