org.springframework.orm.jpa.persistenceunit.SpringPersistenceUnitInfo.java Source code

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Here is the source code for org.springframework.orm.jpa.persistenceunit.SpringPersistenceUnitInfo.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.orm.jpa.persistenceunit;

import javax.persistence.spi.ClassTransformer;

import org.springframework.core.DecoratingClassLoader;
import org.springframework.instrument.classloading.LoadTimeWeaver;
import org.springframework.instrument.classloading.SimpleThrowawayClassLoader;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Subclass of {@link MutablePersistenceUnitInfo} that adds instrumentation hooks based on
 * Spring's {@link org.springframework.instrument.classloading.LoadTimeWeaver} abstraction.
 *
 * <p>This class is restricted to package visibility, in contrast to its superclass.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Costin Leau
 * @since 2.0
 * @see PersistenceUnitManager
 */
class SpringPersistenceUnitInfo extends MutablePersistenceUnitInfo {

    @Nullable
    private LoadTimeWeaver loadTimeWeaver;

    @Nullable
    private ClassLoader classLoader;

    /**
     * Initialize this PersistenceUnitInfo with the LoadTimeWeaver SPI interface
     * used by Spring to add instrumentation to the current class loader.
     */
    public void init(LoadTimeWeaver loadTimeWeaver) {
        Assert.notNull(loadTimeWeaver, "LoadTimeWeaver must not be null");
        this.loadTimeWeaver = loadTimeWeaver;
        this.classLoader = loadTimeWeaver.getInstrumentableClassLoader();
    }

    /**
     * Initialize this PersistenceUnitInfo with the current class loader
     * (instead of with a LoadTimeWeaver).
     */
    public void init(@Nullable ClassLoader classLoader) {
        this.classLoader = classLoader;
    }

    /**
     * This implementation returns the LoadTimeWeaver's instrumentable ClassLoader,
     * if specified.
     */
    @Override
    @Nullable
    public ClassLoader getClassLoader() {
        return this.classLoader;
    }

    /**
     * This implementation delegates to the LoadTimeWeaver, if specified.
     */
    @Override
    public void addTransformer(ClassTransformer classTransformer) {
        if (this.loadTimeWeaver == null) {
            throw new IllegalStateException("Cannot apply class transformer without LoadTimeWeaver specified");
        }
        this.loadTimeWeaver.addTransformer(new ClassFileTransformerAdapter(classTransformer));
    }

    /**
     * This implementation delegates to the LoadTimeWeaver, if specified.
     */
    @Override
    public ClassLoader getNewTempClassLoader() {
        ClassLoader tcl = (this.loadTimeWeaver != null ? this.loadTimeWeaver.getThrowawayClassLoader()
                : new SimpleThrowawayClassLoader(this.classLoader));
        String packageToExclude = getPersistenceProviderPackageName();
        if (packageToExclude != null && tcl instanceof DecoratingClassLoader) {
            ((DecoratingClassLoader) tcl).excludePackage(packageToExclude);
        }
        return tcl;
    }

}