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/* VariableResolverInfo.java

	Purpose:
		
	Description:
		
	History:
		Thu Jun  1 18:12:56     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.metainfo;

import java.util.Map;

import org.zkoss.lang.Classes;
import org.zkoss.xel.VariableResolver;

import org.zkoss.zk.ui.Page;
import org.zkoss.zk.ui.UiException;
import org.zkoss.zk.xel.ExValue;
import org.zkoss.zk.xel.Evaluator;

/**
 * A definition of the variable resolver ({@link VariableResolver}).
 *
 * 

Note: we resolve the class by using Classes.forNameByThread. * In other words, it doesn't support the class defined in zscript. * Why not? Since there is no way to run zscript before * the variable-resolver directive (and better performance). *

*

Note: it is not serializable.

* * @author tomyeh */ public class VariableResolverInfo extends ArgumentInfo { //directive // private static final Log log = Log.lookup(VariableResolverInfo.class); /** A class, an ExValue or an VariableResolver. */ private Object _resolver; /** Constructs with a class. * @param args the map of arguments. Ignored if null.
* Notice that, once assigned, the map belongs to this object, and the caller * shall not access it again * @since 3.6.2 */ public VariableResolverInfo(Class cls, Map args) { super(args); checkClass(cls); _resolver = cls; } /** Constructs with a class. */ public VariableResolverInfo(Class cls) { this(cls, null); } private static void checkClass(Class cls) { if (!VariableResolver.class.isAssignableFrom(cls)) throw new UiException(VariableResolver.class+" must be implemented: "+cls); } /** Constructs with a class name. * * @param clsnm the class name; it could be an EL expression. * @since 3.6.2 */ public VariableResolverInfo(String clsnm, Map args) throws ClassNotFoundException { super(args); if (clsnm == null || clsnm.length() == 0) throw new IllegalArgumentException("empty"); if (clsnm.indexOf("${") < 0) { if (clsnm.indexOf('.') >= 0) { //resolve it now try { final Class cls = Classes.forNameByThread(clsnm); checkClass(cls); _resolver = cls; } catch (ClassNotFoundException ex) { throw new ClassNotFoundException("Class not found: "+clsnm, ex); } } else { //it might depend on _resolver = clsnm; } } else { _resolver = new ExValue(clsnm, String.class); } } /** Constructs with a class name. * * @param clsnm the class name; it could be an EL expression. */ public VariableResolverInfo(String clsnm) throws ClassNotFoundException { this(clsnm, null); } /** Constructs with an initiator that will be reuse each time * {@link #newVariableResolver} is called. */ public VariableResolverInfo(VariableResolver resolver) { super(null); if (resolver == null) throw new IllegalArgumentException("null"); _resolver = resolver; } /** Creates and returns the variable resolver for the specified page. */ public VariableResolver newVariableResolver(PageDefinition pgdef, Page page) throws Exception { return newVariableResolver(pgdef.getEvaluator(), page); } /** Creates and returns the variable resolver for the specified page. * @since 3.6.2 */ public VariableResolver newVariableResolver(Evaluator eval, Page page) throws Exception { if (_resolver instanceof VariableResolver) return (VariableResolver)_resolver; String clsnm = null; if (_resolver instanceof ExValue) { clsnm = (String)((ExValue)_resolver).getValue(eval, page); if (clsnm == null || clsnm.length() == 0) { // if (log.debugable()) log.debug("Ignore "+_resolver+" due to empty"); return null; //ignore it!! } } else if (_resolver instanceof String) { clsnm = (String)_resolver; } final Class cls; if (clsnm != null) { try { cls = page != null ? page.resolveClass(clsnm): Classes.forNameByThread(clsnm); checkClass(cls); } catch (ClassNotFoundException ex) { throw new ClassNotFoundException("Class not found: "+clsnm+" ("+_resolver+")", ex); } if (clsnm.equals(_resolver)) _resolver = cls; //cache it for better performance } else { cls = (Class)_resolver; } return (VariableResolver)newInstance(cls, eval, page); } //Object// public String toString() { return "[variable-resolver " + _resolver + "]"; } }




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