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- /*
- Copyright (c) 2020 James Ahlborn
-
- 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.healthmarketscience.jackcess.util;
-
- import java.io.IOException;
- import java.util.function.Predicate;
- import java.util.regex.Pattern;
-
- import com.healthmarketscience.jackcess.RuntimeIOException;
- import com.healthmarketscience.jackcess.impl.ColumnImpl;
- import com.healthmarketscience.jackcess.impl.expr.Expressionator;
-
- /**
- * Predicate which tests a column value against a {@link Pattern}. The static
- * factory methods can be used to construct the Pattern from various forms of
- * wildcard pattern syntaxes.
- *
- * This class can be used as a value pattern in the various Cursor search
- * methods, e.g. {@link com.healthmarketscience.jackcess.Cursor#findFirstRow(com.healthmarketscience.jackcess.Column,Object)}.
- *
- * @author James Ahlborn
- */
- public class PatternColumnPredicate implements Predicate<Object>
- {
- private static final int LIKE_REGEX_FLAGS = Pattern.DOTALL;
- private static final int CI_LIKE_REGEX_FLAGS =
- LIKE_REGEX_FLAGS | Pattern.CASE_INSENSITIVE |
- Pattern.UNICODE_CASE;
-
- private final Pattern _pattern;
-
- public PatternColumnPredicate(Pattern pattern) {
- _pattern = pattern;
- }
-
- @Override
- public boolean test(Object value) {
- try {
- // convert column value to string
- CharSequence cs = ColumnImpl.toCharSequence(value);
-
- return _pattern.matcher(cs).matches();
- } catch(IOException e) {
- throw new RuntimeIOException("Could not coerece column value to string", e);
- }
- }
-
- private static Pattern sqlLikeToRegex(
- String value, boolean caseInsensitive)
- {
- StringBuilder sb = new StringBuilder(value.length());
-
- for(int i = 0; i < value.length(); ++i) {
- char c = value.charAt(i);
-
- if(c == '%') {
- sb.append(".*");
- } else if(c == '_') {
- sb.append('.');
- } else if(c == '\\') {
- if(i + 1 < value.length()) {
- appendLiteralChar(sb, value.charAt(++i));
- }
- } else {
- appendLiteralChar(sb, c);
- }
- }
-
- int flags = (caseInsensitive ? CI_LIKE_REGEX_FLAGS : LIKE_REGEX_FLAGS);
- return Pattern.compile(sb.toString(), flags);
- }
-
- private static void appendLiteralChar(StringBuilder sb, char c) {
- if(Expressionator.isRegexSpecialChar(c)) {
- sb.append('\\');
- }
- sb.append(c);
- }
-
- /**
- * @return a PatternColumnPredicate which tests values against the given ms
- * access wildcard pattern (always case insensitive)
- */
- public static PatternColumnPredicate forAccessLike(String pattern) {
- return new PatternColumnPredicate(Expressionator.likePatternToRegex(pattern));
- }
-
- /**
- * @return a PatternColumnPredicate which tests values against the given sql
- * like pattern (supports escape char '\')
- */
- public static PatternColumnPredicate forSqlLike(String pattern) {
- return forSqlLike(pattern, false);
- }
-
- /**
- * @return a PatternColumnPredicate which tests values against the given sql
- * like pattern (supports escape char '\'), optionally case
- * insensitive
- */
- public static PatternColumnPredicate forSqlLike(
- String pattern, boolean caseInsensitive) {
- return new PatternColumnPredicate(sqlLikeToRegex(pattern, caseInsensitive));
- }
-
- /**
- * @return a PatternColumnPredicate which tests values against the given
- * java regex pattern
- */
- public static PatternColumnPredicate forJavaRegex(String pattern) {
- return new PatternColumnPredicate(Pattern.compile(pattern));
- }
- }
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