org.hibernate.engine.jdbc.SerializableBlobProxy.java Source code

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Here is the source code for org.hibernate.engine.jdbc.SerializableBlobProxy.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.engine.jdbc;

import java.io.Serializable;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Blob;

import org.hibernate.HibernateException;

/**
 * Manages aspects of proxying {@link Blob Blobs} to add serializability.
 *
 * @author Gavin King
 * @author Steve Ebersole
 * @author Gail Badner
 */
public class SerializableBlobProxy implements InvocationHandler, Serializable {
    private static final Class[] PROXY_INTERFACES = new Class[] { Blob.class, WrappedBlob.class,
            Serializable.class };

    private final transient Blob blob;

    /**
     * Builds a serializable {@link Blob} wrapper around the given {@link Blob}.
     *
     * @param blob The {@link Blob} to be wrapped.
     * @see
     */
    private SerializableBlobProxy(Blob blob) {
        this.blob = blob;
    }

    /**
     * Access to the wrapped Blob reference
     *
     * @return The wrapped Blob reference
     */
    public Blob getWrappedBlob() {
        if (blob == null) {
            throw new IllegalStateException("Blobs may not be accessed after serialization");
        } else {
            return blob;
        }
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        if ("getWrappedBlob".equals(method.getName())) {
            return getWrappedBlob();
        }
        try {
            return method.invoke(getWrappedBlob(), args);
        } catch (AbstractMethodError e) {
            throw new HibernateException("The JDBC driver does not implement the method: " + method, e);
        } catch (InvocationTargetException e) {
            throw e.getTargetException();
        }
    }

    /**
     * Generates a SerializableBlob proxy wrapping the provided Blob object.
     *
     * @param blob The Blob to wrap.
     *
     * @return The generated proxy.
     */
    public static Blob generateProxy(Blob blob) {
        return (Blob) Proxy.newProxyInstance(getProxyClassLoader(), PROXY_INTERFACES,
                new SerializableBlobProxy(blob));
    }

    /**
     * Determines the appropriate class loader to which the generated proxy
     * should be scoped.
     *
     * @return The class loader appropriate for proxy construction.
     */
    public static ClassLoader getProxyClassLoader() {
        return WrappedBlob.class.getClassLoader();
    }
}