/*
 * Copyright 2010-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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 com.amazonaws.services.s3.model;

import java.security.KeyPair;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.SecretKey;

/**
 * The "key encrypting key" materials used in encrypt/decryption. These
 * materials may be either an asymmetric key pair or a symmetric key but not
 * both.
 */
public class EncryptionMaterials {
    private final KeyPair keyPair;
    private final SecretKey symmetricKey;

    /**
     * Constructs a new EncryptionMaterials object, storing an asymmetric key
     * pair.
     *
     * @param keyPair The asymmetric key pair to be stored in this
     *            EncryptionMaterials object.
     */
    public EncryptionMaterials(KeyPair keyPair) {
        this(keyPair, null);
    }

    /**
     * Constructs a new EncryptionMaterials object, storing a symmetric key.
     *
     * @param symmetricKey The symmetric key to be stored in this
     *            EncryptionMaterials object.
     */
    public EncryptionMaterials(SecretKey symmetricKey) {
        this(null, symmetricKey);
    }

    /**
     * Base constructor for the EncryptionMaterials object. This is not publicly
     * visible since it should not be possible to create an EncryptionMaterials
     * object that contains both an asymmetric key pair and a symmetric key.
     */
    protected EncryptionMaterials(KeyPair keyPair, SecretKey symmetricKey) {
        this.keyPair = keyPair;
        this.symmetricKey = symmetricKey;
    }

    /**
     * Returns the key pair stored in this EncryptionMaterials object.
     *
     * @return the key pair stored in this EncryptionMaterials object.
     */
    public KeyPair getKeyPair() {
        return this.keyPair;
    }

    /**
     * Returns the symmetric key stored in this EncryptionMaterials object.
     *
     * @return the symmetric key stored in this EncryptionMaterials object.
     */
    public SecretKey getSymmetricKey() {
        return this.symmetricKey;
    }

    /**
     * Returns an empty map since the EncryptionMaterials base class does not
     * have extra materials information. Subclasses may override this method.
     *
     * @return an empty <String, String> map
     */
    public Map<String, String> getMaterialsDescription() {
        return new HashMap<String, String>();
    }

    /**
     * Returns null since the EncryptionMaterials base class does not have a
     * materials accessor. Subclasses may override this method.
     *
     * @return null
     */
    public EncryptionMaterialsAccessor getAccessor() {
        return null;
    }
}