org.apache.hadoop.hbase.util.Strings.java Source code

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Here is the source code for org.apache.hadoop.hbase.util.Strings.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.hadoop.hbase.util;

import org.apache.commons.lang3.StringUtils;
import org.apache.yetus.audience.InterfaceAudience;

/**
 * Utility for Strings.
 */
@InterfaceAudience.Private
public class Strings {
    public final static String DEFAULT_SEPARATOR = "=";
    public final static String DEFAULT_KEYVALUE_SEPARATOR = ", ";

    /**
     * Append to a StringBuilder a key/value.
     * Uses default separators.
     * @param sb StringBuilder to use
     * @param key Key to append.
     * @param value Value to append.
     * @return Passed <code>sb</code> populated with key/value.
     */
    public static StringBuilder appendKeyValue(final StringBuilder sb, final String key, final Object value) {
        return appendKeyValue(sb, key, value, DEFAULT_SEPARATOR, DEFAULT_KEYVALUE_SEPARATOR);
    }

    /**
     * Append to a StringBuilder a key/value.
     * Uses default separators.
     * @param sb StringBuilder to use
     * @param key Key to append.
     * @param value Value to append.
     * @param separator Value to use between key and value.
     * @param keyValueSeparator Value to use between key/value sets.
     * @return Passed <code>sb</code> populated with key/value.
     */
    public static StringBuilder appendKeyValue(final StringBuilder sb, final String key, final Object value,
            final String separator, final String keyValueSeparator) {
        if (sb.length() > 0) {
            sb.append(keyValueSeparator);
        }
        return sb.append(key).append(separator).append(value);
    }

    /**
     * Given a PTR string generated via reverse DNS lookup, return everything
     * except the trailing period. Example for host.example.com., return
     * host.example.com
     * @param dnPtr a domain name pointer (PTR) string.
     * @return Sanitized hostname with last period stripped off.
     *
     */
    public static String domainNamePointerToHostName(String dnPtr) {
        if (dnPtr == null)
            return null;
        return dnPtr.endsWith(".") ? dnPtr.substring(0, dnPtr.length() - 1) : dnPtr;
    }

    /**
     * Push the input string to the right by appending a character before it, usually a space.
     * @param input the string to pad
     * @param padding the character to repeat to the left of the input string
     * @param length the desired total length including the padding
     * @return padding characters + input
     */
    public static String padFront(String input, char padding, int length) {
        if (input.length() > length) {
            throw new IllegalArgumentException("input \"" + input + "\" longer than maxLength=" + length);
        }
        int numPaddingCharacters = length - input.length();
        return StringUtils.repeat(padding, numPaddingCharacters) + input;
    }
}