src/java.xml.crypto/share/classes/javax/xml/crypto/KeySelector.java
changeset 47216 71c04702a3d5
parent 25859 3317bb8137f4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.xml.crypto/share/classes/javax/xml/crypto/KeySelector.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2005, 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.
+ */
+/*
+ * $Id: KeySelector.java,v 1.6 2005/05/10 15:47:42 mullan Exp $
+ */
+package javax.xml.crypto;
+
+import java.security.Key;
+import javax.xml.crypto.dsig.keyinfo.KeyInfo;
+import javax.xml.crypto.dsig.keyinfo.RetrievalMethod;
+
+/**
+ * A selector that finds and returns a key using the data contained in a
+ * {@link KeyInfo} object. An example of an implementation of
+ * this class is one that searches a {@link java.security.KeyStore} for
+ * trusted keys that match information contained in a <code>KeyInfo</code>.
+ *
+ * <p>Whether or not the returned key is trusted and the mechanisms
+ * used to determine that is implementation-specific.
+ *
+ * @author Sean Mullan
+ * @author JSR 105 Expert Group
+ * @since 1.6
+ */
+public abstract class KeySelector {
+
+    /**
+     * The purpose of the key that is to be selected.
+     */
+    public static class Purpose {
+
+        private final String name;
+
+        private Purpose(String name)    { this.name = name; }
+
+        /**
+         * Returns a string representation of this purpose ("sign",
+         * "verify", "encrypt", or "decrypt").
+         *
+         * @return a string representation of this purpose
+         */
+        public String toString()        { return name; }
+
+        /**
+         * A key for signing.
+         */
+        public static final Purpose SIGN = new Purpose("sign");
+        /**
+         * A key for verifying.
+         */
+        public static final Purpose VERIFY = new Purpose("verify");
+        /**
+         * A key for encrypting.
+         */
+        public static final Purpose ENCRYPT = new Purpose("encrypt");
+        /**
+         * A key for decrypting.
+         */
+        public static final Purpose DECRYPT = new Purpose("decrypt");
+    }
+
+    /**
+     * Default no-args constructor; intended for invocation by subclasses only.
+     */
+    protected KeySelector() {}
+
+    /**
+     * Attempts to find a key that satisfies the specified constraints.
+     *
+     * @param keyInfo a <code>KeyInfo</code> (may be <code>null</code>)
+     * @param purpose the key's purpose ({@link Purpose#SIGN},
+     *    {@link Purpose#VERIFY}, {@link Purpose#ENCRYPT}, or
+     *    {@link Purpose#DECRYPT})
+     * @param method the algorithm method that this key is to be used for.
+     *    Only keys that are compatible with the algorithm and meet the
+     *    constraints of the specified algorithm should be returned.
+     * @param context an <code>XMLCryptoContext</code> that may contain
+     *    useful information for finding an appropriate key. If this key
+     *    selector supports resolving {@link RetrievalMethod} types, the
+     *    context's <code>baseURI</code> and <code>dereferencer</code>
+     *    parameters (if specified) should be used by the selector to
+     *    resolve and dereference the URI.
+     * @return the result of the key selector
+     * @throws KeySelectorException if an exceptional condition occurs while
+     *    attempting to find a key. Note that an inability to find a key is not
+     *    considered an exception (<code>null</code> should be
+     *    returned in that case). However, an error condition (ex: network
+     *    communications failure) that prevented the <code>KeySelector</code>
+     *    from finding a potential key should be considered an exception.
+     * @throws ClassCastException if the data type of <code>method</code>
+     *    is not supported by this key selector
+     */
+    public abstract KeySelectorResult select(KeyInfo keyInfo, Purpose purpose,
+        AlgorithmMethod method, XMLCryptoContext context)
+        throws KeySelectorException;
+
+    /**
+     * Returns a <code>KeySelector</code> that always selects the specified
+     * key, regardless of the <code>KeyInfo</code> passed to it.
+     *
+     * @param key the sole key to be stored in the key selector
+     * @return a key selector that always selects the specified key
+     * @throws NullPointerException if <code>key</code> is <code>null</code>
+     */
+    public static KeySelector singletonKeySelector(Key key) {
+        return new SingletonKeySelector(key);
+    }
+
+    private static class SingletonKeySelector extends KeySelector {
+        private final Key key;
+
+        SingletonKeySelector(Key key) {
+            if (key == null) {
+                throw new NullPointerException();
+            }
+            this.key = key;
+        }
+
+        public KeySelectorResult select(KeyInfo keyInfo, Purpose purpose,
+            AlgorithmMethod method, XMLCryptoContext context)
+            throws KeySelectorException {
+
+            return new KeySelectorResult() {
+                public Key getKey() {
+                    return key;
+                }
+            };
+        }
+    }
+}