Resource

/*
 * Licensed to the University Corporation for Advanced Internet Development, 
 * Inc. (UCAID) under one or more contributor license agreements.  See the 
 * NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The UCAID licenses this file to You 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.opensaml.util.resource;

import java.io.InputStream;

import org.joda.time.DateTime;

/** An interface representing an data resource. */
public interface Resource {

    /**
     * Gets resource location information.  Examples might be filesystem path, URL, etc.
     * 
     * @return resource location information
     */
    public String getLocation();
    
    /**
     * Checks whether the resource exists.
     * 
     * @return true if the resource exists, false if not
     * 
     * @throws ResourceException thrown if there is a problem determining if the resource exists
     */
    public boolean exists() throws ResourceException;
    
    /**
     * Gets the inputstream to the resource's data.
     * 
     * @return inputstream to the resource's data
     * 
     * @throws ResourceException thrown if an input stream can not be created for the resource
     */
    public InputStream getInputStream() throws ResourceException;
    
    /**
     * Gets the date and time the resource was last modified.
     * 
     * @return date and time the resource was last modified
     * 
     * @throws ResourceException thrown if the last modified time can not be determined
     */
    public DateTime getLastModifiedTime() throws ResourceException;
}