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Micro Distribution of the Payara Project for IBM JDK
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2012 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.enterprise.deployment.annotation.introspection;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
/**
* This class is encapsulating binary .class file information as
* defined at
* http://java.sun.com/docs/books/vmspec/2nd-edition/html/ClassFile.doc.html
*
* This is used by the annotation frameworks to quickly scan .class files
* for the presence of annotations. This avoid the annotation framework having
* to load each .class file in the class loader.
*
* The bytecode to be scanned could come from either a File (which lends itself
* easily to a channel) or from a JAR (which works better with a byte array). So
* we provide two variants of the containsAnnotation method, one for each.
*
* @author Jerome Dochez
*/
public class ClassFile {
ByteBuffer header;
ConstantPoolInfo constantPoolInfo;
/** Creates a new instance of ClassFile */
public ClassFile(ConstantPoolInfo poolInfo) {
header = ByteBuffer.allocate(12000);
constantPoolInfo = poolInfo;
}
/**
* Read the input channel and initialize instance data
* structure.
*/public boolean containsAnnotation(ReadableByteChannel in, long size) throws IOException {
header.clear();
if (size!=-1 && size>header.capacity()) {
// time to expand...
header = ByteBuffer.allocate((int) size);
}
long read = (long) in.read(header);
if (size!=-1 && read!=size) {
return false;
}
header.rewind();
return containsAnnotation(header);
}
/**
* Read the input channel and initialize instance data
* structure.
*/
public boolean containsAnnotation(final byte[] bytecode) throws IOException {
final ByteBuffer wrappedHeader = ByteBuffer.wrap(bytecode);
return containsAnnotation(wrappedHeader);
}
private boolean containsAnnotation(final ByteBuffer headerBuffer) throws IOException {
/**
* this is the .class file layout
*
ClassFile {
u4 magic;
u2 minor_version;
u2 major_version;
u2 constant_pool_count;
cp_info constant_pool[constant_pool_count-1];
u2 access_flags;
u2 this_class;
u2 super_class;
u2 interfaces_count;
u2 interfaces[interfaces_count];
u2 fields_count;
field_info fields[fields_count];
u2 methods_count;
method_info methods[methods_count];
u2 attributes_count;
attribute_info attributes[attributes_count];
}
**/
if (headerBuffer.getInt()!=magic) {
return false;
}
headerBuffer.getShort(); // major version
headerBuffer.getShort(); // minor version
int constantPoolSize = headerBuffer.getShort();
return constantPoolInfo.containsAnnotation(constantPoolSize, headerBuffer);
}
public ConstantPoolInfo constantPool[];
public short accessFlags;
public ConstantPoolInfo thisClass;
public ConstantPoolInfo superClass;
public ConstantPoolInfo interfaces[];
/**
* bunch of stuff I really don't care too much for now.
*
FieldInfo fields[];
MethodInfo methods[];
AttributeInfo attributes[];
*/
private static final int magic = 0xCAFEBABE;
public static final int ACC_PUBLIC = 0x1;
public static final int ACC_PRIVATE = 0x2;
public static final int ACC_PROTECTED = 0x4;
public static final int ACC_STATIC = 0x8;
public static final int ACC_FINAL = 0x10;
public static final int ACC_SYNCHRONIZED = 0x20;
public static final int ACC_THREADSAFE = 0x40;
public static final int ACC_TRANSIENT = 0x80;
public static final int ACC_NATIVE = 0x100;
public static final int ACC_INTERFACE = 0x200;
public static final int ACC_ABSTRACT = 0x400;
}
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