/*
 * Copyright 2004-2009 the Seasar Foundation and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.seasar.mayaa.impl.cycle.jsp;

import javax.servlet.jsp.el.VariableResolver;

import org.seasar.mayaa.cycle.scope.AttributeScope;
import org.seasar.mayaa.impl.cycle.CycleUtil;
import org.seasar.mayaa.impl.util.StringUtil;

/**
 * @author Masataka Kurihara (Gluegent, Inc.)
 */
public class VariableResolverImpl implements VariableResolver {

    private static VariableResolver _instance = new VariableResolverImpl();

    public static VariableResolver getInstance() {
        return _instance;
    }

    public Object resolveVariable(String pName) {
        if (StringUtil.hasValue(pName)) {
            AttributeScope scope = CycleUtil.findStandardAttributeScope(pName);
            if (scope != null) {
                return scope.getAttribute(pName);
            }
        }
        return null;
    }

}
