/*

 * Copyright 2000-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.x509;

import java.io.IOException;

import java.io.OutputStream;

import java.util.*;

import sun.security.util.DerValue;

import sun.security.util.DerOutputStream;

/**

 * This class defines the certificate policies extension which specifies the

 * policies under which the certificate has been issued

 * and the purposes for which the certificate may be used.

 * <p>

 * Applications with specific policy requirements are expected to have a

 * list of those policies which they will accept and to compare the

 * policy OIDs in the certificate to that list.  If this extension is

 * critical, the path validation software MUST be able to interpret this

 * extension (including the optional qualifier), or MUST reject the

 * certificate.

 * <p>

 * Optional qualifiers are not supported in this implementation, as they are

 * not recommended by RFC2459.

 *

 * The ASN.1 syntax for this is (IMPLICIT tagging is defined in the

 * module definition):

 * <pre>

 * id-ce-certificatePolicies OBJECT IDENTIFIER ::=  { id-ce 32 }

 *

 * certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

 *

 * PolicyInformation ::= SEQUENCE {

 *      policyIdentifier   CertPolicyId,

 *      policyQualifiers   SEQUENCE SIZE (1..MAX) OF

 *                              PolicyQualifierInfo OPTIONAL }

 *

 * CertPolicyId ::= OBJECT IDENTIFIER

 * </pre>

 * @author Anne Anderson

 * @since       1.4

 * @see Extension

 * @see CertAttrSet

 */

public class CertificatePoliciesExtension extends Extension

implements CertAttrSet<String> {

    /**

     * Identifier for this attribute, to be used with the

     * get, set, delete methods of Certificate, x509 type.

     */

    public static final String IDENT = "x509.info.extensions.CertificatePolicies";

    /**

     * Attribute names.

     */

    public static final String NAME = "CertificatePolicies";

    public static final String POLICIES = "policies";

    /**

     * List of PolicyInformation for this object.

     */

    private List<PolicyInformation> certPolicies;

    // Encode this extension value.

    private void encodeThis() throws IOException {

        if (certPolicies == null || certPolicies.isEmpty()) {

            this.extensionValue = null;

        } else {

            DerOutputStream os = new DerOutputStream();

            DerOutputStream tmp = new DerOutputStream();

            for (PolicyInformation info : certPolicies) {

                info.encode(tmp);

            }

            os.write(DerValue.tag_Sequence, tmp);

            this.extensionValue = os.toByteArray();

        }

    }

    /**

     * Create a CertificatePoliciesExtension object from

     * a List of PolicyInformation; the criticality is set to false.

     *

     * @param certPolicies the List of PolicyInformation.

     */

    public CertificatePoliciesExtension(List<PolicyInformation> certPolicies)

    throws IOException {

        this(Boolean.FALSE, certPolicies);

    }

    /**

     * Create a CertificatePoliciesExtension object from

     * a List of PolicyInformation with specified criticality.

     *

     * @param critical true if the extension is to be treated as critical.

     * @param certPolicies the List of PolicyInformation.

     */

    public CertificatePoliciesExtension(Boolean critical,

            List<PolicyInformation> certPolicies) throws IOException {

        this.certPolicies = certPolicies;

        this.extensionId = PKIXExtensions.CertificatePolicies_Id;

        this.critical = critical.booleanValue();

        encodeThis();

    }

    /**

     * Create the extension from its DER encoded value and criticality.

     *

     * @param critical true if the extension is to be treated as critical.

     * @param value an array of DER encoded bytes of the actual value.

     * @exception ClassCastException if value is not an array of bytes

     * @exception IOException on error.

     */

    public CertificatePoliciesExtension(Boolean critical, Object value)

    throws IOException {

        this.extensionId = PKIXExtensions.CertificatePolicies_Id;

        this.critical = critical.booleanValue();

        this.extensionValue = (byte[]) value;

        DerValue val = new DerValue(this.extensionValue);

        if (val.tag != DerValue.tag_Sequence) {

            throw new IOException("Invalid encoding for " +

                                   "CertificatePoliciesExtension.");

        }

        certPolicies = new ArrayList<PolicyInformation>();

        while (val.data.available() != 0) {

            DerValue seq = val.data.getDerValue();

            PolicyInformation policy = new PolicyInformation(seq);

            certPolicies.add(policy);

        }

    }

    /**

     * Return the extension as user readable string.

     */

    public String toString() {

        if (certPolicies == null) {

            return "";

        }

        StringBuilder sb = new StringBuilder(super.toString());

        sb.append("CertificatePolicies [\n");

        for (PolicyInformation info : certPolicies) {

            sb.append(info.toString());

        }

        sb.append("]\n");

        return sb.toString();

    }

    /**

     * Write the extension to the DerOutputStream.

     *

     * @param out the DerOutputStream to write the extension to.

     * @exception IOException on encoding errors.

     */

    public void encode(OutputStream out) throws IOException {

        DerOutputStream tmp = new DerOutputStream();

        if (extensionValue == null) {

          extensionId = PKIXExtensions.CertificatePolicies_Id;

          critical = false;

          encodeThis();

        }

        super.encode(tmp);

        out.write(tmp.toByteArray());

    }

    /**

     * Set the attribute value.

     */

    public void set(String name, Object obj) throws IOException {

        if (name.equalsIgnoreCase(POLICIES)) {

            if (!(obj instanceof List)) {

                throw new IOException("Attribute value should be of type List.");

            }

            certPolicies = (List<PolicyInformation>)obj;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:CertificatePoliciesExtension.");

        }

        encodeThis();

    }

    /**

     * Get the attribute value.

     */

    public Object get(String name) throws IOException {

        if (name.equalsIgnoreCase(POLICIES)) {

            //XXXX May want to consider cloning this

            return certPolicies;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:CertificatePoliciesExtension.");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(POLICIES)) {

            certPolicies = null;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:CertificatePoliciesExtension.");

        }

        encodeThis();

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(POLICIES);

        return (elements.elements());

    }

    /**

     * Return the name of this attribute.

     */

    public String getName() {

        return (NAME);

    }

}