PatternBuilder.java

/**
 * 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.cxf.transport.http;

import java.util.regex.Pattern;

/**
 * Convert a "nonProxyHosts" formatted String into a usable regular expression usable in {@code Pattern}.
 */
public final class PatternBuilder {

    /**
     * Default empty constructor fot utility class.
     */
    private PatternBuilder() { }

    /**
     * Builds a {@code Pattern} from the given String argument.
     * @param value pattern like expression
     * @return a usable {@code Pattern}.
     */
    public static Pattern build(final String value) {

        // Here is a usual nonProxyHosts value:
        // localhost|www.google.*|*.apache.org
        // '|' are separator for 'or' group
        // '.' are real dots
        // '*' means any char (length >= 0)

        // So we need to convert that value a little bit to make it a real regular expression suited for Java

        String regexp = value.replace(".", "\\.");
        regexp = regexp.replace("*", ".*");

        return Pattern.compile(regexp);
    }
}