com.sun.xml.dtdparser.XmlNames Maven / Gradle / Ivy
/*
* Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.xml.dtdparser;
/**
* This class contains static methods used to determine whether identifiers
* may appear in certain roles in XML documents. Such methods are used
* both to parse and to create such documents.
*
* @author David Brownell
* @version 1.1, 00/08/05
*/
public class XmlNames {
private XmlNames() {
}
/**
* Returns true if the value is a legal XML name.
*
* @param value the string being tested
* @return true if the value is a legal XML name
*/
public static boolean isName(String value) {
if (value == null)
return false;
char c = value.charAt(0);
if (!XmlChars.isLetter(c) && c != '_' && c != ':')
return false;
for (int i = 1; i < value.length(); i++)
if (!XmlChars.isNameChar(value.charAt(i)))
return false;
return true;
}
/**
* Returns true if the value is a legal "unqualified" XML name, as
* defined in the XML Namespaces proposed recommendation.
* These are normal XML names, except that they may not contain
* a "colon" character.
*
* @param value the string being tested
* @return true if the value is a legal "unqualified" XML name
*/
public static boolean isUnqualifiedName(String value) {
if (value == null || value.length() == 0)
return false;
char c = value.charAt(0);
if (!XmlChars.isLetter(c) && c != '_')
return false;
for (int i = 1; i < value.length(); i++)
if (!XmlChars.isNCNameChar(value.charAt(i)))
return false;
return true;
}
/**
* Returns true if the value is a legal "qualified" XML name, as defined
* in the XML Namespaces proposed recommendation. Qualified names are
* composed of an optional prefix (an unqualified name), followed by a
* colon, and a required "local part" (an unqualified name). Prefixes are
* declared, and correspond to particular URIs which scope the "local
* part" of the name. (This method cannot check whether the prefix of a
* name has been declared.)
*
* @param value the string being tested
* @return true if the value is a legal "qualified" XML name
*/
public static boolean isQualifiedName(String value) {
if (value == null)
return false;
// [6] QName ::= (Prefix ':')? LocalPart
// [7] Prefix ::= NCName
// [8] LocalPart ::= NCName
int first = value.indexOf(':');
// no Prefix, only check LocalPart
if (first <= 0)
return isUnqualifiedName(value);
// Prefix exists, check everything
int last = value.lastIndexOf(':');
if (last != first)
return false;
return isUnqualifiedName(value.substring(0, first))
&& isUnqualifiedName(value.substring(first + 1));
}
/**
* This method returns true if the identifier is a "name token"
* as defined in the XML specification. Like names, these
* may only contain "name characters"; however, they do not need
* to have letters as their initial characters. Attribute values
* defined to be of type NMTOKEN(S) must satisfy this predicate.
*
* @param token the string being tested
* @return true if the identifier is a "name token"
*/
public static boolean isNmtoken(String token) {
int length = token.length();
for (int i = 0; i < length; i++)
if (!XmlChars.isNameChar(token.charAt(i)))
return false;
return true;
}
/**
* This method returns true if the identifier is a "name token" as
* defined by the XML Namespaces proposed recommendation.
* These are like XML "name tokens" but they may not contain the
* "colon" character.
*
* @param token the string being tested
* @return true if the identifier is a "name token"
* @see #isNmtoken
*/
public static boolean isNCNmtoken(String token) {
return isNmtoken(token) && token.indexOf(':') < 0;
}
}