| // Copyright (C) 2017 The Android Open Source Project |
| // |
| // 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 com.google.gerrit.server.fixes; |
| |
| import static java.util.Objects.requireNonNull; |
| |
| /** |
| * A modifier of a string. It allows to replace multiple parts of a string by indicating those parts |
| * with indices based on the unmodified string. There is one limitation though: Replacements which |
| * affect lower indices of the string must be specified before replacements for higher indices. |
| */ |
| class StringModifier { |
| |
| private final StringBuilder stringBuilder; |
| |
| private int characterShift = 0; |
| private int previousEndOffset = Integer.MIN_VALUE; |
| |
| StringModifier(String string) { |
| requireNonNull(string, "string must not be null"); |
| stringBuilder = new StringBuilder(string); |
| } |
| |
| /** |
| * Replaces part of the string with another content. When called multiple times, the calls must be |
| * ordered according to increasing start indices. Overlapping replacement regions aren't |
| * supported. |
| * |
| * @param startIndex the beginning index in the unmodified string (inclusive) |
| * @param endIndex the ending index in the unmodified string (exclusive) |
| * @param replacement the string which should be used instead of the original content |
| * @throws StringIndexOutOfBoundsException if the start index is smaller than the end index of a |
| * previous call of this method |
| */ |
| public void replace(int startIndex, int endIndex, String replacement) { |
| requireNonNull(replacement, "replacement string must not be null"); |
| if (previousEndOffset > startIndex) { |
| throw new StringIndexOutOfBoundsException( |
| String.format( |
| "Not supported to replace the content starting at index %s after previous " |
| + "replacement which ended at index %s", |
| startIndex, previousEndOffset)); |
| } |
| int shiftedStartIndex = startIndex + characterShift; |
| int shiftedEndIndex = endIndex + characterShift; |
| if (shiftedEndIndex > stringBuilder.length()) { |
| throw new StringIndexOutOfBoundsException( |
| String.format("end %s > length %s", shiftedEndIndex, stringBuilder.length())); |
| } |
| stringBuilder.replace(shiftedStartIndex, shiftedEndIndex, replacement); |
| |
| int replacedContentLength = endIndex - startIndex; |
| characterShift += replacement.length() - replacedContentLength; |
| previousEndOffset = endIndex; |
| } |
| |
| /** |
| * Returns the modified string including all specified replacements. |
| * |
| * @return the modified string |
| */ |
| public String getResult() { |
| return stringBuilder.toString(); |
| } |
| } |