org.springframework.core.util.AntPathStringMatcher.java Source code

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Here is the source code for org.springframework.core.util.AntPathStringMatcher.java

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package org.springframework.core.util;/*
                                      * Copyright 2002-2009 the original author or authors.
                                      *
                                      * 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.
                                      */

import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Package-protected helper class for {@link AntPathMatcher}. Tests whether or not a string matches against a pattern
 * using a regular expression.
 * <p/>
 * <p>The pattern may contain special characters: '*' means zero or more characters; '?' means one and only one
 * character; '{' and '}' indicate a URI template pattern.
 *
 * @author Arjen Poutsma
 * @since 3.0
 */
class AntPathStringMatcher {

    private static final Pattern GLOB_PATTERN = Pattern.compile("\\?|\\*|\\{([^/]+?)\\}");

    private static final String DEFAULT_VARIABLE_PATTERN = "(.*)";

    private final Pattern pattern;

    private String str;

    private final List<String> variableNames = new LinkedList<String>();

    private final Map<String, String> uriTemplateVariables;

    /**
     * Construct a new instance of the <code>AntPatchStringMatcher</code>.
     */
    AntPathStringMatcher(final String pattern, final String str, final Map<String, String> uriTemplateVariables) {
        this.str = str;
        this.uriTemplateVariables = uriTemplateVariables;
        this.pattern = createPattern(pattern);
    }

    private Pattern createPattern(final String pattern) {
        StringBuilder patternBuilder = new StringBuilder();
        Matcher m = GLOB_PATTERN.matcher(pattern);
        int end = 0;
        while (m.find()) {
            patternBuilder.append(quote(pattern, end, m.start()));
            String match = m.group();
            if ("?".equals(match)) {
                patternBuilder.append('.');
            } else if ("*".equals(match)) {
                patternBuilder.append(".*");
            } else if (match.startsWith("{") && match.endsWith("}")) {
                int colonIdx = match.indexOf(':');
                if (colonIdx == -1) {
                    patternBuilder.append(DEFAULT_VARIABLE_PATTERN);
                    variableNames.add(m.group(1));
                } else {
                    String variablePattern = match.substring(colonIdx + 1, match.length() - 1);
                    patternBuilder.append('(');
                    patternBuilder.append(variablePattern);
                    patternBuilder.append(')');
                    String variableName = match.substring(1, colonIdx);
                    variableNames.add(variableName);
                }
            }
            end = m.end();
        }
        patternBuilder.append(quote(pattern, end, pattern.length()));
        return Pattern.compile(patternBuilder.toString());
    }

    private String quote(final String s, final int start, final int end) {
        if (start == end) {
            return "";
        }
        return Pattern.quote(s.substring(start, end));
    }

    /**
     * Main entry point.
     *
     * @return <code>true</code> if the string matches against the pattern, or <code>false</code> otherwise.
     */
    public boolean matchStrings() {
        Matcher matcher = pattern.matcher(str);
        if (matcher.matches()) {
            if (uriTemplateVariables != null) {
                for (int i = 1; i <= matcher.groupCount(); i++) {
                    String name = this.variableNames.get(i - 1);
                    String value = matcher.group(i);
                    uriTemplateVariables.put(name, value);
                }
            }
            return true;
        } else {
            return false;
        }
    }

}