2362N/A * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * A selector that finds and returns a key using the data contained in a 0N/A * {@link KeyInfo} object. An example of an implementation of 0N/A * this class is one that searchs a {@link java.security.KeyStore} for 0N/A * trusted keys that match information contained in a <code>KeyInfo</code>. 0N/A * <p>Whether or not the returned key is trusted and the mechanisms 0N/A * used to determine that is implementation-specific. 0N/A * @author Sean Mullan 0N/A * @author JSR 105 Expert Group 0N/A * The purpose of the key that is to be selected. 0N/A * Returns a string representation of this purpose ("sign", 0N/A * "verify", "encrypt", or "decrypt"). 0N/A * @return a string representation of this purpose 0N/A * A key for signing. 0N/A * A key for verifying. 0N/A * A key for encrypting. 0N/A * A key for decrypting. 0N/A * Default no-args constructor; intended for invocation by subclasses only. 0N/A * Attempts to find a key that satisfies the specified constraints. 0N/A * @param keyInfo a <code>KeyInfo</code> (may be <code>null</code>) 0N/A * @param purpose the key's purpose ({@link Purpose#SIGN}, 0N/A * {@link Purpose#VERIFY}, {@link Purpose#ENCRYPT}, or 0N/A * {@link Purpose#DECRYPT}) 0N/A * @param method the algorithm method that this key is to be used for. 0N/A * Only keys that are compatible with the algorithm and meet the 0N/A * constraints of the specified algorithm should be returned. 0N/A * @param context an <code>XMLCryptoContext</code> that may contain 0N/A * useful information for finding an appropriate key. If this key 0N/A * selector supports resolving {@link RetrievalMethod} types, the 0N/A * context's <code>baseURI</code> and <code>dereferencer</code> 0N/A * parameters (if specified) should be used by the selector to 0N/A * resolve and dereference the URI. 0N/A * @return the result of the key selector 0N/A * @throws KeySelectorException if an exceptional condition occurs while 0N/A * attempting to find a key. Note that an inability to find a key is not 0N/A * considered an exception (<code>null</code> should be 0N/A * returned in that case). However, an error condition (ex: network 0N/A * communications failure) that prevented the <code>KeySelector</code> 0N/A * from finding a potential key should be considered an exception. 0N/A * @throws ClassCastException if the data type of <code>method</code> 0N/A * is not supported by this key selector 0N/A * Returns a <code>KeySelector</code> that always selects the specified 0N/A * key, regardless of the <code>KeyInfo</code> passed to it. 0N/A * @param key the sole key to be stored in the key selector 0N/A * @return a key selector that always selects the specified key 0N/A * @throws NullPointerException if <code>key</code> is <code>null</code>