libcore/luni/src/main/java/java/net/URLStreamHandler.java - platform/dalvik - Git at Google

 /*
  *  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 java.net;

 import java.io.IOException;

 import org.apache.harmony.luni.util.Msg;
 import org.apache.harmony.luni.util.URLUtil;

 /**
  * The abstract class {@code URLStreamHandler} is the base for all classes which
  * can handle the communication with a URL object over a particular protocol
  * type.
  */
 public abstract class URLStreamHandler {
     /**
      * Establishes a new connection to the resource specified by the URL {@code
      * u}. Since different protocols also have unique ways of connecting, it
      * must be overwritten by the subclass.
      *
      * @param u
      *            the URL to the resource where a connection has to be opened.
      * @return the opened URLConnection to the specified resource.
      * @throws IOException
      *             if an I/O error occurs during opening the connection.
      */
     protected abstract URLConnection openConnection(URL u) throws IOException;

     /**
      * Establishes a new connection to the resource specified by the URL {@code
      * u} using the given {@code proxy}. Since different protocols also have
      * unique ways of connecting, it must be overwritten by the subclass.
      *
      * @param u
      *            the URL to the resource where a connection has to be opened.
      * @param proxy
      *            the proxy that is used to make the connection.
      * @return the opened URLConnection to the specified resource.
      * @throws IOException
      *             if an I/O error occurs during opening the connection.
      * @throws IllegalArgumentException
      *             if any argument is {@code null} or the type of proxy is
      *             wrong.
      * @throws UnsupportedOperationException
      *             if the protocol handler doesn't support this method.
      */
     protected URLConnection openConnection(URL u, Proxy proxy)
             throws IOException {
         throw new UnsupportedOperationException(Msg.getString("K034d")); //$NON-NLS-1$
     }

     /**
      * Parses the clear text URL in {@code str} into a URL object. URL strings
      * generally have the following format:
      * <p>
      * http://www.company.com/java/file1.java#reference
      * <p>
      * The string is parsed in HTTP format. If the protocol has a different URL
      * format this method must be overridden.
      *
      * @param u
      *            the URL to fill in the parsed clear text URL parts.
      * @param str
      *            the URL string that is to be parsed.
      * @param start
      *            the string position from where to begin parsing.
      * @param end
      *            the string position to stop parsing.
      * @see #toExternalForm
      * @see URL
      */
     protected void parseURL(URL u, String str, int start, int end) {
         // For compatibility, refer to Harmony-2941
         if (str.startsWith("//", start) //$NON-NLS-1$
                 && str.indexOf('/', start + 2) == -1
                 && end <= Integer.MIN_VALUE + 1) {
             throw new StringIndexOutOfBoundsException(end - 2 - start);
         }
         if (end < start) {
             if (this != u.strmHandler) {
                 throw new SecurityException();
             }
             return;
         }
         String parseString = ""; //$NON-NLS-1$
         if (start < end) {
             parseString = str.substring(start, end);
         }
         end -= start;
         int fileIdx = 0;

         // Default is to use info from context
         String host = u.getHost();
         int port = u.getPort();
         String ref = u.getRef();
         String file = u.getPath();
         String query = u.getQuery();
         String authority = u.getAuthority();
         String userInfo = u.getUserInfo();

         int refIdx = parseString.indexOf('#', 0);
         if (parseString.startsWith("//")) { //$NON-NLS-1$
             int hostIdx = 2, portIdx = -1;
             port = -1;
             fileIdx = parseString.indexOf('/', hostIdx);
             int questionMarkIndex = parseString.indexOf('?', hostIdx);
             if ((questionMarkIndex != -1)
                     && ((fileIdx == -1) || (fileIdx > questionMarkIndex))) {
                 fileIdx = questionMarkIndex;
             }
             if (fileIdx == -1) {
                 fileIdx = end;
                 // Use default
                 file = ""; //$NON-NLS-1$
             }
             int hostEnd = fileIdx;
             if (refIdx != -1 && refIdx < fileIdx) {
                 hostEnd = refIdx;
             }
             int userIdx = parseString.lastIndexOf('@', hostEnd);
             authority = parseString.substring(hostIdx, hostEnd);
             if (userIdx > -1) {
                 userInfo = parseString.substring(hostIdx, userIdx);
                 hostIdx = userIdx + 1;
             }

             portIdx = parseString.indexOf(':', userIdx == -1 ? hostIdx
                     : userIdx);
             int endOfIPv6Addr = parseString.indexOf(']');
             // if there are square braces, ie. IPv6 address, use last ':'
             if (endOfIPv6Addr != -1) {
                 try {
                     if (parseString.length() > endOfIPv6Addr + 1) {
                         char c = parseString.charAt(endOfIPv6Addr + 1);
                         if (c == ':') {
                             portIdx = endOfIPv6Addr + 1;
                         } else {
                             portIdx = -1;
                         }
                     } else {
                         portIdx = -1;
                     }
                 } catch (Exception e) {
                     // Ignored
                 }
             }

             if (portIdx == -1 || portIdx > fileIdx) {
                 host = parseString.substring(hostIdx, hostEnd);
             } else {
                 host = parseString.substring(hostIdx, portIdx);
                 String portString = parseString.substring(portIdx + 1, hostEnd);
                 if (portString.length() == 0) {
                     port = -1;
                 } else {
                     port = Integer.parseInt(portString);
                 }
             }
         }

         if (refIdx > -1) {
             ref = parseString.substring(refIdx + 1, end);
         }
         int fileEnd = (refIdx == -1 ? end : refIdx);

         int queryIdx = parseString.lastIndexOf('?', fileEnd);
         boolean canonicalize = false;
         if (queryIdx > -1) {
             query = parseString.substring(queryIdx + 1, fileEnd);
             if (queryIdx == 0 && file != null) {
                 if (file.equals("")) { //$NON-NLS-1$
                     file = "/"; //$NON-NLS-1$
                 } else if (file.startsWith("/")) { //$NON-NLS-1$
                     canonicalize = true;
                 }
                 int last = file.lastIndexOf('/') + 1;
                 file = file.substring(0, last);
             }
             fileEnd = queryIdx;
         } else
         // Don't inherit query unless only the ref is changed
         if (refIdx != 0) {
             query = null;
         }

         if (fileIdx > -1) {
             if (fileIdx < end && parseString.charAt(fileIdx) == '/') {
                 file = parseString.substring(fileIdx, fileEnd);
             } else if (fileEnd > fileIdx) {
                 if (file == null) {
                     file = ""; //$NON-NLS-1$
                 } else if (file.equals("")) { //$NON-NLS-1$
                     file = "/"; //$NON-NLS-1$
                 } else if (file.startsWith("/")) { //$NON-NLS-1$
                     canonicalize = true;
                 }
                 int last = file.lastIndexOf('/') + 1;
                 if (last == 0) {
                     file = parseString.substring(fileIdx, fileEnd);
                 } else {
                     file = file.substring(0, last)
                             + parseString.substring(fileIdx, fileEnd);
                 }
             }
         }
         if (file == null) {
             file = ""; //$NON-NLS-1$
         }

         if (host == null) {
             host = ""; //$NON-NLS-1$
         }

         if (canonicalize) {
             // modify file if there's any relative referencing
             file = URLUtil.canonicalizePath(file);
         }

         setURL(u, u.getProtocol(), host, port, authority, userInfo, file,
                 query, ref);
     }

     /**
      * Sets the fields of the URL {@code u} to the values of the supplied
      * arguments.
      *
      * @param u
      *            the non-null URL object to be set.
      * @param protocol
      *            the protocol.
      * @param host
      *            the host name.
      * @param port
      *            the port number.
      * @param file
      *            the file component.
      * @param ref
      *            the reference.
      * @deprecated use setURL(URL, String String, int, String, String, String,
      *             String, String) instead.
      */
     @Deprecated
     protected void setURL(URL u, String protocol, String host, int port,
             String file, String ref) {
         if (this != u.strmHandler) {
             throw new SecurityException();
         }
         u.set(protocol, host, port, file, ref);
     }

     /**
      * Sets the fields of the URL {@code u} to the values of the supplied
      * arguments.
      *
      * @param u
      *            the non-null URL object to be set.
      * @param protocol
      *            the protocol.
      * @param host
      *            the host name.
      * @param port
      *            the port number.
      * @param authority
      *            the authority.
      * @param userInfo
      *            the user info.
      * @param file
      *            the file component.
      * @param query
      *            the query.
      * @param ref
      *            the reference.
      */
     protected void setURL(URL u, String protocol, String host, int port,
             String authority, String userInfo, String file, String query,
             String ref) {
         if (this != u.strmHandler) {
             throw new SecurityException();
         }
         u.set(protocol, host, port, authority, userInfo, file, query, ref);
     }

     /**
      * Returns the clear text representation of a given URL using HTTP format.
      *
      * @param url
      *            the URL object to be converted.
      * @return the clear text representation of the specified URL.
      * @see #parseURL
      * @see URL#toExternalForm()
      */
     protected String toExternalForm(URL url) {
         StringBuilder answer = new StringBuilder();
         answer.append(url.getProtocol());
         answer.append(':');
         String authority = url.getAuthority();
         if (authority != null && authority.length() > 0) {
             answer.append("//"); //$NON-NLS-1$
             answer.append(url.getAuthority());
         }

         String file = url.getFile();
         String ref = url.getRef();
         if (file != null) {
             answer.append(file);
         }
         if (ref != null) {
             answer.append('#');
             answer.append(ref);
         }
         return answer.toString();
     }

     /**
      * Compares two URL objects whether they represent the same URL. Two URLs
      * are equal if they have the same file, host, port, protocol, query, and
      * reference components.
      *
      * @param url1
      *            the first URL to compare.
      * @param url2
      *            the second URL to compare.
      * @return {@code true} if the URLs are the same, {@code false} otherwise.
      * @see #hashCode
      */
     protected boolean equals(URL url1, URL url2) {
         if (!sameFile(url1, url2)) {
             return false;
         }
         String s1 = url1.getRef(), s2 = url2.getRef();
         if (s1 != s2 && (s1 == null || !s1.equals(s2))) {
             return false;
         }
         s1 = url1.getQuery();
         s2 = url2.getQuery();
         return s1 == s2 || (s1 != null && s1.equals(s2));
     }

     /**
      * Returns the default port of the protocol used by the handled URL. The
      * current implementation returns always {@code -1}.
      *
      * @return the appropriate default port number of the protocol.
      */
     protected int getDefaultPort() {
         return -1;
     }

     /**
      * Returns the host address of the given URL.
      *
      * @param url
      *            the URL object where to read the host address from.
      * @return the host address of the specified URL.
      */
     protected InetAddress getHostAddress(URL url) {
         try {
             String host = url.getHost();
             if (host == null || host.length() == 0) {
                 return null;
             }
             return InetAddress.getByName(host);
         } catch (UnknownHostException e) {
             return null;
         }
     }

     /**
      * Returns the hashcode value for the given URL object.
      *
      * @param url
      *            the URL to determine the hashcode.
      * @return the hashcode of the given URL.
      */
     protected int hashCode(URL url) {
         return toExternalForm(url).hashCode();
     }

     /**
      * Compares two URL objects whether they refer to the same host.
      *
      * @param url1
      *            the first URL to be compared.
      * @param url2
      *            the second URL to be compared.
      * @return {@code true} if both URLs refer to the same host, {@code false}
      *         otherwise.
      */
     protected boolean hostsEqual(URL url1, URL url2) {
         String host1 = getHost(url1), host2 = getHost(url2);
         if (host1 == host2 || (host1 != null && host1.equalsIgnoreCase(host2))) {
             return true;
         }
         // Compare host address if the host name is not equal.
         InetAddress address1 = getHostAddress(url1);
         InetAddress address2 = getHostAddress(url2);
         if (address1 != null && address1.equals(address2)) {
             return true;
         }
         return false;
     }

     /**
      * Compares two URL objects whether they refer to the same file. In the
      * comparison included are the URL components protocol, host, port and file.
      *
      * @param url1
      *            the first URL to be compared.
      * @param url2
      *            the second URL to be compared.
      * @return {@code true} if both URLs refer to the same file, {@code false}
      *         otherwise.
      */
     protected boolean sameFile(URL url1, URL url2) {
         String s1 = url1.getProtocol();
         String s2 = url2.getProtocol();
         if (s1 != s2 && (s1 == null || !s1.equals(s2))) {
             return false;
         }

         s1 = url1.getFile();
         s2 = url2.getFile();
         if (s1 != s2 && (s1 == null || !s1.equals(s2))) {
             return false;
         }
         if (!hostsEqual(url1, url2)) {
             return false;
         }
         int p1 = url1.getPort();
         if (p1 == -1) {
             p1 = getDefaultPort();
         }
         int p2 = url2.getPort();
         if (p2 == -1) {
             p2 = getDefaultPort();
         }
         return p1 == p2;
     }

     /*
      * If the URL host is empty while protocal is file, the host is regarded as
      * localhost.
      */
     private static String getHost(URL url) {
         String host = url.getHost();
         if ("file".equals(url.getProtocol()) //$NON-NLS-1$
                 && "".equals(host)) { //$NON-NLS-1$
             host = "localhost"; //$NON-NLS-1$
         }
         return host;
     }
 }
	/*
	* 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 java.net;

	import java.io.IOException;

	import org.apache.harmony.luni.util.Msg;
	import org.apache.harmony.luni.util.URLUtil;

	/**
	* The abstract class {@code URLStreamHandler} is the base for all classes which
	* can handle the communication with a URL object over a particular protocol
	* type.
	*/
	public abstract class URLStreamHandler {
	/**
	* Establishes a new connection to the resource specified by the URL {@code
	* u}. Since different protocols also have unique ways of connecting, it
	* must be overwritten by the subclass.
	*
	* @param u
	* the URL to the resource where a connection has to be opened.
	* @return the opened URLConnection to the specified resource.
	* @throws IOException
	* if an I/O error occurs during opening the connection.
	*/
	protected abstract URLConnection openConnection(URL u) throws IOException;

	/**
	* Establishes a new connection to the resource specified by the URL {@code
	* u} using the given {@code proxy}. Since different protocols also have
	* unique ways of connecting, it must be overwritten by the subclass.
	*
	* @param u
	* the URL to the resource where a connection has to be opened.
	* @param proxy
	* the proxy that is used to make the connection.
	* @return the opened URLConnection to the specified resource.
	* @throws IOException
	* if an I/O error occurs during opening the connection.
	* @throws IllegalArgumentException
	* if any argument is {@code null} or the type of proxy is
	* wrong.
	* @throws UnsupportedOperationException
	* if the protocol handler doesn't support this method.
	*/
	protected URLConnection openConnection(URL u, Proxy proxy)
	throws IOException {
	throw new UnsupportedOperationException(Msg.getString("K034d")); //$NON-NLS-1$
	}

	/**
	* Parses the clear text URL in {@code str} into a URL object. URL strings
	* generally have the following format:
	* <p>
	* http://www.company.com/java/file1.java#reference
	* <p>
	* The string is parsed in HTTP format. If the protocol has a different URL
	* format this method must be overridden.
	*
	* @param u
	* the URL to fill in the parsed clear text URL parts.
	* @param str
	* the URL string that is to be parsed.
	* @param start
	* the string position from where to begin parsing.
	* @param end
	* the string position to stop parsing.
	* @see #toExternalForm
	* @see URL
	*/
	protected void parseURL(URL u, String str, int start, int end) {
	// For compatibility, refer to Harmony-2941
	if (str.startsWith("//", start) //$NON-NLS-1$
	&& str.indexOf('/', start + 2) == -1
	&& end <= Integer.MIN_VALUE + 1) {
	throw new StringIndexOutOfBoundsException(end - 2 - start);
	}
	if (end < start) {
	if (this != u.strmHandler) {
	throw new SecurityException();
	}
	return;
	}
	String parseString = ""; //$NON-NLS-1$
	if (start < end) {
	parseString = str.substring(start, end);
	}
	end -= start;
	int fileIdx = 0;

	// Default is to use info from context
	String host = u.getHost();
	int port = u.getPort();
	String ref = u.getRef();
	String file = u.getPath();
	String query = u.getQuery();
	String authority = u.getAuthority();
	String userInfo = u.getUserInfo();

	int refIdx = parseString.indexOf('#', 0);
	if (parseString.startsWith("//")) { //$NON-NLS-1$
	int hostIdx = 2, portIdx = -1;
	port = -1;
	fileIdx = parseString.indexOf('/', hostIdx);
	int questionMarkIndex = parseString.indexOf('?', hostIdx);
	if ((questionMarkIndex != -1)
	&& ((fileIdx == -1) \|\| (fileIdx > questionMarkIndex))) {
	fileIdx = questionMarkIndex;
	}
	if (fileIdx == -1) {
	fileIdx = end;
	// Use default
	file = ""; //$NON-NLS-1$
	}
	int hostEnd = fileIdx;
	if (refIdx != -1 && refIdx < fileIdx) {
	hostEnd = refIdx;
	}
	int userIdx = parseString.lastIndexOf('@', hostEnd);
	authority = parseString.substring(hostIdx, hostEnd);
	if (userIdx > -1) {
	userInfo = parseString.substring(hostIdx, userIdx);
	hostIdx = userIdx + 1;
	}

	portIdx = parseString.indexOf(':', userIdx == -1 ? hostIdx
	: userIdx);
	int endOfIPv6Addr = parseString.indexOf(']');
	// if there are square braces, ie. IPv6 address, use last ':'
	if (endOfIPv6Addr != -1) {
	try {
	if (parseString.length() > endOfIPv6Addr + 1) {
	char c = parseString.charAt(endOfIPv6Addr + 1);
	if (c == ':') {
	portIdx = endOfIPv6Addr + 1;
	} else {
	portIdx = -1;
	}
	} else {
	portIdx = -1;
	}
	} catch (Exception e) {
	// Ignored
	}
	}

	if (portIdx == -1 \|\| portIdx > fileIdx) {
	host = parseString.substring(hostIdx, hostEnd);
	} else {
	host = parseString.substring(hostIdx, portIdx);
	String portString = parseString.substring(portIdx + 1, hostEnd);
	if (portString.length() == 0) {
	port = -1;
	} else {
	port = Integer.parseInt(portString);
	}
	}
	}

	if (refIdx > -1) {
	ref = parseString.substring(refIdx + 1, end);
	}
	int fileEnd = (refIdx == -1 ? end : refIdx);

	int queryIdx = parseString.lastIndexOf('?', fileEnd);
	boolean canonicalize = false;
	if (queryIdx > -1) {
	query = parseString.substring(queryIdx + 1, fileEnd);
	if (queryIdx == 0 && file != null) {
	if (file.equals("")) { //$NON-NLS-1$
	file = "/"; //$NON-NLS-1$
	} else if (file.startsWith("/")) { //$NON-NLS-1$
	canonicalize = true;
	}
	int last = file.lastIndexOf('/') + 1;
	file = file.substring(0, last);
	}
	fileEnd = queryIdx;
	} else
	// Don't inherit query unless only the ref is changed
	if (refIdx != 0) {
	query = null;
	}

	if (fileIdx > -1) {
	if (fileIdx < end && parseString.charAt(fileIdx) == '/') {
	file = parseString.substring(fileIdx, fileEnd);
	} else if (fileEnd > fileIdx) {
	if (file == null) {
	file = ""; //$NON-NLS-1$
	} else if (file.equals("")) { //$NON-NLS-1$
	file = "/"; //$NON-NLS-1$
	} else if (file.startsWith("/")) { //$NON-NLS-1$
	canonicalize = true;
	}
	int last = file.lastIndexOf('/') + 1;
	if (last == 0) {
	file = parseString.substring(fileIdx, fileEnd);
	} else {
	file = file.substring(0, last)
	+ parseString.substring(fileIdx, fileEnd);
	}
	}
	}
	if (file == null) {
	file = ""; //$NON-NLS-1$
	}

	if (host == null) {
	host = ""; //$NON-NLS-1$
	}

	if (canonicalize) {
	// modify file if there's any relative referencing
	file = URLUtil.canonicalizePath(file);
	}

	setURL(u, u.getProtocol(), host, port, authority, userInfo, file,
	query, ref);
	}

	/**
	* Sets the fields of the URL {@code u} to the values of the supplied
	* arguments.
	*
	* @param u
	* the non-null URL object to be set.
	* @param protocol
	* the protocol.
	* @param host
	* the host name.
	* @param port
	* the port number.
	* @param file
	* the file component.
	* @param ref
	* the reference.
	* @deprecated use setURL(URL, String String, int, String, String, String,
	* String, String) instead.
	*/
	@Deprecated
	protected void setURL(URL u, String protocol, String host, int port,
	String file, String ref) {
	if (this != u.strmHandler) {
	throw new SecurityException();
	}
	u.set(protocol, host, port, file, ref);
	}

	/**
	* Sets the fields of the URL {@code u} to the values of the supplied
	* arguments.
	*
	* @param u
	* the non-null URL object to be set.
	* @param protocol
	* the protocol.
	* @param host
	* the host name.
	* @param port
	* the port number.
	* @param authority
	* the authority.
	* @param userInfo
	* the user info.
	* @param file
	* the file component.
	* @param query
	* the query.
	* @param ref
	* the reference.
	*/
	protected void setURL(URL u, String protocol, String host, int port,
	String authority, String userInfo, String file, String query,
	String ref) {
	if (this != u.strmHandler) {
	throw new SecurityException();
	}
	u.set(protocol, host, port, authority, userInfo, file, query, ref);
	}

	/**
	* Returns the clear text representation of a given URL using HTTP format.
	*
	* @param url
	* the URL object to be converted.
	* @return the clear text representation of the specified URL.
	* @see #parseURL
	* @see URL#toExternalForm()
	*/
	protected String toExternalForm(URL url) {
	StringBuilder answer = new StringBuilder();
	answer.append(url.getProtocol());
	answer.append(':');
	String authority = url.getAuthority();
	if (authority != null && authority.length() > 0) {
	answer.append("//"); //$NON-NLS-1$
	answer.append(url.getAuthority());
	}

	String file = url.getFile();
	String ref = url.getRef();
	if (file != null) {
	answer.append(file);
	}
	if (ref != null) {
	answer.append('#');
	answer.append(ref);
	}
	return answer.toString();
	}

	/**
	* Compares two URL objects whether they represent the same URL. Two URLs
	* are equal if they have the same file, host, port, protocol, query, and
	* reference components.
	*
	* @param url1
	* the first URL to compare.
	* @param url2
	* the second URL to compare.
	* @return {@code true} if the URLs are the same, {@code false} otherwise.
	* @see #hashCode
	*/
	protected boolean equals(URL url1, URL url2) {
	if (!sameFile(url1, url2)) {
	return false;
	}
	String s1 = url1.getRef(), s2 = url2.getRef();
	if (s1 != s2 && (s1 == null \|\| !s1.equals(s2))) {
	return false;
	}
	s1 = url1.getQuery();
	s2 = url2.getQuery();
	return s1 == s2 \|\| (s1 != null && s1.equals(s2));
	}

	/**
	* Returns the default port of the protocol used by the handled URL. The
	* current implementation returns always {@code -1}.
	*
	* @return the appropriate default port number of the protocol.
	*/
	protected int getDefaultPort() {
	return -1;
	}

	/**
	* Returns the host address of the given URL.
	*
	* @param url
	* the URL object where to read the host address from.
	* @return the host address of the specified URL.
	*/
	protected InetAddress getHostAddress(URL url) {
	try {
	String host = url.getHost();
	if (host == null \|\| host.length() == 0) {
	return null;
	}
	return InetAddress.getByName(host);
	} catch (UnknownHostException e) {
	return null;
	}
	}

	/**
	* Returns the hashcode value for the given URL object.
	*
	* @param url
	* the URL to determine the hashcode.
	* @return the hashcode of the given URL.
	*/
	protected int hashCode(URL url) {
	return toExternalForm(url).hashCode();
	}

	/**
	* Compares two URL objects whether they refer to the same host.
	*
	* @param url1
	* the first URL to be compared.
	* @param url2
	* the second URL to be compared.
	* @return {@code true} if both URLs refer to the same host, {@code false}
	* otherwise.
	*/
	protected boolean hostsEqual(URL url1, URL url2) {
	String host1 = getHost(url1), host2 = getHost(url2);
	if (host1 == host2 \|\| (host1 != null && host1.equalsIgnoreCase(host2))) {
	return true;
	}
	// Compare host address if the host name is not equal.
	InetAddress address1 = getHostAddress(url1);
	InetAddress address2 = getHostAddress(url2);
	if (address1 != null && address1.equals(address2)) {
	return true;
	}
	return false;
	}

	/**
	* Compares two URL objects whether they refer to the same file. In the
	* comparison included are the URL components protocol, host, port and file.
	*
	* @param url1
	* the first URL to be compared.
	* @param url2
	* the second URL to be compared.
	* @return {@code true} if both URLs refer to the same file, {@code false}
	* otherwise.
	*/
	protected boolean sameFile(URL url1, URL url2) {
	String s1 = url1.getProtocol();
	String s2 = url2.getProtocol();
	if (s1 != s2 && (s1 == null \|\| !s1.equals(s2))) {
	return false;
	}

	s1 = url1.getFile();
	s2 = url2.getFile();
	if (s1 != s2 && (s1 == null \|\| !s1.equals(s2))) {
	return false;
	}
	if (!hostsEqual(url1, url2)) {
	return false;
	}
	int p1 = url1.getPort();
	if (p1 == -1) {
	p1 = getDefaultPort();
	}
	int p2 = url2.getPort();
	if (p2 == -1) {
	p2 = getDefaultPort();
	}
	return p1 == p2;
	}

	/*
	* If the URL host is empty while protocal is file, the host is regarded as
	* localhost.
	*/
	private static String getHost(URL url) {
	String host = url.getHost();
	if ("file".equals(url.getProtocol()) //$NON-NLS-1$
	&& "".equals(host)) { //$NON-NLS-1$
	host = "localhost"; //$NON-NLS-1$
	}
	return host;
	}
	}