| /* |
| * 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.openjpa.lib.util; |
| |
| /** |
| * Allows for simple regex style testing of strings. The wildcard '.' |
| * is used to represent any single character, while '.*' is used to represent |
| * any series of 0 or more characters. Examples:<br /> |
| * <code> SimpleRegex re = new SimpleRegex("the qu.ck .* dog", true); |
| * boolean matches = re.matches("The quick fox jumped over the lazy dog"); |
| * </code> |
| * |
| */ |
| public class SimpleRegex { |
| |
| private final String expr; |
| private final boolean caseInsensitive; |
| |
| public SimpleRegex(String expr, boolean caseInsensitive) { |
| this.caseInsensitive = caseInsensitive; |
| |
| // If we're case insensitive, toLowerCase the expr. We'll toLowerCase |
| // each target, too, in the matches call. |
| if (caseInsensitive) |
| this.expr = expr.toLowerCase(); |
| else |
| this.expr = expr; |
| } |
| |
| public boolean matches(String target) { |
| // If we're case insensitive, toLowerCase the target |
| if (caseInsensitive) |
| target = target.toLowerCase(); |
| |
| // By default, we are not position independent("mobile"). We only |
| // become position independent once we hit our first ".*". |
| boolean mobile = false; |
| |
| // Find occurrences of ".*" in the expression. |
| int exprPos = 0; |
| int targetPos = 0; |
| while (true) { |
| // Find the next occurrence of ".*" |
| int star = expr.indexOf(".*", exprPos); |
| |
| // If we're at a ".*" now, simply skip it and become position |
| // independent |
| if (star == exprPos) { |
| mobile = true; |
| exprPos += 2; |
| continue; |
| } |
| // If there are no more ".*"s, then we're effectively no longer |
| // position independent(assuming we even were before), since |
| // we must match the end of the string |
| else if (star == -1) { |
| int len = expr.length() - exprPos; |
| |
| // If we're not mobile, then the remainder of the expr and |
| // target must be the same length. If not, then it's not a |
| // match. If we're mobile, then the length doesn't have to |
| // be the same as long as the remainder of the expression |
| // is equal to the end of the target |
| if (!mobile && targetPos != target.length() - len) |
| return false; |
| |
| // In anycase, the remaining length of the target must be |
| // at least as long as the remaining length of the expression. |
| // (We check now to avoid sending a negative start pos to |
| // indexOf) |
| if (target.length() < len) |
| return false; |
| |
| // Match the end of the target to the remainder of the |
| // expression |
| int match = indexOf(target, target.length() - len, exprPos, |
| len, true); |
| if (match != -1) |
| return true; |
| return false; |
| } |
| |
| // Match the fragment of the expression to the target |
| int match = indexOf(target, targetPos, exprPos, |
| star - exprPos, !mobile); |
| if (match == -1) |
| return false; |
| targetPos = match + star - exprPos; |
| exprPos = star + 2; |
| mobile = true; |
| } |
| } |
| |
| /** |
| * Match a section of target to a fragment of the expression. |
| * If we're only to match the beginning of the target, beginOnly |
| * will be true, otherwise we can match anymore in the target(starting |
| * at the targetStart position). A "." in the expression matches any |
| * character. |
| */ |
| private int indexOf(String target, int targetStart, |
| int exprStart, int exprLength, boolean beginOnly) { |
| // Run through the target seeing if there is a match |
| while (target.length() - targetStart >= exprLength) { |
| // Assume success. If there isn't a match we'll break out |
| boolean found = true; |
| for (int i = 0; i < exprLength; i++) { |
| // "." in the expr matches any character in the target |
| if (expr.charAt(exprStart + i) != '.' && |
| expr.charAt(exprStart + i) != |
| target.charAt(targetStart + i)) { |
| found = false; |
| break; |
| } |
| } |
| if (found) |
| return targetStart; |
| |
| // If we're position dependent(beginOnly == true), then don't |
| // continue the search |
| if (beginOnly) |
| return -1; |
| |
| targetStart++; |
| } |
| return -1; |
| } |
| } |