Java String Sub String substring(final String s, int start)

Description

Gets a substring from the specified String avoiding exceptions.

License

Open Source License

Declaration

public static String substring(final String s, int start) 

Method Source Code

//package com.java2s;
/**//from   ww w  .  j  av a  2  s .  c  o m
 * Copyright Sangram Jadhav. All rights reserved.
 *
 * 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.
 */

public class Main {
    /**
     * <p>
     * Gets a substring from the specified String avoiding exceptions.
     * </p>
     *
     * <p>
     * A negative start position can be used to start {@code n} characters from
     * the end of the String.
     * </p>
     *
     * <p>
     * A {@code null} String will return {@code null}. An empty ("") String will
     * return "".
     * </p>
     *
     */
    public static String substring(final String s, int start) {
        if (s == null) {
            return null;
        }

        // handle negatives, which means last n characters
        if (start < 0) {
            start = s.length() + start; // remember start is negative
        }

        if (start < 0) {
            start = 0;
        }
        if (start > s.length()) {
            return "";
        }

        return s.substring(start);
    }

    /**
     * <p>
     * Gets a substring from the specified String avoiding exceptions.
     * </p>
     *
     * <p>
     * A negative start position can be used to start/end {@code n} characters
     * from the end of the String.
     * </p>
     *
     * <p>
     * The returned substring starts with the character in the {@code start}
     * position and ends before the {@code end} position. All position counting
     * is zero-based -- i.e., to start at the beginning of the string use
     * {@code start = 0}. Negative start and end positions can be used to
     * specify offsets relative to the end of the String.
     * </p>
     *
     * <p>
     * If {@code start} is not strictly to the left of {@code end}, "" is
     * returned.
     * </p>
     *
     */
    public static String substring(final String s, int start, int end) {
        if (s == null) {
            return null;
        }

        // handle negatives
        if (end < 0) {
            end = s.length() + end; // remember end is negative
        }
        if (start < 0) {
            start = s.length() + start; // remember start is negative
        }

        // check length next
        if (end > s.length()) {
            end = s.length();
        }

        // if start is greater than end, return ""
        if (start > end) {
            return "";
        }

        if (start < 0) {
            start = 0;
        }
        if (end < 0) {
            end = 0;
        }

        return s.substring(start, end);
    }
}

Related

1. subStrIfNeed(final String str, int num)
2. substring(byte[] array, int start)
3. substring(byte[] src, int start, int len)
4. substring(char[] s, int start, int end)
5. substring(final String pSource, final String pBeginBoundaryString, final String pEndBoundaryString, final int pOffset)
6. substring(final String s, int start, int end)
7. substring(final String s, int startIndex, int endIndex)
8. substring(final String str, int start, int end)
9. substring(final String string, int fromIndex, int toIndex)