org.apache.commons.text.matcher.AbstractStringMatcher Maven / Gradle / Ivy
/*
* 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.commons.text.matcher;
import java.util.Arrays;
/**
* A matcher class that can be queried to determine if a character array portion matches.
*
* This class comes complete with various factory methods. If these do not suffice, you can subclass and implement your
* own matcher.
*
* @since 1.3
*/
abstract class AbstractStringMatcher implements StringMatcher {
/**
* Class used to define a character for matching purposes.
*/
static final class CharMatcher extends AbstractStringMatcher {
/** The character to match. */
private final char ch;
/**
* Constructor that creates a matcher that matches a single character.
*
* @param ch
* the character to match
*/
CharMatcher(final char ch) {
super();
this.ch = ch;
}
/**
* Returns whether or not the given character matches.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @param bufferStart
* the first active index in the buffer, valid for buffer
* @param bufferEnd
* the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
@Override
public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
return ch == buffer[pos] ? 1 : 0;
}
}
/**
* Class used to define a set of characters for matching purposes.
*/
static final class CharSetMatcher extends AbstractStringMatcher {
/** The set of characters to match. */
private final char[] chars;
/**
* Constructor that creates a matcher from a character array.
*
* @param chars
* the characters to match, must not be null
*/
CharSetMatcher(final char[] chars) {
super();
this.chars = chars.clone();
Arrays.sort(this.chars);
}
/**
* Returns whether or not the given character matches.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @param bufferStart
* the first active index in the buffer, valid for buffer
* @param bufferEnd
* the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
@Override
public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
return Arrays.binarySearch(chars, buffer[pos]) >= 0 ? 1 : 0;
}
}
/**
* Class used to match no characters.
*/
static final class NoMatcher extends AbstractStringMatcher {
/**
* Constructs a new instance of NoMatcher.
*/
NoMatcher() {
super();
}
/**
* Always returns false.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @param bufferStart
* the first active index in the buffer, valid for buffer
* @param bufferEnd
* the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
@Override
public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
return 0;
}
}
/**
* Class used to define a set of characters for matching purposes.
*/
static final class StringMatcher extends AbstractStringMatcher {
/** The string to match, as a character array. */
private final char[] chars;
/**
* Constructor that creates a matcher from a String.
*
* @param str
* the string to match, must not be null
*/
StringMatcher(final String str) {
super();
chars = str.toCharArray();
}
/**
* Returns whether or not the given text matches the stored string.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @param bufferStart
* the first active index in the buffer, valid for buffer
* @param bufferEnd
* the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
@Override
public int isMatch(final char[] buffer, int pos, final int bufferStart, final int bufferEnd) {
final int len = chars.length;
if (pos + len > bufferEnd) {
return 0;
}
for (int i = 0; i < chars.length; i++, pos++) {
if (chars[i] != buffer[pos]) {
return 0;
}
}
return len;
}
@Override
public String toString() {
return super.toString() + ' ' + Arrays.toString(chars);
}
}
/**
* Class used to match whitespace as per trim().
*/
static final class TrimMatcher extends AbstractStringMatcher {
/**
* The space character.
*/
private static final int SPACE_INT = 32;
/**
* Constructs a new instance of TrimMatcher.
*/
TrimMatcher() {
super();
}
/**
* Returns whether or not the given character matches.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @param bufferStart
* the first active index in the buffer, valid for buffer
* @param bufferEnd
* the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
@Override
public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
return buffer[pos] <= SPACE_INT ? 1 : 0;
}
}
/**
* Constructor.
*/
protected AbstractStringMatcher() {
super();
}
/**
* Returns the number of matching characters, zero for no match.
*
* This method is called to check for a match. The parameter pos represents the current position to be
* checked in the string buffer (a character array which must not be changed). The API guarantees that
* pos is a valid index for buffer.
*
* The matching code may check one character or many. It may check characters preceding pos as well as
* those after.
*
* It must return zero for no match, or a positive number if a match was found. The number indicates the number of
* characters that matched.
*
* @param buffer
* the text content to match against, do not change
* @param pos
* the starting position for the match, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(final char[] buffer, final int pos) {
return isMatch(buffer, pos, 0, buffer.length);
}
}