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Diffstat (limited to 'simple/simple-http/src/main/java/org/simpleframework/http/parse/LanguageParser.java')
| -rw-r--r-- | simple/simple-http/src/main/java/org/simpleframework/http/parse/LanguageParser.java | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/simple/simple-http/src/main/java/org/simpleframework/http/parse/LanguageParser.java b/simple/simple-http/src/main/java/org/simpleframework/http/parse/LanguageParser.java new file mode 100644 index 0000000..0a2d215 --- /dev/null +++ b/simple/simple-http/src/main/java/org/simpleframework/http/parse/LanguageParser.java @@ -0,0 +1,156 @@ +/* + * LanguageParser.java February 2001 + * + * Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net> + * + * 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 org.simpleframework.http.parse; + +import java.util.List; +import java.util.Locale; + +/** + * LanguageParser is used to parse the HTTP <code>Accept-Language</code> + * header. This takes in an <code>Accept-Language</code> header and parses + * it according the RFC 2616 BNF for the <code>Accept-Language</code> header. + * This also has the ability to sequence the language tokens in terms of + * the most preferred and the least preferred. + * <p> + * This uses the qvalues outlined by RFC 2616 to order the language tokens + * by preference. Typically the language tokens will not have qvalues with + * the language. However when a language tag has the qvalue parameter then + * this tag will be ordered based on the value of that parameter. A language + * tag without the qvalue parameter is considered to have a qvalue of 1 and + * is ordered accordingly. + * + * @author Niall Gallagher + */ +public class LanguageParser extends ListParser<Locale> { + + /** + * This is used to create a <code>LanguageParser</code> for the + * <code>Accept-Language</code> HTTP header value. This will + * parse a set of language tokens and there parameters. The + * languages will be ordered on preference. This constructor + * will parse the value given using <code>parse(String)</code>. + */ + public LanguageParser() { + super(); + } + + /** + * This is used to create a <code>LanguageParser</code> for the + * <code>Accept-Language</code> HTTP header value. This will + * parse a set of language tokens and there parameters. The + * languages will be ordered on preference. This constructor + * will parse the value given using <code>parse(String)</code>. + * + * @param text value of a <code>Accept-Language</code> header + */ + public LanguageParser(String text) { + super(text); + } + + /** + * This is used to create a <code>LanguageParser</code> for the + * <code>Accept-Language</code> HTTP header value. This will + * parse a set of language tokens and there parameters. The + * languages will be ordered on preference. This constructor + * will parse the value given using <code>parse(String)</code>. + * + * @param list value of a <code>Accept-Language</code> header + */ + public LanguageParser(List<String> list) { + super(list); + } + + /** + * This creates a locale object using an offset and a length. + * The locale is created from the extracted token and the offset + * and length ensure that no leading or trailing whitespace are + * within the created locale object. + * + * @param text this is the text buffer to acquire the value from + * @param start the offset within the array to take characters + * @param len this is the number of characters within the token + */ + @Override + protected Locale create(char[] text, int start, int len){ + String language = language(text, start, len); + String country = country(text, start, len); + + return new Locale(language, country); + } + + /** + * This will extract the primary language tag from the header. + * This token is used to represent the language that will be + * available in the <code>Locale</code> object created. + * + * @param text this is the text buffer to acquire the value from + * @param start the offset within the array to take characters + * @param len this is the number of characters within the token + */ + private String language(char[] text, int start, int len) { + int mark = start; + int size = 0; + + while(start < len) { + char next = text[start]; + + if(terminal(next)) { + return new String(text, mark, size); + } + size++; + start++; + } + return new String(text, mark, len); + } + + /** + * This will extract the primary country tag from the header. + * This token is used to represent the country that will be + * available in the <code>Locale</code> object created. + * + * @param text this is the text buffer to acquire the value from + * @param start the offset within the array to take characters + * @param len this is the number of characters within the token + */ + private String country(char[] text, int start, int len) { + int size = len; + + while(start < len) { + if(text[start++] == '-') { + return new String(text, start, --size); + } + size--; + } + return ""; + } + + /** + * This is used to determine whether the character provided is + * a terminal character. The terminal token is the value that is + * used to separate the country from the language and also any + * character the marks the end of the language token. + * + * @param ch this is the character that is to be evaluated + * + * @return true if the character represents a terminal token + */ + private boolean terminal(char ch) { + return ch ==' ' || ch == '-' || ch == ';'; + } +} |