From 3cd9ee863cc00906578345c2869bb307930ef097 Mon Sep 17 00:00:00 2001
From: felmer <felmer>
Date: Mon, 28 Jan 2008 14:06:50 +0000
Subject: [PATCH] password generator added
SVN: 3817
---
.../common/utilities/PasswordGenerator.java | 123 ++++++++++++++++++
1 file changed, 123 insertions(+)
create mode 100644 common/source/java/ch/systemsx/cisd/common/utilities/PasswordGenerator.java
diff --git a/common/source/java/ch/systemsx/cisd/common/utilities/PasswordGenerator.java b/common/source/java/ch/systemsx/cisd/common/utilities/PasswordGenerator.java
new file mode 100644
index 00000000000..77c36ac8026
--- /dev/null
+++ b/common/source/java/ch/systemsx/cisd/common/utilities/PasswordGenerator.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2008 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.utilities;
+
+import java.util.Random;
+
+/**
+ * Generator for human pronounceable passwords
+ *
+ * @author Franz-Josef Elmer
+ */
+public class PasswordGenerator
+{
+ private enum State
+ {
+ DIGIT()
+ {
+ @Override
+ State nextState(Random random)
+ {
+ return random.nextBoolean() ? CONSONANT : VOWEL;
+ }
+
+ @Override
+ String getCharacters()
+ {
+ return "0123456789";
+ }
+ },
+
+ CONSONANT()
+ {
+ @Override
+ State nextState(Random random)
+ {
+ return random.nextBoolean() ? DIGIT : VOWEL;
+ }
+
+ @Override
+ String getCharacters()
+ {
+ return "bdcfghjklmnpqrstvwxzBCDFGHJKLMNPQRSTVWXZ";
+ }
+
+ },
+
+ VOWEL()
+ {
+ @Override
+ State nextState(Random random)
+ {
+ return random.nextBoolean() ? CONSONANT : DIGIT;
+ }
+
+ @Override
+ String getCharacters()
+ {
+ return "aeiouyAEIOUY";
+ }
+ };
+
+ State nextState(Random random)
+ {
+ return this;
+ }
+
+ void appendCharacterTo(StringBuilder builder, Random random)
+ {
+ String characters = getCharacters();
+ builder.append(characters.charAt(random.nextInt(characters.length())));
+ }
+
+ abstract String getCharacters();
+ }
+
+ private final Random random;
+
+ /**
+ * Creates an instance based on the default constructor of {@link Random}.
+ */
+ public PasswordGenerator()
+ {
+ this(new Random());
+ }
+
+ /**
+ * Creates an instance which uses the specified random number generator.
+ */
+ public PasswordGenerator(Random random)
+ {
+ assert random != null : "Unspecified random number generator.";
+ this.random = random;
+ }
+
+ /**
+ * Creates a password of specified length.
+ */
+ public String generatePassword(int length)
+ {
+ State state = State.DIGIT;
+ StringBuilder builder = new StringBuilder();
+ for (int i = 0; i < length; i++)
+ {
+ state = state.nextState(random);
+ state.appendCharacterTo(builder, random);
+ }
+ return builder.toString();
+ }
+}
--
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