Spring Framework example source code file (OC4JClassPreprocessorAdapter.java)

This example Spring Framework source code file (OC4JClassPreprocessorAdapter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

cannot, classfiletransformer, classloader, classpreprocessor, classpreprocessor, illegalclassformatexception, illegalstateexception, oc4jclasspreprocessoradapter, oc4jclasspreprocessoradapter, override, protectiondomain, security, string, stringbuilder, transformer

The Spring Framework OC4JClassPreprocessorAdapter.java source code

/*
 * Copyright 2002-2006 the original author or authors.
 *
 * Licensed 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.springframework.instrument.classloading.oc4j;

import oracle.classloader.util.ClassPreprocessor;
import org.springframework.util.Assert;

import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;

/**
 * {@link ClassPreprocessor} adapter for OC4J, delegating to a standard
 * JDK {@link ClassFileTransformer} underneath.
 *
 * <p>Many thanks to Mike Keith
 * for his assistance.
 *
 * @author Costin Leau
 * @since 2.0
 */
class OC4JClassPreprocessorAdapter implements ClassPreprocessor {

	private final ClassFileTransformer transformer;


	/**
	 * Creates a new instance of the {@link OC4JClassPreprocessorAdapter} class.
	 * @param transformer the {@link ClassFileTransformer} to be adapted (must not be <code>null)
	 * @throws IllegalArgumentException if the supplied <code>transformer is null
	 */
	public OC4JClassPreprocessorAdapter(ClassFileTransformer transformer) {
		Assert.notNull(transformer, "Transformer must not be null");
		this.transformer = transformer;
	}


	public ClassPreprocessor initialize(ClassLoader loader) {
		return this;
	}

	public byte[] processClass(String className, byte origClassBytes[], int offset, int length, ProtectionDomain pd,
							   ClassLoader loader) {
		try {
			byte[] tempArray = new byte[length];
			System.arraycopy(origClassBytes, offset, tempArray, 0, length);

			// NB: OC4J passes className as "." without class while the
			// transformer expects a VM, "/" format
			byte[] result = this.transformer.transform(loader, className.replace('.', '/'), null, pd, tempArray);
			return (result != null ? result : origClassBytes);
		}
		catch (IllegalClassFormatException ex) {
			throw new IllegalStateException("Cannot transform because of illegal class format", ex);
		}
	}


	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder(getClass().getName());
		builder.append(" for transformer: ");
		builder.append(this.transformer);
		return builder.toString();
	}

}