javax.activation.URLDataSource Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package javax.activation;
import java.net.URL;
import java.net.URLConnection;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
/**
* The URLDataSource class provides an object that wraps a URL
* object in a DataSource interface. URLDataSource simplifies the handling
* of data described by URLs within the JavaBeans Activation Framework
* because this class can be used to create new DataHandlers. NOTE: The
* DataHandler object creates a URLDataSource internally,
* when it is constructed with a URL.
*
* @see javax.activation.DataSource
* @see javax.activation.DataHandler
*/
public class URLDataSource implements DataSource {
private URL url = null;
private URLConnection url_conn = null;
/**
* URLDataSource constructor. The URLDataSource class will
* not open a connection to the URL until a method requiring it
* to do so is called.
*
* @param url The URL to be encapsulated in this object.
*/
public URLDataSource(URL url) {
this.url = url;
}
/**
* Returns the value of the URL content-type header field.
* It calls the URL's URLConnection.getContentType method
* after retrieving a URLConnection object.
* Note: this method attempts to call the openConnection
* method on the URL. If this method fails, or if a content type is not
* returned from the URLConnection, getContentType returns
* "application/octet-stream" as the content type.
*
* @return the content type.
*/
public String getContentType() {
String type = null;
try {
if (url_conn == null)
url_conn = url.openConnection();
} catch (IOException e) { }
if (url_conn != null)
type = url_conn.getContentType();
if (type == null)
type = "application/octet-stream";
return type;
}
/**
* Calls the getFile method on the URL used to
* instantiate the object.
*
* @return the result of calling the URL's getFile method.
*/
public String getName() {
return url.getFile();
}
/**
* The getInputStream method from the URL. Calls the
* openStream method on the URL.
*
* @return the InputStream.
*/
public InputStream getInputStream() throws IOException {
return url.openStream();
}
/**
* The getOutputStream method from the URL. First an attempt is
* made to get the URLConnection object for the URL. If that
* succeeds, the getOutputStream method on the URLConnection
* is returned.
*
* @return the OutputStream.
*/
public OutputStream getOutputStream() throws IOException {
// get the url connection if it is available
url_conn = url.openConnection();
if (url_conn != null) {
url_conn.setDoOutput(true);
return url_conn.getOutputStream();
} else
return null;
}
/**
* Return the URL used to create this DataSource.
*
* @return The URL.
*/
public URL getURL() {
return url;
}
}