diff options
Diffstat (limited to 'bkucommon/src/main/java/at/gv/egiz/bku/binding/IdFactory.java')
-rw-r--r-- | bkucommon/src/main/java/at/gv/egiz/bku/binding/IdFactory.java | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/bkucommon/src/main/java/at/gv/egiz/bku/binding/IdFactory.java b/bkucommon/src/main/java/at/gv/egiz/bku/binding/IdFactory.java new file mode 100644 index 00000000..60bf69a4 --- /dev/null +++ b/bkucommon/src/main/java/at/gv/egiz/bku/binding/IdFactory.java @@ -0,0 +1,106 @@ +/* +* Copyright 2008 Federal Chancellery Austria and +* Graz University of Technology +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License 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 at.gv.egiz.bku.binding;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Creates or converts Ids for BindingProcessors.
+ * @author wbauer
+ *
+ */
+public class IdFactory {
+
+ public static int DEFAULT_NUMBER_OF_BITS = 168;
+
+ private static Log log = LogFactory.getLog(IdFactory.class);
+
+ private static IdFactory instance = new IdFactory();
+
+ private SecureRandom random;
+ private int numberOfBits = DEFAULT_NUMBER_OF_BITS;
+
+ private IdFactory() {
+ try {
+ random = SecureRandom.getInstance("SHA1PRNG");
+ } catch (NoSuchAlgorithmException e) {
+ log.error("Cannot instantiate secure random" + e);
+ }
+ }
+
+ public static IdFactory getInstance() {
+ return instance;
+ }
+
+
+ /**
+ * set the secure random number generator to create secure ids.
+ *
+ * @param random
+ * must not be null
+ */
+ public void setSecureRandom(SecureRandom random) {
+ if (random == null) {
+ throw new NullPointerException("Cannot set secure random to null");
+ }
+ this.random = random;
+ }
+
+ /**
+ * Don't use this method unless you know exactly what you do !
+ * Be sure to use a sufficient large entropy
+ * @param numberOfBits >=1 (although this small entropy does not make sense)
+ */
+ public void setNumberOfBits(int numberOfBits) {
+ if (numberOfBits <1) {
+ throw new IllegalArgumentException("Cannot set number of bits < 1");
+ }
+ this.numberOfBits = numberOfBits;
+ }
+
+ public int getNumberOfBits() {
+ return numberOfBits;
+ }
+
+ /**
+ * Creates a new Id object with the factory's secure RNG and the set number of
+ * bits.
+ *
+ * @return
+ */
+ public Id createId() {
+ return new IdImpl(numberOfBits, random);
+ }
+
+ /**
+ * Creates an Id object for the provided String
+ *
+ * @param idString
+ * may be null in this case the method call creates a new Id.
+ * @return
+ */
+ public Id createId(String idString) {
+ if (idString == null) {
+ return createId();
+ }
+ return new IdImpl(idString);
+ }
+}
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