org.apache.nutch.util.TableUtil.java Source code

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Here is the source code for org.apache.nutch.util.TableUtil.java

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/*******************************************************************************
 * 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.nutch.util;

import org.apache.commons.lang.StringUtils;

import java.net.MalformedURLException;
import java.net.URL;
import java.nio.ByteBuffer;

public class TableUtil {

    public static final ByteBuffer YES_VAL = ByteBuffer.wrap(new byte[] { 'y' });

    /**
     * Reverses a url's domain. This form is better for storing in hbase. Because
     * scans within the same domain are faster.
     * <p>
     * E.g. "http://bar.foo.com:8983/to/index.html?a=b" becomes
     * "com.foo.bar:8983:http/to/index.html?a=b".
     * 
     * @param urlString
     *          url to be reversed
     * @return Reversed url
     * @throws MalformedURLException
     */
    public static String reverseUrl(String urlString) throws MalformedURLException {
        return reverseUrl(new URL(urlString));
    }

    /**
     * Reverses a url's domain. This form is better for storing in hbase. Because
     * scans within the same domain are faster.
     * <p>
     * E.g. "http://bar.foo.com:8983/to/index.html?a=b" becomes
     * "com.foo.bar:http:8983/to/index.html?a=b".
     * 
     * @param url
     *          url to be reversed
     * @return Reversed url
     */
    public static String reverseUrl(URL url) {
        String host = url.getHost();
        String file = url.getFile();
        String protocol = url.getProtocol();
        int port = url.getPort();

        StringBuilder buf = new StringBuilder();

        /* reverse host */
        reverseAppendSplits(host, buf);

        /* add protocol */
        buf.append(':');
        buf.append(protocol);

        /* add port if necessary */
        if (port != -1) {
            buf.append(':');
            buf.append(port);
        }

        /* add path */
        if (file.length() > 0 && '/' != file.charAt(0)) {
            buf.append('/');
        }
        buf.append(file);

        return buf.toString();
    }

    public static String unreverseUrl(String reversedUrl) {
        StringBuilder buf = new StringBuilder(reversedUrl.length() + 2);

        int pathBegin = reversedUrl.indexOf('/');
        if (pathBegin == -1)
            pathBegin = reversedUrl.length();
        String sub = reversedUrl.substring(0, pathBegin);

        String[] splits = StringUtils.splitPreserveAllTokens(sub, ':'); // {<reversed
                                                                        // host>,
                                                                        // <port>,
                                                                        // <protocol>}

        buf.append(splits[1]); // add protocol
        buf.append("://");
        reverseAppendSplits(splits[0], buf); // splits[0] is reversed
        // host
        if (splits.length == 3) { // has a port
            buf.append(':');
            buf.append(splits[2]);
        }
        buf.append(reversedUrl.substring(pathBegin));
        return buf.toString();
    }

    /**
     * Given a reversed url, returns the reversed host E.g
     * "com.foo.bar:http:8983/to/index.html?a=b" -&gt; "com.foo.bar"
     * 
     * @param reversedUrl
     *          Reversed url
     * @return Reversed host
     */
    public static String getReversedHost(String reversedUrl) {
        return reversedUrl.substring(0, reversedUrl.indexOf(':'));
    }

    private static void reverseAppendSplits(String string, StringBuilder buf) {
        String[] splits = StringUtils.split(string, '.');
        if (splits.length > 0) {
            for (int i = splits.length - 1; i > 0; i--) {
                buf.append(splits[i]);
                buf.append('.');
            }
            buf.append(splits[0]);
        } else {
            buf.append(string);
        }
    }

    public static String reverseHost(String hostName) {
        StringBuilder buf = new StringBuilder();
        reverseAppendSplits(hostName, buf);
        return buf.toString();

    }

    public static String unreverseHost(String reversedHostName) {
        return reverseHost(reversedHostName); // Reversible
    }

    /**
     * Convert given Utf8 instance to String and and cleans out any offending ""
     * from the String.
     * 
     * 
     * @param utf8
     *          Utf8 object
     * @return string-ifed Utf8 object or null if Utf8 instance is null
     */
    public static String toString(CharSequence utf8) {
        return (utf8 == null ? null : StringUtil.cleanField(utf8.toString()));
    }

}