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	/*
	* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.jvmstat.monitor;

	import java.net.*;

	/**
	* An abstraction that identifies a target host and communications
	* protocol. The HostIdentifier, or hostid, provides a convenient string
	* representation of the information needed to locate and communicate with
	* a target host. The string, based on a {@link URI}, may specify the
	* the communications protocol, host name, and protocol specific information
	* for a target host. The format for a HostIdentifier string is:
	* <pre>
	* [<I>protocol</I>:][[<I>//</I>]<I>hostname</I>][<I>:port</I>][<I>/servername</I>]
	* </pre>
	* There are actually no required components of this string, as a null string
	* is interpreted to mean a local connection to the local host and is equivalent
	* to the string <em>local://localhost</em>. The components of the
	* HostIdentifier are:
	* <ul>
	* <li><p><tt>protocol</tt> - The communications protocol. If omitted,
	* and a hostname is not specified, then default local protocol,
	* <em>local:</em>, is assumed. If the protocol is omitted and a
	* hostname is specified then the default remote protocol,
	* <em>rmi:</em> is assumed.
	* </p></li>
	* <li><p><tt>hostname</tt> - The hostname. If omitted, then
	* <em>localhost</em> is assumed. If the protocol is also omitted,
	* then default local protocol <em>local:</em> is also assumed.
	* If the hostname is not omitted but the protocol is omitted,
	* then the default remote protocol, <em>rmi:</em> is assumed.
	* </p></li>
	* <li><p><tt>port</tt> - The port for the communications protocol.
	* Treatment of the <tt>port</tt> parameter is implementation
	* (protocol) specific. It is unused by the default local protocol,
	* <em>local:</em>. For the default remote protocol, <em>rmi:</em>,
	* <tt>port</tt> indicates the port number of the <em>rmiregistry</em>
	* on the target host and defaults to port 1099.
	* </p></li>
	* <li><p><tt>servername</tt> - The treatment of the Path, Query, and
	* Fragment components of the HostIdentifier are implementation
	* (protocol) dependent. These components are ignored by the
	* default local protocol, <em>local:</em>. For the default remote
	* protocol, <em>rmi</em>, the Path component is interpreted as
	* the name of the RMI remote object. The Query component may
	* contain an access mode specifier <em>?mode=</em> specifying
	* <em>"r"</em> or <em>"rw"</em> access (write access currently
	* ignored). The Fragment part is ignored.
	* </p></li>
	* </ul>
	* <p>
	* All HostIdentifier objects are represented as absolute, hierarchical URIs.
	* The constructors accept relative URIs, but these will generally be
	* transformed into an absolute URI specifying a default protocol. A
	* HostIdentifier differs from a URI in that certain contractions and
	* illicit syntactical constructions are allowed. The following are all
	* valid HostIdentifier strings:
	*
	* <ul>
	* <li><p>&lt null &gt - transformed into "//localhost"</p></li>
	* <li><p>localhost - transformed into "//localhost"</p></li>
	* <li><p>hostname - transformed into "//hostname"</p></li>
	* <li><p>hostname:port - transformed into "//hostname:port"</p></li>
	* <li><p>proto:hostname - transformed into "proto://hostname"</p></li>
	* <li><p>proto:hostname:port - transformed into
	* "proto://hostname:port"</p></li>
	* <li><p>proto://hostname:port</p></li>
	* </ul>
	* </p>
	*
	* @see URI
	* @see VmIdentifier
	*
	* @author Brian Doherty
	* @since 1.5
	*/
	public class HostIdentifier {
	private URI uri;

	/**
	* creates a canonical representation of the uriString. This method
	* performs certain translations depending on the type of URI generated
	* by the string.
	*/
	private URI canonicalize(String uriString) throws URISyntaxException {
	if ((uriString == null) \|\| (uriString.compareTo("localhost") == 0)) {
	uriString = "//localhost";
	return new URI(uriString);
	}

	URI u = new URI(uriString);

	if (u.isAbsolute()) {
	if (u.isOpaque()) {
	/*
	* this code is here to deal with a special case. For ease of
	* use, we'd like to be able to handle the case where the user
	* specifies hostname:port, not requiring the scheme part.
	* This introduces some subtleties.
	* hostname:port - scheme = hostname
	* - schemespecificpart = port
	* - hostname = null
	* - userinfo=null
	* however, someone could also enter scheme:hostname:port and
	* get into this code. the strategy is to consider this
	* syntax illegal and provide some code to defend against it.
	* Basically, we test that the string contains only one ":"
	* and that the ssp is numeric. If we get two colons, we will
	* attempt to insert the "//" after the first colon and then
	* try to create a URI from the resulting string.
	*/
	String scheme = u.getScheme();
	String ssp = u.getSchemeSpecificPart();
	String frag = u.getFragment();
	URI u2 = null;

	int c1index = uriString.indexOf(":");
	int c2index = uriString.lastIndexOf(":");
	if (c2index != c1index) {
	/*
	* this is the scheme:hostname:port case. Attempt to
	* transform this to scheme://hostname:port. If a path
	* part is part of the original strings, it will be
	* included in the SchemeSpecificPart. however, the
	* fragment part must be handled separately.
	*/
	if (frag == null) {
	u2 = new URI(scheme + "://" + ssp);
	} else {
	u2 = new URI(scheme + "://" + ssp + "#" + frag);
	}
	return u2;
	}
	/*
	* here we have the <string>:<string> case, possibly with
	* optional path and fragment components. we assume that
	* the part following the colon is a number. we don't check
	* this condition here as it will get detected later anyway.
	*/
	u2 = new URI("//" + uriString);
	return u2;
	} else {
	return u;
	}
	} else {
	/*
	* This is the case where we were given a hostname followed
	* by a path part, fragment part, or both a path and fragment
	* part. The key here is that no scheme part was specified.
	* For this case, if the scheme specific part does not begin
	* with "//", then we prefix the "//" to the given string and
	* attempt to create a URI from the resulting string.
	*/
	String ssp = u.getSchemeSpecificPart();
	if (ssp.startsWith("//")) {
	return u;
	} else {
	return new URI("//" + uriString);
	}
	}
	}

	/**
	* Create a HostIdentifier instance from a string value.
	*
	* @param uriString a string representing a target host. The syntax of
	* the string must conform to the rules specified in the
	* class documentation.
	*
	* @throws URISyntaxException Thrown when the uriString or its canonical
	* form is poorly formed. This exception may
	* get encapsulated into a MonitorException in
	* a future version.
	*
	*/
	public HostIdentifier(String uriString) throws URISyntaxException {
	uri = canonicalize(uriString);
	}

	/**
	* Create a HostIdentifier instance from component parts of a URI.
	*
	* @param scheme the {@link URI#getScheme} component of a URI.
	* @param authority the {@link URI#getAuthority} component of a URI.
	* @param path the {@link URI#getPath} component of a URI.
	* @param query the {@link URI#getQuery} component of a URI.
	* @param fragment the {@link URI#getFragment} component of a URI.
	*
	* @throws URISyntaxException Thrown when the uriString or its canonical
	* form is poorly formed. This exception may
	* get encapsulated into a MonitorException in
	* a future version.
	* @see URI
	*/
	public HostIdentifier(String scheme, String authority, String path,
	String query, String fragment)
	throws URISyntaxException {
	uri = new URI(scheme, authority, path, query, fragment);
	}

	/**
	* Create a HostIdentifier instance from a VmIdentifier.
	*
	* The necessary components of the VmIdentifier are extracted and
	* reassembled into a HostIdentifier. If a "file:" scheme (protocol)
	* is specified, the the returned HostIdentifier will always be
	* equivalent to HostIdentifier("file://localhost").
	*
	* @param vmid the VmIdentifier use to construct the HostIdentifier.
	*/
	public HostIdentifier(VmIdentifier vmid) {
	/*
	* Extract all components of the VmIdentifier URI except the
	* user-info part of the authority (the lvmid).
	*/
	StringBuilder sb = new StringBuilder();
	String scheme = vmid.getScheme();
	String host = vmid.getHost();
	String authority = vmid.getAuthority();

	// check for 'file:' VmIdentifiers and handled as a special case.
	if ((scheme != null) && (scheme.compareTo("file") == 0)) {
	try {
	uri = new URI("file://localhost");
	} catch (URISyntaxException e) { };
	return;
	}

	if ((host != null) && (host.compareTo(authority) == 0)) {
	/*
	* this condition occurs when the VmIdentifier specifies only
	* the authority (i.e. the lvmid ), and not a host name.
	*/
	host = null;
	}

	if (scheme == null) {
	if (host == null) {
	scheme = "local"; // default local scheme
	} else {
	/*
	* rmi is the default remote scheme. if the VmIdentifier
	* specifies some other protocol, this default is overridden.
	*/
	scheme = "rmi";
	}
	}

	sb.append(scheme).append("://");

	if (host == null) {
	sb.append("localhost"); // default host name
	} else {
	sb.append(host);
	}

	int port = vmid.getPort();
	if (port != -1) {
	sb.append(":").append(port);
	}

	String path = vmid.getPath();
	if ((path != null) && (path.length() != 0)) {
	sb.append(path);
	}

	String query = vmid.getQuery();
	if (query != null) {
	sb.append("?").append(query);
	}

	String frag = vmid.getFragment();
	if (frag != null) {
	sb.append("#").append(frag);
	}

	try {
	uri = new URI(sb.toString());
	} catch (URISyntaxException e) {
	// shouldn't happen, as we were passed a valid VmIdentifier
	throw new RuntimeException("Internal Error", e);
	}
	}

	/**
	* Resolve a VmIdentifier with this HostIdentifier. A VmIdentifier, such
	* as <em>1234</em> or <em>1234@hostname</em> or any other string that
	* omits certain components of the URI string may be valid, but is certainly
	* incomplete. They are missing critical information for identifying the
	* the communications protocol, target host, or other parameters. A
	* VmIdentifier of this form is considered <em>unresolved</em>. This method
	* uses components of the HostIdentifier to resolve the missing components
	* of the VmIdentifier.
	* <p>
	* Specified components of the unresolved VmIdentifier take precedence
	* over their HostIdentifier counterparts. For example, if the VmIdentifier
	* indicates <em>1234@hostname:2099</em> and the HostIdentifier indicates
	* <em>rmi://hostname:1099/</em>, then the resolved VmIdentifier will
	* be <em>rmi://1234@hostname:2099</em>. Any component not explicitly
	* specified or assumed by the HostIdentifier, will remain unresolved in
	* resolved VmIdentifier.
	* <p>
	* A VmIdentifier specifying a <em>file:</em> scheme (protocol), is
	* not changed in any way by this method.
	*
	* @param vmid the unresolved VmIdentifier.
	* @return VmIdentifier - the resolved VmIdentifier. If vmid was resolved
	* on entry to this method, then the returned
	* VmIdentifier will be equal, but not identical, to
	* vmid.
	*/
	public VmIdentifier resolve(VmIdentifier vmid)
	throws URISyntaxException, MonitorException {
	String scheme = vmid.getScheme();
	String host = vmid.getHost();
	String authority = vmid.getAuthority();

	if ((scheme != null) && (scheme.compareTo("file") == 0)) {
	// don't attempt to resolve a file based VmIdentifier.
	return vmid;
	}

	if ((host != null) && (host.compareTo(authority) == 0)) {
	/*
	* this condition occurs when the VmIdentifier specifies only
	* the authority (i.e. an lvmid), and not a host name.
	*/
	host = null;
	}

	if (scheme == null) {
	scheme = getScheme();
	}

	URI nuri = null;

	StringBuffer sb = new StringBuffer();

	sb.append(scheme).append("://");

	String userInfo = vmid.getUserInfo();
	if (userInfo != null) {
	sb.append(userInfo);
	} else {
	sb.append(vmid.getAuthority());
	}

	if (host == null) {
	host = getHost();
	}
	sb.append("@").append(host);

	int port = vmid.getPort();
	if (port == -1) {
	port = getPort();
	}

	if (port != -1) {
	sb.append(":").append(port);
	}

	String path = vmid.getPath();
	if ((path == null) \|\| (path.length() == 0)) {
	path = getPath();
	}

	if ((path != null) && (path.length() > 0)) {
	sb.append(path);
	}

	String query = vmid.getQuery();
	if (query == null) {
	query = getQuery();
	}
	if (query != null) {
	sb.append("?").append(query);
	}

	String fragment = vmid.getFragment();
	if (fragment == null) {
	fragment = getFragment();
	}
	if (fragment != null) {
	sb.append("#").append(fragment);
	}

	String s = sb.toString();
	return new VmIdentifier(s);
	}

	/**
	* Return the Scheme, or protocol, portion of this HostIdentifier.
	*
	* @return String - the scheme for this HostIdentifier.
	* @see URI#getScheme()
	*/
	public String getScheme() {
	return uri.isAbsolute() ? uri.getScheme() : null;
	}

	/**
	* Return the Scheme Specific Part of this HostIdentifier.
	*
	* @return String - the scheme specific part for this HostIdentifier.
	* @see URI#getSchemeSpecificPart()
	*/
	public String getSchemeSpecificPart() {
	return uri.getSchemeSpecificPart();
	}

	/**
	* Return the User Info part of this HostIdentifier.
	*
	* @return String - the user info part for this HostIdentifier.
	* @see URI#getUserInfo()
	*/
	public String getUserInfo() {
	return uri.getUserInfo();
	}

	/**
	* Return the Host part of this HostIdentifier.
	*
	* @return String - the host part for this HostIdentifier, or
	* "localhost" if the URI.getHost() returns null.
	* @see URI#getUserInfo()
	*/
	public String getHost() {
	return (uri.getHost() == null) ? "localhost" : uri.getHost();
	}

	/**
	* Return the Port for of this HostIdentifier.
	*
	* @return String - the port for this HostIdentifier
	* @see URI#getPort()
	*/
	public int getPort() {
	return uri.getPort();
	}

	/**
	* Return the Path part of this HostIdentifier.
	*
	* @return String - the path part for this HostIdentifier.
	* @see URI#getPath()
	*/
	public String getPath() {
	return uri.getPath();
	}

	/**
	* Return the Query part of this HostIdentifier.
	*
	* @return String - the query part for this HostIdentifier.
	* @see URI#getQuery()
	*/
	public String getQuery() {
	return uri.getQuery();
	}

	/**
	* Return the Fragment part of this HostIdentifier.
	*
	* @return String - the fragment part for this HostIdentifier.
	* @see URI#getFragment()
	*/
	public String getFragment() {
	return uri.getFragment();
	}

	/**
	* Return the mode indicated in this HostIdentifier.
	*
	* @return String - the mode string. If no mode is specified, then "r"
	* is returned. otherwise, the specified mode is returned.
	*/
	public String getMode() {
	String query = getQuery();
	if (query != null) {
	String[] queryArgs = query.split("\\+");
	for (int i = 0; i < queryArgs.length; i++) {
	if (queryArgs[i].startsWith("mode=")) {
	int index = queryArgs[i].indexOf('=');
	return queryArgs[i].substring(index+1);
	}
	}
	}
	return "r";
	}

	/**
	* Return the URI associated with the HostIdentifier.
	*
	* @return URI - the URI.
	* @see URI
	*/
	public URI getURI() {
	return uri;
	}

	/**
	* Return the hash code for this HostIdentifier. The hash code is
	* identical to the hash code for the contained URI.
	*
	* @return int - the hashcode.
	* @see URI#hashCode()
	*/
	public int hashCode() {
	return uri.hashCode();
	}

	/**
	* Test for quality with other objects.
	*
	* @param object the object to be test for equality.
	* @return boolean - returns true if the given object is of type
	* HostIdentifier and its URI field is equal to this
	* object's URI field. Otherwise, returns false.
	*
	* @see URI#equals(Object)
	*/
	public boolean equals(Object object) {
	if (object == this) {
	return true;
	}
	if (!(object instanceof HostIdentifier)) {
	return false;
	}
	return uri.equals(((HostIdentifier)object).uri);
	}


	/**
	* Convert to a string representation. Conversion is identical to
	* calling getURI().toString(). This may change in a future release.
	*
	* @return String - a String representation of the HostIdentifier.
	*
	* @see URI#toString()
	*/
	public String toString() {
	return uri.toString();
	}
	}

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