org.springframework.instrument.classloading.SimpleLoadTimeWeaver.java Source code

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Here is the source code for org.springframework.instrument.classloading.SimpleLoadTimeWeaver.java

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/*
 * Copyright 2002-2017 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
 *
 *      https://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;

import java.lang.instrument.ClassFileTransformer;

import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * {@code LoadTimeWeaver} that builds and exposes a
 * {@link SimpleInstrumentableClassLoader}.
 *
 * <p>Mainly intended for testing environments, where it is sufficient to
 * perform all class transformation on a newly created
 * {@code ClassLoader} instance.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @since 2.0
 * @see #getInstrumentableClassLoader()
 * @see SimpleInstrumentableClassLoader
 * @see ReflectiveLoadTimeWeaver
 */
public class SimpleLoadTimeWeaver implements LoadTimeWeaver {

    private final SimpleInstrumentableClassLoader classLoader;

    /**
     * Create a new {@code SimpleLoadTimeWeaver} for the current context
     * {@code ClassLoader}.
     * @see SimpleInstrumentableClassLoader
     */
    public SimpleLoadTimeWeaver() {
        this.classLoader = new SimpleInstrumentableClassLoader(ClassUtils.getDefaultClassLoader());
    }

    /**
     * Create a new {@code SimpleLoadTimeWeaver} for the given
     * {@code ClassLoader}.
     * @param classLoader the {@code ClassLoader} to build a simple
     * instrumentable {@code ClassLoader} on top of
     */
    public SimpleLoadTimeWeaver(SimpleInstrumentableClassLoader classLoader) {
        Assert.notNull(classLoader, "ClassLoader must not be null");
        this.classLoader = classLoader;
    }

    @Override
    public void addTransformer(ClassFileTransformer transformer) {
        this.classLoader.addTransformer(transformer);
    }

    @Override
    public ClassLoader getInstrumentableClassLoader() {
        return this.classLoader;
    }

    /**
     * This implementation builds a {@link SimpleThrowawayClassLoader}.
     */
    @Override
    public ClassLoader getThrowawayClassLoader() {
        return new SimpleThrowawayClassLoader(getInstrumentableClassLoader());
    }

}