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* Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package jdk.internal.loader;
import java.io.EOFException;
import java.net.URL;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.InputStream;
import java.security.CodeSigner;
import java.util.jar.Manifest;
import java.nio.ByteBuffer;
import java.util.Arrays;
import sun.nio.ByteBuffered;
This class is used to represent a Resource that has been loaded
from the class path.
Author: David Connelly Since: 1.2
/**
* This class is used to represent a Resource that has been loaded
* from the class path.
*
* @author David Connelly
* @since 1.2
*/
public abstract class Resource {
Returns the name of the Resource.
/**
* Returns the name of the Resource.
*/
public abstract String getName();
Returns the URL of the Resource.
/**
* Returns the URL of the Resource.
*/
public abstract URL getURL();
Returns the CodeSource URL for the Resource.
/**
* Returns the CodeSource URL for the Resource.
*/
public abstract URL getCodeSourceURL();
Returns an InputStream for reading the Resource data.
/**
* Returns an InputStream for reading the Resource data.
*/
public abstract InputStream getInputStream() throws IOException;
Returns the length of the Resource data, or -1 if unknown.
/**
* Returns the length of the Resource data, or -1 if unknown.
*/
public abstract int getContentLength() throws IOException;
private InputStream cis;
/* Cache result in case getBytes is called after getByteBuffer. */
private synchronized InputStream cachedInputStream() throws IOException {
if (cis == null) {
cis = getInputStream();
}
return cis;
}
Returns the Resource data as an array of bytes.
/**
* Returns the Resource data as an array of bytes.
*/
public byte[] getBytes() throws IOException {
byte[] b;
// Get stream before content length so that a FileNotFoundException
// can propagate upwards without being caught too early
InputStream in = cachedInputStream();
// This code has been uglified to protect against interrupts.
// Even if a thread has been interrupted when loading resources,
// the IO should not abort, so must carefully retry, failing only
// if the retry leads to some other IO exception.
boolean isInterrupted = Thread.interrupted();
int len;
for (;;) {
try {
len = getContentLength();
break;
} catch (InterruptedIOException iioe) {
Thread.interrupted();
isInterrupted = true;
}
}
try {
b = new byte[0];
if (len == -1) len = Integer.MAX_VALUE;
int pos = 0;
while (pos < len) {
int bytesToRead;
if (pos >= b.length) { // Only expand when there's no room
bytesToRead = Math.min(len - pos, b.length + 1024);
if (bytesToRead < 0) {
// Can overflow only due to large b.length
bytesToRead = len - pos;
}
b = Arrays.copyOf(b, pos + bytesToRead);
} else {
bytesToRead = b.length - pos;
}
int cc = 0;
try {
cc = in.read(b, pos, bytesToRead);
} catch (InterruptedIOException iioe) {
Thread.interrupted();
isInterrupted = true;
}
if (cc < 0) {
if (len != Integer.MAX_VALUE) {
throw new EOFException("Detect premature EOF");
} else {
if (b.length != pos) {
b = Arrays.copyOf(b, pos);
}
break;
}
}
pos += cc;
}
} finally {
try {
in.close();
} catch (InterruptedIOException iioe) {
isInterrupted = true;
} catch (IOException ignore) {}
if (isInterrupted) {
Thread.currentThread().interrupt();
}
}
return b;
}
Returns the Resource data as a ByteBuffer, but only if the input stream was implemented on top of a ByteBuffer. Return null otherwise. Returns: Resource data or null.
/**
* Returns the Resource data as a ByteBuffer, but only if the input stream
* was implemented on top of a ByteBuffer. Return {@code null} otherwise.
* @return Resource data or null.
*/
public ByteBuffer getByteBuffer() throws IOException {
InputStream in = cachedInputStream();
if (in instanceof ByteBuffered) {
return ((ByteBuffered)in).getByteBuffer();
}
return null;
}
Returns the Manifest for the Resource, or null if none.
/**
* Returns the Manifest for the Resource, or null if none.
*/
public Manifest getManifest() throws IOException {
return null;
}
Returns theCertificates for the Resource, or null if none.
/**
* Returns theCertificates for the Resource, or null if none.
*/
public java.security.cert.Certificate[] getCertificates() {
return null;
}
Returns the code signers for the Resource, or null if none.
/**
* Returns the code signers for the Resource, or null if none.
*/
public CodeSigner[] getCodeSigners() {
return null;
}
}