org.hibernate.bytecode.spi.ByteCodeHelper Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.bytecode.spi;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipInputStream;
/**
* A helper for reading byte code from various input sources.
*
* @author Steve Ebersole
*/
public class ByteCodeHelper {
/**
* Disallow instantiation (its a helper)
*/
private ByteCodeHelper() {
}
/**
* Reads class byte array info from the given input stream.
*
* The stream is closed within this method!
*
* @param inputStream The stream containing the class binary; null will lead to an {@link IOException}
*
* @return The read bytes
*
* @throws IOException Indicates a problem accessing the given stream.
*/
public static byte[] readByteCode(InputStream inputStream) throws IOException {
if ( inputStream == null ) {
throw new IOException( "null input stream" );
}
final byte[] buffer = new byte[409600];
byte[] classBytes = new byte[0];
try {
int r = inputStream.read( buffer );
while ( r >= buffer.length ) {
final byte[] temp = new byte[ classBytes.length + buffer.length ];
// copy any previously read bytes into the temp array
System.arraycopy( classBytes, 0, temp, 0, classBytes.length );
// copy the just read bytes into the temp array (after the previously read)
System.arraycopy( buffer, 0, temp, classBytes.length, buffer.length );
classBytes = temp;
// read the next set of bytes into buffer
r = inputStream.read( buffer );
}
if ( r != -1 ) {
final byte[] temp = new byte[ classBytes.length + r ];
// copy any previously read bytes into the temp array
System.arraycopy( classBytes, 0, temp, 0, classBytes.length );
// copy the just read bytes into the temp array (after the previously read)
System.arraycopy( buffer, 0, temp, classBytes.length, r );
classBytes = temp;
}
}
finally {
try {
inputStream.close();
}
catch (IOException ignore) {
// intentionally empty
}
}
return classBytes;
}
/**
* Read class definition from a file.
*
* @param file The file to read.
*
* @return The class bytes
*
* @throws IOException Indicates a problem accessing the given stream.
*/
public static byte[] readByteCode(File file) throws IOException {
return ByteCodeHelper.readByteCode( new FileInputStream( file ) );
}
/**
* Read class definition a zip (jar) file entry.
*
* @param zip The zip entry stream.
*
* @return The class bytes
*
* @throws IOException Indicates a problem accessing the given stream.
*/
public static byte[] readByteCode(ZipInputStream zip) throws IOException {
final ByteArrayOutputStream bout = new ByteArrayOutputStream();
final InputStream in = new BufferedInputStream( zip );
int b;
while ( ( b = in.read() ) != -1 ) {
bout.write( b );
}
return bout.toByteArray();
}
}