/*
 * Copyright 2008 the original author or authors.
 * 
 * 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.wamblee.system.components;

import java.io.IOException;
import java.util.Properties;

import org.wamblee.io.InputResource;
import org.wamblee.system.core.AbstractComponent;
import org.wamblee.system.core.DefaultProvidedInterface;
import org.wamblee.system.core.ProvidedInterface;
import org.wamblee.system.core.Scope;

/**
 * Property component that reads a property file and provides
 * it to other components through a provided interface.
 * 
 * NOTE: when multiple property components are used, disambiguation
 * of provided and required interfaces is needed. 
 *  
 * @author Erik Brakkee
 */
public class PropertyComponent extends AbstractComponent<Properties> {
    
    private static ProvidedInterface PROPS = new DefaultProvidedInterface("props", Properties.class);
    
    private Properties props;
    
    public PropertyComponent(String aName, InputResource aResource) throws IOException { 
        this(aName, readProps(aResource)); 
    }
    
    private static Properties readProps(InputResource aResource) throws IOException {
        Properties props = new Properties(); 
        props.load(aResource.getInputStream());
        return props; 
    }

    public PropertyComponent(String aName, Properties aProps) {
        super(aName);
        props = aProps; 
        
        addProvidedInterface(PROPS);
    }

    @Override
    protected Properties doStart(Scope aScope) {
        addInterface(PROPS, props, aScope);
        return props; 
    }

    @Override
    protected void doStop(Properties aRuntime) {
        // Empty 
    }

}