001/* 002 * (C) Copyright 2007 Nuxeo SAS (http://nuxeo.com/) and contributors. 003 * 004 * All rights reserved. This program and the accompanying materials 005 * are made available under the terms of the GNU Lesser General Public License 006 * (LGPL) version 2.1 which accompanies this distribution, and is available at 007 * http://www.gnu.org/licenses/lgpl.html 008 * 009 * This library is distributed in the hope that it will be useful, 010 * but WITHOUT ANY WARRANTY; without even the implied warranty of 011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 012 * Lesser General Public License for more details. 013 * 014 * Contributors: 015 * Nuxeo - initial API and implementation 016 * 017 * $Id: MetaValueHolderRule.java 28460 2008-01-03 15:34:05Z sfermigier $ 018 */ 019 020package org.nuxeo.ecm.platform.ui.web.tag.jsf; 021 022import javax.el.ValueExpression; 023import javax.faces.component.UIComponent; 024import javax.faces.component.ValueHolder; 025import javax.faces.view.facelets.FaceletContext; 026import javax.faces.view.facelets.MetaRule; 027import javax.faces.view.facelets.Metadata; 028import javax.faces.view.facelets.MetadataTarget; 029import javax.faces.view.facelets.TagAttribute; 030 031import org.nuxeo.ecm.platform.ui.web.binding.MetaValueExpression; 032 033/** 034 * Meta value rule, used to evaluate an expression as a regular value expression, or invoking it again as another value 035 * expression or method expression. 036 * <p> 037 * The method can have parameters and the expression must use parentheses even if no parameters are needed. 038 * 039 * @author <a href="mailto:at@nuxeo.com">Anahide Tchertchian</a> 040 */ 041public class MetaValueHolderRule extends MetaRule { 042 043 static final class LiteralValueMetadata extends Metadata { 044 045 private final String value; 046 047 LiteralValueMetadata(String value) { 048 this.value = value; 049 } 050 051 @Override 052 public void applyMetadata(FaceletContext ctx, Object instance) { 053 ((ValueHolder) instance).setValue(value); 054 } 055 } 056 057 static final class MetaValueExpressionMetadata extends Metadata { 058 059 private final TagAttribute attr; 060 061 MetaValueExpressionMetadata(TagAttribute attr) { 062 this.attr = attr; 063 } 064 065 @Override 066 public void applyMetadata(FaceletContext ctx, Object instance) { 067 ValueExpression originalExpression = attr.getValueExpression(ctx, Object.class); 068 ((UIComponent) instance).setValueExpression("value", 069 new MetaValueExpression(originalExpression, ctx.getFunctionMapper(), ctx.getVariableMapper())); 070 } 071 } 072 073 public static final MetaValueHolderRule Instance = new MetaValueHolderRule(); 074 075 @Override 076 public Metadata applyRule(String name, TagAttribute attribute, MetadataTarget meta) { 077 if (meta.isTargetInstanceOf(ValueHolder.class)) { 078 if ("value".equals(name)) { 079 if (attribute.isLiteral()) { 080 return new LiteralValueMetadata(attribute.getValue()); 081 } else { 082 return new MetaValueExpressionMetadata(attribute); 083 } 084 } 085 086 } 087 return null; 088 } 089 090}