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package sun.net;

Helper class to map URL "abbreviations" to real URLs. The default implementation supports the following mappings: ftp.mumble.bar/... => ftp://ftp.mumble.bar/... gopher.mumble.bar/... => gopher://gopher.mumble.bar/... other.name.dom/... => http://other.name.dom/... /foo/... => file:/foo/... Full URLs (those including a protocol name) are passed through unchanged. Subclassers can override or extend this behavior to support different or additional canonicalization policies.
Author: Steve Byrne
/** * Helper class to map URL "abbreviations" to real URLs. * The default implementation supports the following mappings: * ftp.mumble.bar/... => ftp://ftp.mumble.bar/... * gopher.mumble.bar/... => gopher://gopher.mumble.bar/... * other.name.dom/... => http://other.name.dom/... * /foo/... => file:/foo/... * * Full URLs (those including a protocol name) are passed through unchanged. * * Subclassers can override or extend this behavior to support different * or additional canonicalization policies. * * @author Steve Byrne */
public class URLCanonicalizer {
Creates the default canonicalizer instance.
/** * Creates the default canonicalizer instance. */
public URLCanonicalizer() { }
Given a possibly abbreviated URL (missing a protocol name, typically), this method's job is to transform that URL into a canonical form, by including a protocol name and additional syntax, if necessary. For a correctly formed URL, this method should just return its argument.
/** * Given a possibly abbreviated URL (missing a protocol name, typically), * this method's job is to transform that URL into a canonical form, * by including a protocol name and additional syntax, if necessary. * * For a correctly formed URL, this method should just return its argument. */
public String canonicalize(String simpleURL) { String resultURL = simpleURL; if (simpleURL.startsWith("ftp.")) { resultURL = "ftp://" + simpleURL; } else if (simpleURL.startsWith("gopher.")) { resultURL = "gopher://" + simpleURL; } else if (simpleURL.startsWith("/")) { resultURL = "file:" + simpleURL; } else if (!hasProtocolName(simpleURL)) { if (isSimpleHostName(simpleURL)) { simpleURL = "www." + simpleURL + ".com"; } resultURL = "http://" + simpleURL; } return resultURL; }
Given a possibly abbreviated URL, this predicate function returns true if it appears that the URL contains a protocol name
/** * Given a possibly abbreviated URL, this predicate function returns * true if it appears that the URL contains a protocol name */
public boolean hasProtocolName(String url) { int index = url.indexOf(':'); if (index <= 0) { // treat ":foo" as not having a protocol spec return false; } for (int i = 0; i < index; i++) { char c = url.charAt(i); // REMIND: this is a guess at legal characters in a protocol -- // need to be verified if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c == '-')) { continue; } // found an illegal character return false; } return true; }
Returns true if the URL is just a single name, no periods or slashes, false otherwise
/** * Returns true if the URL is just a single name, no periods or * slashes, false otherwise **/
protected boolean isSimpleHostName(String url) { for (int i = 0; i < url.length(); i++) { char c = url.charAt(i); // REMIND: this is a guess at legal characters in a protocol -- // need to be verified if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c == '-')) { continue; } // found an illegal character return false; } return true; } }