org.attribyte.util.StringUtil.java Source code

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Here is the source code for org.attribyte.util.StringUtil.java

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/*
 * Copyright 2010 Attribyte, LLC 
 * 
 * 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 org.attribyte.util;

import com.google.common.base.Strings;

import java.text.Normalizer;
import java.security.SecureRandom;

/**
 * Convenience methods for string operations.
 * @author Matt Hamer - Attribyte, LLC.
 */
public class StringUtil {

    /**
     * Shared secure random instance.
     */
    private static final SecureRandom rnd = new SecureRandom();

    /**
     * Determines if a string is non-null, non-empty.
     * @param str The string.
     * @return Does the string have content?
     */
    public static final boolean hasContent(final String str) {
        return str != null && str.length() > 0;
    }

    /**
     * The random character pool.
     */
    private static final char[] rndChars = { '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'a', 'b', 'c', 'd',
            'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
            'W', 'X', 'Y', 'Z' };

    /**
     * Gets a string of random characters.
     * @param numChars The maximum number of characters.
     * @return The random string.
     */
    public static final String randomString(final int numChars) {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < numChars; i++) {
            buf.append(rndChars[rnd.nextInt(rndChars.length)]);
        }

        return buf.toString();
    }

    /**
     * A string equals that allows <tt>null</tt> values
     * and treats them as equivalent to empty strings.
     * @param str1 The first string.
     * @param str2 The second string.
     * @return Are the strings equal?
     */
    @SuppressWarnings({ "StringEquality" })
    public static boolean equals(final String str1, final String str2) {
        return str1 == str2 || Strings.nullToEmpty(str1).equals(Strings.nullToEmpty(str2));
    }

    /**
     * Normalize a string potentially containing Unicode to NFC form.
     * @param str The input string.
     * @return The normalized string.
     */
    public static final String normalizeUnicode(final String str) {
        if (Normalizer.isNormalized(str, Normalizer.Form.NFC)) {
            return str;
        } else {
            return Normalizer.normalize(str, Normalizer.Form.NFC);
        }
    }
}