zkoss/zk

/* BindExpressionBuilder.java

    Purpose:
        
    Description:
        
    History:
        Aug 15, 2011 11:04:37 AM, Created by henrichen

Copyright (C) 2011 Potix Corporation. All Rights Reserved.
*/

package org.zkoss.bind.xel.zel;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

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

import org.zkoss.bind.BindContext;
import org.zkoss.bind.Binder;
import org.zkoss.bind.Form;
import org.zkoss.bind.FormLegacy;
import org.zkoss.bind.FormLegacyExt;
import org.zkoss.bind.impl.BinderImpl;
import org.zkoss.bind.impl.LoadFormBindingImpl;
import org.zkoss.bind.sys.BinderCtrl;
import org.zkoss.bind.sys.Binding;
import org.zkoss.bind.sys.LoadChildrenBinding;
import org.zkoss.bind.sys.LoadPropertyBinding;
import org.zkoss.bind.sys.ReferenceBinding;
import org.zkoss.bind.sys.SavePropertyBinding;
import org.zkoss.bind.sys.tracker.Tracker;
import org.zkoss.zel.ELContext;
import org.zkoss.zel.ELException;
import org.zkoss.zel.impl.lang.ExpressionBuilder;
import org.zkoss.zel.impl.parser.AstIdentifier;
import org.zkoss.zel.impl.parser.AstValue;
import org.zkoss.zel.impl.parser.Node;
import org.zkoss.zk.ui.Component;

/**
 * Handle value dot series script for Binding.
 * @author henrichen
 * @since 6.0.0
 */
public class BindExpressionBuilder extends ExpressionBuilder {

    private static final Logger _log = LoggerFactory.getLogger(BindExpressionBuilder.class);
    private static final String _isVisitedKey = BindExpressionBuilder.class + "_isVisted";
    protected final BindELContext _ctx;

    public BindExpressionBuilder(String expression, ELContext ctx) throws ELException {
        super(expression, ctx);
        _ctx = (BindELContext) ctx;
    }

    //20110815, allow handle value dot series script (e.g. x.y.z ? a.b.c : d.e.f)
    //will call back for each token node.
    public void visit(Node node) throws ELException {
        super.visit(node);
        visitNode(node);
    }

    @SuppressWarnings("unchecked")
    private static List<String> getSrcList(BindContext ctx) {
        return (List<String>) ctx.getAttribute(BinderImpl.SRCPATH);
    }

    private static Component getDependsOnComponent(BindContext ctx) {
        return (Component) ctx.getAttribute(BinderImpl.DEPENDS_ON_COMP);
    }

    //to tracing load property dependency or form field(both save and load)
    //path example, [vm,.p1,.firstName] or [fx.firstName]
    protected void addTracking(List<String> series) {
        final Binding binding = _ctx.getBinding();
        final boolean dotracker = !_ctx.ignoreTracker();

        if (binding != null && series != null && !series.isEmpty()) {

            //to prevent unnecessary from-save in nested expression in from binding and cause save error
            //e.g @bind(fx.hash[fx.key]) or @bind(vm.hash[fx.key]) 

            final Boolean isVisted = (Boolean) _ctx.getAttribute(_isVisitedKey);
            if (!Boolean.TRUE.equals(isVisted)) {
                _ctx.setAttribute(_isVisitedKey, Boolean.TRUE);
            }

            final Iterator<String> it = series.iterator();
            final String prop = (String) it.next();
            final Binder binder = binding.getBinder();
            final Tracker tracker = ((BinderCtrl) binder).getTracker();

            final BindContext bctx = (BindContext) _ctx.getAttribute(BinderImpl.BINDCTX);
            final List<String> srcpath = bctx != null ? getSrcList(bctx) : null;
            final Component dependsOnComp = bctx != null ? getDependsOnComponent(bctx) : null;
            final String[] srcprops = srcpath != null ? properties(srcpath) : null;
            //check if a PropertyBinding inside a Form
            final Component comp = bctx != null ? bctx.getComponent() : binding.getComponent();
            final Object base = comp.getAttribute(prop, true);
            final String fieldName = fieldName(it);
            
            if (fieldName != null) {
                if (base instanceof FormLegacy) { // ZK-4501: add SimpleForm back for compatibility
                    final FormLegacy formLegacyBean = (FormLegacy) base;
                    
                    if (binding instanceof SavePropertyBinding && !Boolean.TRUE.equals(isVisted)) {
                        if (_log.isDebugEnabled()) {
                            _log.debug("add save-field '%s' to form '%s'", fieldName, formLegacyBean);
                        }
                        if (formLegacyBean instanceof FormLegacyExt) {
                            ((FormLegacyExt) formLegacyBean).addSaveFieldName(fieldName);
                        }
                        ((BinderCtrl) binder).addFormAssociatedSaveBinding(comp, prop, (SavePropertyBinding) binding, fieldName);
                    } else if (binding instanceof LoadPropertyBinding
                            || binding instanceof LoadChildrenBinding || binding instanceof ReferenceBinding) {
                        if (_log.isDebugEnabled()) {
                            _log.debug("add load-field '%s' to form '%s'", fieldName, formLegacyBean);
                        }
                        if (formLegacyBean instanceof FormLegacyExt) {
                            ((FormLegacyExt) formLegacyBean).addLoadFieldName(fieldName);
                        }
                    }
                } else if (base instanceof Form) {
                    final Form formBean = (Form) base;
                    
                    if (binding instanceof SavePropertyBinding && !Boolean.TRUE.equals(isVisted)) {
                        if (_log.isDebugEnabled()) {
                            _log.debug("add save-field '{}' to form '{}'", fieldName, formBean);
                        }
                        ((BinderCtrl) binder).addSaveFormFieldName(formBean, fieldName);
                        ((BinderCtrl) binder).addFormAssociatedSaveBinding(comp, prop, (SavePropertyBinding) binding,
                                fieldName);
                    }
                }
            }

            //initialize Tracker per the series
            String[] props = properties(series);
            if (dotracker) {
                if (srcprops == null) {
                    tracker.addTracking(comp, props, binding);
                } else {
                    tracker.addDependsOn(comp, srcprops, binding, dependsOnComp, props);
                }
            }

            if (binding instanceof LoadFormBindingImpl) {
                ((LoadFormBindingImpl) binding).setSeriesLength(props.length);
            }
        }
    }

    protected void visitNode(Node node) {
        if (_ctx.getBinding() == null)
            return; //no need to build tracker, we are not in binding expression

        final List<String> path = new ArrayList<String>();
        //find the path from AST value node or AST identifier node
        if (node instanceof AstValue) {
            for (int j = 0, len = node.jjtGetNumChildren(); j < len; ++j) {
                final Node kid = node.jjtGetChild(j);
                path.add(BindELContext.toNodeString(kid, new StringBuffer()));
            }
            addTracking(path);
        } else if (node instanceof AstIdentifier) {
            if (!(node.jjtGetParent() instanceof AstValue)) { //one variable series
                path.add(BindELContext.toNodeString(node, new StringBuffer()));
                addTracking(path);
            }
        }
    }

    //remove prefix '.' for properties
    private String[] properties(List<String> series) {
        final String[] props = new String[series.size()];
        int j = 0;
        for (String prop : series) {
            if (prop.charAt(0) == '.') {
                prop = prop.substring(1);
            }
            props[j++] = prop;
        }
        return props;
    }

    //append rest field into form field name
    private String fieldName(Iterator<String> it) {
        final StringBuffer sb = new StringBuffer();
        while (it.hasNext()) {
            sb.append(it.next());
        }
        return sb.length() == 0 ? null : sb.charAt(0) == '.' ? sb.substring(1) : sb.toString();
    }
}