BindExpressionBuilder.java

/* 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.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.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);
			if (base instanceof Form) {
				final Form formBean = (Form) base;
				final String fieldName = fieldName(it);

				if (fieldName != null) {
					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();
	}
}