001// Copyright 2012-2013 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.http.internal.util;
016
017import org.apache.tapestry5.ioc.services.SymbolProvider;
018
019/**
020 * Combines multiple symbol providers.
021 *
022 * @since 5.4
023 */
024public class DelegatingSymbolProvider implements SymbolProvider
025{
026    private final SymbolProvider[] providers;
027
028    public DelegatingSymbolProvider(SymbolProvider... providers)
029    {
030        this.providers = providers;
031    }
032
033    public String valueForSymbol(String symbolName)
034    {
035        for (SymbolProvider p : providers)
036        {
037            String value = p.valueForSymbol(symbolName);
038
039            if (value != null)
040            {
041                return value;
042            }
043        }
044
045        return null;
046    }
047}