HADOOP-1566 [hbase] Key-making utility

A    src/java/org/apache/hadoop/hbase/util/Keying.java
A    src/test/org/apache/hadoop/hbase/util/TestKeying.java
    Added.


git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk@553623 13f79535-47bb-0310-9956-ffa450edef68

src/contrib/hbase/CHANGES.txt

@@ -50,3 +50,4 @@ Trunk (unreleased changes)
  30. HADOOP-1531 Add RowFilter to HRegion.HScanner
      Adds a row filtering interface and two implemenentations: A page scanner,
      and a regex row/column-data matcher. (James Kennedy via Stack)
+ 31. HADOOP-1566 Key-making utility

src/contrib/hbase/src/java/org/apache/hadoop/hbase/util/Keying.java

@@ -0,0 +1,112 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.hbase.util;
+
+import java.util.StringTokenizer;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Utility creating hbase friendly keys.
+ * Use fabricating row names or column qualifiers.
+ * <p>TODO: Add createSchemeless key, a key that doesn't care if scheme is
+ * http or https.
+ */
+public class Keying {
+  private static final String SCHEME = "r:";
+  private static final Pattern URI_RE_PARSER =
+    Pattern.compile("^([^:/?#]+://(?:[^/?#@]+@)?)([^:/?#]+)(.*)$");
+
+  /**
+   * Makes a key out of passed URI for use as row name or column qualifier.
+   * 
+   * This method runs transforms on the passed URI so it sits better
+   * as a key (or portion-of-a-key) in hbase.  The <code>host</code> portion of
+   * the URI authority is reversed so subdomains sort under their parent
+   * domain.  The returned String is an opaque URI of an artificial
+   * <code>r:</code> scheme to prevent the result being considered an URI of
+   * the original scheme.  Here is an example of the transform: The url
+   * <code>http://lucene.apache.org/index.html?query=something#middle<code> is
+   * returned as
+   * <code>r:http://org.apache.lucene/index.html?query=something#middle</code>
+   * The transforms are reversible.  No transform is done if passed URI is
+   * not hierarchical.
+   * 
+   * <p>If authority <code>userinfo</code> is present, will mess up the sort
+   * (until we do more work).</p>
+   * 
+   * @param u URL to transform.
+   * @return An opaque URI of artificial 'r' scheme with host portion of URI
+   * authority reversed (if present).
+   * @see #keyToUri(String)
+   * @see <a href="http://www.ietf.org/rfc/rfc2396.txt">RFC2396</a>
+   */
+  public static String createKey(final String u) {
+    if (u.startsWith(SCHEME)) {
+      throw new IllegalArgumentException("Starts with " + SCHEME);
+    }
+    Matcher m = getMatcher(u);
+    if (m == null || !m.matches()) {
+      // If no match, return original String.
+      return u;
+    }
+    return SCHEME + m.group(1) + reverseHostname(m.group(2)) + m.group(3);
+  }
+  
+  /**
+   * Reverse the {@link #createKey(String)} transform.
+   * 
+   * @param s <code>URI</code> made by {@link #createKey(String)}.
+   * @return 'Restored' URI made by reversing the {@link #createKey(String)}
+   * transform.
+   */
+  public static String keyToUri(final String s) {
+    if (!s.startsWith(SCHEME)) {
+      return s;
+    }
+    Matcher m = getMatcher(s.substring(SCHEME.length()));
+    if (m == null || !m.matches()) {
+      // If no match, return original String.
+      return s;
+    }
+    return m.group(1) + reverseHostname(m.group(2)) + m.group(3);
+  }
+  
+  private static Matcher getMatcher(final String u) {
+    if (u == null || u.length() <= 0) {
+      return null;
+    }
+    return URI_RE_PARSER.matcher(u);
+  }
+  
+  private static String reverseHostname(final String hostname) {
+    if (hostname == null) {
+      return "";
+    }
+    StringBuilder sb = new StringBuilder(hostname.length());
+    for (StringTokenizer st = new StringTokenizer(hostname, ".", false);
+        st.hasMoreElements();) {
+      Object next = st.nextElement();
+      if (sb.length() > 0) {
+        sb.insert(0, ".");
+      }
+      sb.insert(0, next);
+    }
+    return sb.toString();
+  }
+}

src/contrib/hbase/src/test/org/apache/hadoop/hbase/util/TestKeying.java

@@ -0,0 +1,51 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.hbase.util;
+
+import junit.framework.TestCase;
+
+public class TestKeying extends TestCase {
+
+  protected void setUp() throws Exception {
+    super.setUp();
+  }
+
+  protected void tearDown() throws Exception {
+    super.tearDown();
+  }
+
+  public void testURI() throws Exception {
+    checkTransform("http://abc:bcd@www.example.com/index.html" +
+      "?query=something#middle");
+    checkTransform("file:///usr/bin/java");
+    checkTransform("dns:www.powerset.com");
+    checkTransform("dns://dns.powerset.com/www.powerset.com");
+    checkTransform("http://one.two.three/index.html");
+    checkTransform("https://one.two.three:9443/index.html");
+    checkTransform("ftp://one.two.three/index.html");
+
+    checkTransform("filename");
+  }
+  
+  private void checkTransform(final String u) {
+    String k = Keying.createKey(u);
+    String uri = Keying.keyToUri(k);
+    System.out.println("Original url " + u + ", Transformed url " + k);
+    assertEquals(u, uri);
+  }
+}