Java tutorial
/* * Copyright (c) 2000, 2013, Oracle and/or its affiliates. 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.security.cert; import java.security.KeyStore; import java.security.KeyStoreException; import java.security.InvalidAlgorithmParameterException; import java.security.InvalidParameterException; import java.util.Set; /** * Parameters used as input for the PKIX {@code CertPathBuilder} * algorithm. * <p> * A PKIX {@code CertPathBuilder} uses these parameters to {@link * CertPathBuilder#build build} a {@code CertPath} which has been * validated according to the PKIX certification path validation algorithm. * * <p>To instantiate a {@code PKIXBuilderParameters} object, an * application must specify one or more <i>most-trusted CAs</i> as defined by * the PKIX certification path validation algorithm. The most-trusted CA * can be specified using one of two constructors. An application * can call {@link #PKIXBuilderParameters(Set, CertSelector) * PKIXBuilderParameters(Set, CertSelector)}, specifying a * {@code Set} of {@code TrustAnchor} objects, each of which * identifies a most-trusted CA. Alternatively, an application can call * {@link #PKIXBuilderParameters(KeyStore, CertSelector) * PKIXBuilderParameters(KeyStore, CertSelector)}, specifying a * {@code KeyStore} instance containing trusted certificate entries, each * of which will be considered as a most-trusted CA. * * <p>In addition, an application must specify constraints on the target * certificate that the {@code CertPathBuilder} will attempt * to build a path to. The constraints are specified as a * {@code CertSelector} object. These constraints should provide the * {@code CertPathBuilder} with enough search criteria to find the target * certificate. Minimal criteria for an {@code X509Certificate} usually * include the subject name and/or one or more subject alternative names. * If enough criteria is not specified, the {@code CertPathBuilder} * may throw a {@code CertPathBuilderException}. * <p> * <b>Concurrent Access</b> * <p> * Unless otherwise specified, the methods defined in this class are not * thread-safe. Multiple threads that need to access a single * object concurrently should synchronize amongst themselves and * provide the necessary locking. Multiple threads each manipulating * separate objects need not synchronize. * * @see CertPathBuilder * * @since 1.4 * @author Sean Mullan */ public class PKIXBuilderParameters extends PKIXParameters { private int maxPathLength = 5; /** * Creates an instance of {@code PKIXBuilderParameters} with * the specified {@code Set} of most-trusted CAs. * Each element of the set is a {@link TrustAnchor TrustAnchor}. * * <p>Note that the {@code Set} is copied to protect against * subsequent modifications. * * @param trustAnchors a {@code Set} of {@code TrustAnchor}s * @param targetConstraints a {@code CertSelector} specifying the * constraints on the target certificate * @throws InvalidAlgorithmParameterException if {@code trustAnchors} * is empty {@code (trustAnchors.isEmpty() == true)} * @throws NullPointerException if {@code trustAnchors} is * {@code null} * @throws ClassCastException if any of the elements of * {@code trustAnchors} are not of type * {@code java.security.cert.TrustAnchor} */ public PKIXBuilderParameters(Set<TrustAnchor> trustAnchors, CertSelector targetConstraints) throws InvalidAlgorithmParameterException { super(trustAnchors); setTargetCertConstraints(targetConstraints); } /** * Creates an instance of {@code PKIXBuilderParameters} that * populates the set of most-trusted CAs from the trusted * certificate entries contained in the specified {@code KeyStore}. * Only keystore entries that contain trusted {@code X509Certificate}s * are considered; all other certificate types are ignored. * * @param keystore a {@code KeyStore} from which the set of * most-trusted CAs will be populated * @param targetConstraints a {@code CertSelector} specifying the * constraints on the target certificate * @throws KeyStoreException if {@code keystore} has not been * initialized * @throws InvalidAlgorithmParameterException if {@code keystore} does * not contain at least one trusted certificate entry * @throws NullPointerException if {@code keystore} is * {@code null} */ public PKIXBuilderParameters(KeyStore keystore, CertSelector targetConstraints) throws KeyStoreException, InvalidAlgorithmParameterException { super(keystore); setTargetCertConstraints(targetConstraints); } /** * Sets the value of the maximum number of non-self-issued intermediate * certificates that may exist in a certification path. A certificate * is self-issued if the DNs that appear in the subject and issuer * fields are identical and are not empty. Note that the last certificate * in a certification path is not an intermediate certificate, and is not * included in this limit. Usually the last certificate is an end entity * certificate, but it can be a CA certificate. A PKIX * {@code CertPathBuilder} instance must not build * paths longer than the length specified. * * <p> A value of 0 implies that the path can only contain * a single certificate. A value of -1 implies that the * path length is unconstrained (i.e. there is no maximum). * The default maximum path length, if not specified, is 5. * Setting a value less than -1 will cause an exception to be thrown. * * <p> If any of the CA certificates contain the * {@code BasicConstraintsExtension}, the value of the * {@code pathLenConstraint} field of the extension overrides * the maximum path length parameter whenever the result is a * certification path of smaller length. * * @param maxPathLength the maximum number of non-self-issued intermediate * certificates that may exist in a certification path * @throws InvalidParameterException if {@code maxPathLength} is set * to a value less than -1 * * @see #getMaxPathLength */ public void setMaxPathLength(int maxPathLength) { if (maxPathLength < -1) { throw new InvalidParameterException("the maximum path " + "length parameter can not be less than -1"); } this.maxPathLength = maxPathLength; } /** * Returns the value of the maximum number of intermediate non-self-issued * certificates that may exist in a certification path. See * the {@link #setMaxPathLength} method for more details. * * @return the maximum number of non-self-issued intermediate certificates * that may exist in a certification path, or -1 if there is no limit * * @see #setMaxPathLength */ public int getMaxPathLength() { return maxPathLength; } /** * Returns a formatted string describing the parameters. * * @return a formatted string describing the parameters */ public String toString() { StringBuilder sb = new StringBuilder(); sb.append("[\n"); sb.append(super.toString()); sb.append(" Maximum Path Length: " + maxPathLength + "\n"); sb.append("]\n"); return sb.toString(); } }