/*
* 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.axiom.om.util;
import org.apache.axiom.attachments.impl.BufferUtils;
import org.apache.axiom.attachments.utils.BAAInputStream;
import org.apache.axiom.attachments.utils.BAAOutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* FilterInputStream that delegates to the original
* InputStream. When detach() is called, the original
* InputStream is consumed, and closed. The unread bytes are
* stored in a local stream.
* Subsequent requests are serviced by the local stream.
*
* Rationale: The detached stream can be closed and its
* resources freed, but the consumer of the stream can
* continue to receive data.
*
* Cons: If there are a lot of bytes remaining, these are
* buffered. Currently they are buffered incore (this
* could be improved to buffer in a file).
*
*/
public class DetachableInputStream extends FilterInputStream {
private static Log log = LogFactory.getLog(DetachableInputStream.class);
private long count = 0;
BAAInputStream localStream = null;
boolean isClosed = false;
public DetachableInputStream(InputStream in) {
super(in);
count = 0;
}
/**
* @return count of bytes read
*/
public long length() throws IOException {
if (localStream == null) {
detach();
}
return count;
}
/**
* Consume the input stream and close it.
* The bytes in the input stream are buffered.
* (Thus the original input stream can release its
* resources, but the consumer of the stream can
* still receive data).
* @throws IOException
*/
public void detach() throws IOException {
if (localStream == null && !isClosed) {
BAAOutputStream baaos = new BAAOutputStream();
try {
// It is possible that the underlying stream was closed
BufferUtils.inputStream2OutputStream(in, baaos);
super.close();
} catch (Throwable t) {
if (log.isDebugEnabled()) {
log.debug("detach caught exception. Processing continues:"
+ t);
log.debug(" " + stackToString(t));
}
} finally {
in = null; // GC the incoming stream
}
localStream = new BAAInputStream(baaos.buffers(), baaos.length());
if (log.isDebugEnabled()) {
log.debug("The local stream built from the detached " +
"stream has a length of:" + baaos.length());
}
count = count + baaos.length();
}
}
public int available() throws IOException {
if (localStream != null) {
return localStream.available();
} else {
return super.available();
}
}
public void close() throws IOException {
isClosed = true;
if (localStream != null) {
localStream.close();
} else {
super.close();
}
}
public boolean markSupported() {
// Mark is not supported because stream can
// switch
return false;
}
public synchronized void mark(int readlimit) {
throw new UnsupportedOperationException();
}
public int read() throws IOException {
if (localStream == null) {
int rc = super.read();
if (rc != -1) {
count++;
}
return rc;
} else {
return localStream.read();
}
}
public int read(byte[] b, int off, int len) throws IOException {
if (localStream == null) {
int rc = super.read(b, off, len);
if (rc > 0) {
count += rc;
}
return rc;
} else {
return localStream.read(b, off, len);
}
}
public int read(byte[] b) throws IOException {
if (localStream == null) {
int rc = super.read(b);
if (rc > 0) {
count += rc;
}
return rc;
} else {
return localStream.read(b);
}
}
public synchronized void reset() throws IOException {
throw new IOException();
}
public long skip(long n) throws IOException {
if (localStream == null) {
long rc = super.skip(n);
if (rc > 0) {
count += rc;
}
return rc;
} else {
return localStream.skip(n);
}
}
private static String stackToString(Throwable e) {
java.io.StringWriter sw = new java.io.StringWriter();
java.io.BufferedWriter bw = new java.io.BufferedWriter(sw);
java.io.PrintWriter pw = new java.io.PrintWriter(bw);
e.printStackTrace(pw);
pw.close();
String text = sw.getBuffer().toString();
return text;
}
}