/*
* Copyright (C) 2011 The Guava 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.
*/
package com.google.common.net;
import com.google.common.annotations.Beta;
import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* HostAndPort performs high-level segmenting of host:port strings.
*
* <p>Example usage:
* <pre>
* HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
* .withDefaultPort(80)
* .requireBracketsForIPv6();
* hp.getHostText(); // returns "2001:db8::1"
* hp.getPort(); // returns 80
* hp.toString(); // returns "[2001:db8::1]:80"
* </pre>
*
* <p>Here are some examples of recognized formats:
* <ul>
* <li>example.com
* <li>example.com:80
* <li>192.0.2.1
* <li>192.0.2.1:80
* <li>[2001:db8::1] - {@link #getHostText()} omits brackets
* <li>[2001:db8::1]:80 - {@link #getHostText()} omits brackets
* <li>2001:db8::1 - Use {@link #requireBracketsForIPv6()} to prohibit this
* </ul>
*
* <p>Note that this is not an exhaustive list, because these methods are only
* concerned with brackets, colons, and port numbers. Full validation of the
* host field (if desired) is the caller's responsibility.
*
* @author Paul Marks
* @since 10.0
*/
@Beta
public final class HostAndPort {
/** Magic value indicating the absence of a port number. */
private static final int NO_PORT = -1;
/** Hostname, IPv4/IPv6 literal, or unvalidated nonsense. */
private final String host;
/** Validated port number in the range [0..65535], or NO_PORT */
private final int port;
/** True if the parsed host has colons, but no surrounding brackets. */
private final boolean hasBracketlessColons;
private HostAndPort(String host, int port, boolean hasBracketlessColons) {
this.host = host;
this.port = port;
this.hasBracketlessColons = hasBracketlessColons;
}
/**
* Returns the portion of this {@code HostAndPort} instance that should
* represent the hostname or IPv4/IPv6 literal.
*
* A successful parse does not imply any degree of sanity in this field.
* For additional validation, see the {@link HostSpecifier} class.
*/
public String getHostText() {
return host;
}
/** Return true if this instance has a defined port. */
public boolean hasPort() {
return port >= 0;
}
/**
* Get the current port number, failing if no port is defined.
*
* @return a validated port number, in the range [0..65535]
* @throws IllegalStateException if no port is defined. You can use
* {@link #withDefaultPort(int)} to prevent this from occurring.
*/
public int getPort() {
Preconditions.checkState(hasPort());
return port;
}
/**
* Returns the current port number, with a default if no port is defined.
*/
public int getPortOrDefault(int defaultPort) {
return hasPort() ? port : defaultPort;
}
/**
* Build a HostAndPort instance from separate host and port values.
*
* <p>Note: Non-bracketed IPv6 literals are allowed.
* Use {@link #requireBracketsForIPv6()} to prohibit these.
*
* @param host the host string to parse. Must not contain a port number.
* @param port a port number from [0..65535]
* @return if parsing was successful, a populated HostAndPort object.
* @throws IllegalArgumentException if {@code host} contains a port number,
* or {@code port} is out of range.
*/
public static HostAndPort fromParts(String host, int port) {
Preconditions.checkArgument(isValidPort(port));
HostAndPort parsedHost = fromString(host);
Preconditions.checkArgument(!parsedHost.hasPort());
return new HostAndPort(parsedHost.host, port, parsedHost.hasBracketlessColons);
}
private static final Pattern BRACKET_PATTERN = Pattern.compile("^\\[(.*:.*)\\](?::(\\d*))?$");
/**
* Split a freeform string into a host and port, without strict validation.
*
* Note that the host-only formats will leave the port field undefined. You
* can use {@link #withDefaultPort(int)} to patch in a default value.
*
* @param hostPortString the input string to parse.
* @return if parsing was successful, a populated HostAndPort object.
* @throws IllegalArgumentException if nothing meaningful could be parsed.
*/
public static HostAndPort fromString(String hostPortString) {
Preconditions.checkNotNull(hostPortString);
String host;
String portString = null;
boolean hasBracketlessColons = false;
if (hostPortString.startsWith("[")) {
// Parse a bracketed host, typically an IPv6 literal.
Matcher matcher = BRACKET_PATTERN.matcher(hostPortString);
Preconditions.checkArgument(matcher.matches(),
"Invalid bracketed host/port: %s", hostPortString);
host = matcher.group(1);
portString = matcher.group(2); // could be null
} else {
int colonPos = hostPortString.indexOf(':');
if (colonPos >= 0 && hostPortString.indexOf(':', colonPos + 1) == -1) {
// Exactly 1 colon. Split into host:port.
host = hostPortString.substring(0, colonPos);
portString = hostPortString.substring(colonPos + 1);
} else {
// 0 or 2+ colons. Bare hostname or IPv6 literal.
host = hostPortString;
hasBracketlessColons = (colonPos >= 0);
}
}
int port = NO_PORT;
if (portString != null) {
// Try to parse the whole port string as a number.
try {
port = Integer.parseInt(portString);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Unparseable port number: " + hostPortString);
}
Preconditions.checkArgument(isValidPort(port),
"Port number out of range: %s", hostPortString);
}
return new HostAndPort(host, port, hasBracketlessColons);
}
/**
* Provide a default port if the parsed string contained only a host.
*
* You can chain this after {@link #fromString(String)} to include a port in
* case the port was omitted from the input string. If a port was already
* provided, then this method is a no-op.
*
* @param defaultPort a port number, from [0..65535]
* @return a HostAndPort instance, guaranteed to have a defined port.
*/
public HostAndPort withDefaultPort(int defaultPort) {
Preconditions.checkArgument(isValidPort(defaultPort));
if (hasPort() || port == defaultPort) {
return this;
}
return new HostAndPort(host, defaultPort, hasBracketlessColons);
}
/**
* Generate an error if the host might be a non-bracketed IPv6 literal.
*
* <p>URI formatting requires that IPv6 literals be surrounded by brackets,
* like "[2001:db8::1]". Chain this call after {@link #fromString(String)}
* to increase the strictness of the parser, and disallow IPv6 literals
* that don't contain these brackets.
*
* <p>Note that this parser identifies IPv6 literals solely based on the
* presence of a colon. To perform actual validation of IP addresses, see
* the {@link InetAddresses#forString(String)} method.
*
* @return {@code this}, to enable chaining of calls.
* @throws IllegalArgumentException if bracketless IPv6 is detected.
*/
public HostAndPort requireBracketsForIPv6() {
Preconditions.checkArgument(!hasBracketlessColons,
"Possible bracketless IPv6 literal: %s", host);
return this;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other instanceof HostAndPort) {
HostAndPort that = (HostAndPort) other;
return Objects.equal(this.host, that.host)
&& this.port == that.port
&& this.hasBracketlessColons == that.hasBracketlessColons;
}
return false;
}
@Override
public int hashCode() {
return Objects.hashCode(host, port, hasBracketlessColons);
}
/** Rebuild the host:port string, including brackets if necessary. */
@Override
public String toString() {
StringBuilder builder = new StringBuilder(host.length() + 7);
if (host.indexOf(':') >= 0) {
builder.append('[').append(host).append(']');
} else {
builder.append(host);
}
if (hasPort()) {
builder.append(':').append(port);
}
return builder.toString();
}
/** Return true for valid port numbers. */
private static boolean isValidPort(int port) {
return port >= 0 && port <= 65535;
}
}
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