org.bigmouth.nvwa.zookeeper.addrs.file.FileAddressReader.java Source code

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Here is the source code for org.bigmouth.nvwa.zookeeper.addrs.file.FileAddressReader.java

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/*
 * Copyright 2016 big-mouth.cn
 *
 * The Project 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.bigmouth.nvwa.zookeeper.addrs.file;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;
import org.bigmouth.nvwa.utils.PathUtils;
import org.bigmouth.nvwa.zookeeper.addrs.AddressReader;
import org.bigmouth.nvwa.zookeeper.addrs.ReaderException;

/**
 * ??
 * 
 * <pre>
 * e.g.
 * 
 * ??file:
 * ----- Code -----
 * AddressReader reader = new FileAddressReader("file:/opt/bigmouth/zkaddrs.cfg");
 * System.out.println(reader.read());
 * 
 * ----- Result -----
 * "192.168.1.100:2181,192.168.1.101:2181,192.168.1.102:2181"
 * 
 * ??"%USER_HOME%/zookeeper-address"
 * ----- Code -----
 * AddressReader reader = new FileAddressReader();
 * System.out.println(reader.read());
 * 
 * ----- Result -----
 * "192.168.1.100:2181,192.168.1.101:2181,192.168.1.102:2181"
 * </pre>
 * 
 * @author Allen Hu 2016-3-17
 */
public class FileAddressReader implements AddressReader {

    private static final String PREFIX = "file:";
    public static final String PREFIX_REGX = PREFIX + ".*";
    private static final String USER_HOME = System.getProperty("user.home");
    private static final String DEFAULT_FILENAME = "zookeeper-address";

    private final String path;

    public FileAddressReader() {
        this(null);
    }

    public FileAddressReader(String path) {
        if (StringUtils.isNotBlank(path) && !path.matches(PREFIX_REGX)) {
            throw new RuntimeException("The file path must be begin with '" + PREFIX + "'");
        }
        this.path = path;
    }

    @Override
    public String read() throws ReaderException {
        String filename = path;
        if (StringUtils.isBlank(filename)) {
            filename = StringUtils
                    .join(new String[] { PathUtils.appendEndFileSeparator(USER_HOME), DEFAULT_FILENAME });
        }
        try {
            filename = StringUtils.removeStart(filename, PREFIX);
            String addrs = FileUtils.readFileToString(new File(filename));
            if (StringUtils.isBlank(addrs))
                throw new ReaderException("empty!");
            return StringUtils.trim(addrs);
        } catch (FileNotFoundException e) {
            return null;
        } catch (IOException e) {
            throw new ReaderException(e);
        }
    }
}