org.apache.nifi.components.resource.ResourceReference Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.nifi.components.resource;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
/**
* A reference to a Resource that is identified by a property value
*/
public interface ResourceReference {
/**
* @return a file representation of the resource, or null if the Resource cannot be represented as a File
*/
File asFile();
/**
* @return a URL representation of the resource, or null if the Resource cannot be represented as a URL
*/
URL asURL();
/**
* @return an InputStream to read the contents of the resource
*
* @throws IOException if unable to obtain an InputStream from the resource
*/
InputStream read() throws IOException;
/**
* Indicates whether or not the resource is accessible. What it means for the resource to be accessible depends on the type of
* resource. A File resource, for example, might be accessible only if the file exists and is readable, while a URL resource might
* always be considered accessible, or might be accesssible only if the existence of the resource can be confirmed.
*
* @return true if the file can be accessed, false otherwise
*/
boolean isAccessible();
/**
* @return a String representation of the location, or null for a Resource that does not have an external location.
* For a File or a Directory, this will be the full path name; for a URL it will be the String form of the URL
*/
String getLocation();
/**
* @return the type of resource that is being referenced
*/
ResourceType getResourceType();
}