com.twitter.common.net.InetSocketAddressHelper.java Source code

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Here is the source code for com.twitter.common.net.InetSocketAddressHelper.java

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// =================================================================================================
// Copyright 2011 Twitter, Inc.
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or 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.twitter.common.net;

import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;
import org.apache.commons.lang.StringUtils;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Set;

/**
 * A utility that can parse [host]:[port] pairs or :[port] designators into instances of
 * {@link java.net.InetSocketAddress}. The literal '*' can be specified for port as an alternative
 * to '0' to indicate any local port.
 *
 * @author John Sirois
 */
public final class InetSocketAddressHelper {

    /**
     * A function that uses {@link #parse(String)} to map an endpoint spec to an
     * {@link InetSocketAddress}.
     */
    public static final Function<String, InetSocketAddress> STR_TO_INET = new Function<String, InetSocketAddress>() {
        @Override
        public InetSocketAddress apply(String value) {
            return parse(value);
        }
    };

    /**
     * A function that uses {@link #getLocalAddress(int)} to map a local port number to an
     * {@link InetSocketAddress}.
     * If an {@link UnknownHostException} is thrown, it will be propagated as a
     * {@link RuntimeException}.
     */
    public static final Function<Integer, InetSocketAddress> INT_TO_INET = new Function<Integer, InetSocketAddress>() {
        @Override
        public InetSocketAddress apply(Integer port) {
            try {
                return getLocalAddress(port);
            } catch (UnknownHostException e) {
                throw Throwables.propagate(e);
            }
        }
    };

    public static final Function<InetSocketAddress, String> INET_TO_STR = new Function<InetSocketAddress, String>() {
        @Override
        public String apply(InetSocketAddress addr) {
            return InetSocketAddressHelper.toString(addr);
        }
    };

    /**
     * Attempts to parse an endpoint spec into an InetSocketAddress.
     *
     * @param value the endpoint spec
     * @return a parsed InetSocketAddress
     * @throws NullPointerException     if {@code value} is {@code null}
     * @throws IllegalArgumentException if {@code value} cannot be parsed
     */
    public static InetSocketAddress parse(String value) {
        Preconditions.checkNotNull(value);

        String[] spec = value.split(":", 2);
        if (spec.length != 2) {
            throw new IllegalArgumentException("Invalid socket address spec: " + value);
        }

        String host = spec[0];
        int port = asPort(spec[1]);

        return StringUtils.isEmpty(host) ? new InetSocketAddress(port)
                : InetSocketAddress.createUnresolved(host, port);
    }

    /**
     * Attempts to return a usable String given an InetSocketAddress.
     *
     * @param value the InetSocketAddress.
     * @return the String representation of the InetSocketAddress.
     */
    public static String toString(InetSocketAddress value) {
        Preconditions.checkNotNull(value);
        return value.getHostName() + ":" + value.getPort();
    }

    private static int asPort(String port) {
        if ("*".equals(port)) {
            return 0;
        }
        try {
            return Integer.parseInt(port);
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Invalid port: " + port, e);
        }
    }

    public static InetSocketAddress getLocalAddress(int port) throws UnknownHostException {
        String ipAddress = InetAddress.getLocalHost().getHostAddress();
        return new InetSocketAddress(ipAddress, port);
    }

    private InetSocketAddressHelper() {
        // utility
    }

    /**
     * Converts backend definitions (in host:port form) a set of socket addresses.
     *
     * @param backends Backends to convert.
     * @return Sockets representing the provided backends.
     */
    public static Set<InetSocketAddress> convertToSockets(Iterable<String> backends) {
        return Sets.newHashSet(Iterables.transform(backends, STR_TO_INET));
    }
}