/*
 * Copyright (c) 2011, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     James Sutherland (Oracle) - initial API and implementation
package org.eclipse.persistence.descriptors.partitioning;

import java.util.List;

import org.eclipse.persistence.exceptions.ValidationException;
import org.eclipse.persistence.internal.databaseaccess.Accessor;
import org.eclipse.persistence.internal.security.PrivilegedAccessHelper;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.queries.DatabaseQuery;

/**
 * PUBLIC:
 * Defines a user defined partitioning policy.
 * Used by metadata to defer class loading to init.
 * @author James Sutherland
 * @since EclipseLink 2.2
 */
public class CustomPartitioningPolicy extends PartitioningPolicy {

    protected String partitioningClasName;

    protected PartitioningPolicy policy;

    public CustomPartitioningPolicy() {
    }

    /**
     * INTERNAL:
     * Initialize the policy.
     */
    @Override
    public void initialize(AbstractSession session) {

    }

    /**
     * INTERNAL:
     * Convert all the class-name-based settings to actual class-based
     * settings. This method is used when converting a project that has been built
     * with class names to a project with classes.
     */
    @Override
    public void convertClassNamesToClasses(ClassLoader classLoader) {
        if (getPartitioningClasName() == null) {
            setPartitioningClasName("");
        }
        this.policy = PrivilegedAccessHelper.callDoPrivilegedWithException(
                () -> {
                    final Class<? extends PartitioningPolicy> partitioningClass
                            = PrivilegedAccessHelper.getClassForName(getPartitioningClasName(), true, classLoader);
                    return PrivilegedAccessHelper.newInstanceFromClass(partitioningClass);
                },
                (ex) -> {
                    if (ex instanceof ClassNotFoundException) {
                        return ValidationException.classNotFoundWhileConvertingClassNames(getPartitioningClasName(), ex);
                    } else if (ex instanceof IllegalAccessException) {
                        return ValidationException.reflectiveExceptionWhileCreatingClassInstance(getPartitioningClasName(), ex);
                    } else if (ex instanceof InstantiationException) {
                        return ValidationException.reflectiveExceptionWhileCreatingClassInstance(getPartitioningClasName(), ex);
                    }
                    return new RuntimeException("Could not convert class names to classes", ex);
                }
        );
    }

    /**
     * INTERNAL:
     * Forward to custom policy
     */
    @Override
    public List<Accessor> getConnectionsForQuery(AbstractSession session, DatabaseQuery query, AbstractRecord arguments) {
        return policy.getConnectionsForQuery(session, query, arguments);
    }

    public String getPartitioningClasName() {
        return partitioningClasName;
    }

    public void setPartitioningClasName(String partitioningClasName) {
        this.partitioningClasName = partitioningClasName;
    }

    public PartitioningPolicy getPolicy() {
        return policy;
    }

    public void setPolicy(PartitioningPolicy policy) {
        this.policy = policy;
    }

}