/* ********************************************************************** **
** Copyright notice **
** **
** (c) 2005-2006 RSSOwl Development Team **
** http://www.rssowl.org/ **
** **
** All rights reserved **
** **
** This program and the accompanying materials are made available under **
** the terms of the Eclipse Public License v1.0 which accompanies this **
** distribution, and is available at: **
** http://www.rssowl.org/legal/epl-v10.html **
** **
** A copy is found in the file epl-v10.html and important notices to the **
** license from the team is found in the textfile LICENSE.txt distributed **
** in this package. **
** **
** This copyright notice MUST APPEAR in all copies of the file! **
** **
** Contributors: **
** RSSOwl Development Team - initial API and implementation **
** **
** ********************************************************************** */
package org.rssowl.core.internal.connection;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.methods.GetMethod;
import org.eclipse.core.runtime.IProgressMonitor;
import org.rssowl.core.connection.IConditionalGetCompatible;
import org.rssowl.core.connection.MonitorCanceledException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* <p>
* This kind of FilterInputStream makes sure that the GetMethod responsible for
* the given InputStream is releasing its connection after the stream has been
* closed. This class is also keeping two important headers to be used for the
* Conditional GET Mechanism of HTTP.
* </p>
* <p>
* Passing an instance of <code>IProgressMonitor</code> into the class allows
* for early cancelation by throwing an Exception from the various
* stream-methods as soon as the monitor is canceled.
* </p>
*
* @author bpasero
*/
public class HttpConnectionInputStream extends FilterInputStream implements IConditionalGetCompatible {
/* Request Header */
private static final String HEADER_RESPONSE_ETAG = "ETag"; //$NON-NLS-1$
private static final String HEADER_RESPONSE_LAST_MODIFIED = "Last-Modified"; //$NON-NLS-1$
private GetMethod fGetMethod;
private IProgressMonitor fMonitor;
private String fIfModifiedSince;
private String fIfNoneMatch;
/**
* Creates a <code>HttpConnectionInputStream</code> by assigning the
* argument <code>inS</code> to the field <code>this.in</code> so as to
* remember it for later use.
*
* @param getMethod The Method holding the connection of the given Stream.
* @param monitor A ProgressMonitor to support early cancelation, or
* <code>NULL</code> if no monitor is being used.
* @param inS the underlying input Stream.
*/
public HttpConnectionInputStream(GetMethod getMethod, IProgressMonitor monitor, InputStream inS) {
super(inS);
fGetMethod = getMethod;
fMonitor = monitor;
/* Keep some important Headers */
Header headerLastModified = getMethod.getResponseHeader(HEADER_RESPONSE_LAST_MODIFIED);
if (headerLastModified != null)
setIfModifiedSince(headerLastModified.getValue());
Header headerETag = getMethod.getResponseHeader(HEADER_RESPONSE_ETAG);
if (headerETag != null)
setIfNoneMatch(headerETag.getValue());
}
/*
* @see org.rssowl.core.connection.internal.http.IConditionalGetCompatible#getIfModifiedSince()
*/
public String getIfModifiedSince() {
return fIfModifiedSince;
}
/*
* @see org.rssowl.core.connection.internal.http.IConditionalGetCompatible#getIfNoneMatch()
*/
public String getIfNoneMatch() {
return fIfNoneMatch;
}
/*
* @see org.rssowl.core.connection.internal.http.IConditionalGetCompatible#setIfModifiedSince(java.lang.String)
*/
public void setIfModifiedSince(String ifModifiedSince) {
fIfModifiedSince = ifModifiedSince;
}
/*
* @see org.rssowl.core.connection.internal.http.IConditionalGetCompatible#setIfNoneMatch(java.lang.String)
*/
public void setIfNoneMatch(String ifNoneMatch) {
fIfNoneMatch = ifNoneMatch;
}
@Override
public void close() throws IOException {
super.close();
fGetMethod.releaseConnection();
}
@Override
public int read() throws IOException {
/* Support early cancelation */
if (fMonitor != null && fMonitor.isCanceled())
throw new MonitorCanceledException("Connection canceled"); //$NON-NLS-1$
return super.read();
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
/* Support early cancelation */
if (fMonitor != null && fMonitor.isCanceled())
throw new MonitorCanceledException("Connection canceled"); //$NON-NLS-1$
return super.read(b, off, len);
}
@Override
public int available() throws IOException {
/* Support early cancelation */
if (fMonitor != null && fMonitor.isCanceled())
throw new MonitorCanceledException("Connection canceled"); //$NON-NLS-1$
return super.available();
}
}