/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0/module-main/src/main/java/org/apache/http/message/BasicHeaderValueParser.java $
* $Revision: 744527 $
* $Date: 2009-02-14 18:06:25 +0100 (Sat, 14 Feb 2009) $
*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.message;
import java.util.List;
import java.util.ArrayList;
import org.apache.http.HeaderElement;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.CharArrayBuffer;
/**
* Basic implementation for parsing header values into elements.
* Instances of this class are stateless and thread-safe.
* Derived classes are expected to maintain these properties.
*
*
*
* <!-- empty lines above to avoid 'svn diff' context problems -->
* @version $Revision: 744527 $
*
* @since 4.0
*/
public class BasicHeaderValueParser implements HeaderValueParser {
/**
* A default instance of this class, for use as default or fallback.
* Note that {@link BasicHeaderValueParser} is not a singleton, there
* can be many instances of the class itself and of derived classes.
* The instance here provides non-customized, default behavior.
*/
public final static
BasicHeaderValueParser DEFAULT = new BasicHeaderValueParser();
private final static char PARAM_DELIMITER = ';';
private final static char ELEM_DELIMITER = ',';
private final static char[] ALL_DELIMITERS = new char[] {
PARAM_DELIMITER,
ELEM_DELIMITER
};
// public default constructor
/**
* Parses elements with the given parser.
*
* @param value the header value to parse
* @param parser the parser to use, or <code>null</code> for default
*
* @return array holding the header elements, never <code>null</code>
*/
public final static
HeaderElement[] parseElements(final String value,
HeaderValueParser parser)
throws ParseException {
if (value == null) {
throw new IllegalArgumentException
("Value to parse may not be null");
}
if (parser == null)
parser = BasicHeaderValueParser.DEFAULT;
CharArrayBuffer buffer = new CharArrayBuffer(value.length());
buffer.append(value);
ParserCursor cursor = new ParserCursor(0, value.length());
return parser.parseElements(buffer, cursor);
}
// non-javadoc, see interface HeaderValueParser
public HeaderElement[] parseElements(final CharArrayBuffer buffer,
final ParserCursor cursor) {
if (buffer == null) {
throw new IllegalArgumentException("Char array buffer may not be null");
}
if (cursor == null) {
throw new IllegalArgumentException("Parser cursor may not be null");
}
List elements = new ArrayList();
while (!cursor.atEnd()) {
HeaderElement element = parseHeaderElement(buffer, cursor);
if (!(element.getName().length() == 0 && element.getValue() == null)) {
elements.add(element);
}
}
return (HeaderElement[])
elements.toArray(new HeaderElement[elements.size()]);
}
/**
* Parses an element with the given parser.
*
* @param value the header element to parse
* @param parser the parser to use, or <code>null</code> for default
*
* @return the parsed header element
*/
public final static
HeaderElement parseHeaderElement(final String value,
HeaderValueParser parser)
throws ParseException {
if (value == null) {
throw new IllegalArgumentException
("Value to parse may not be null");
}
if (parser == null)
parser = BasicHeaderValueParser.DEFAULT;
CharArrayBuffer buffer = new CharArrayBuffer(value.length());
buffer.append(value);
ParserCursor cursor = new ParserCursor(0, value.length());
return parser.parseHeaderElement(buffer, cursor);
}
// non-javadoc, see interface HeaderValueParser
public HeaderElement parseHeaderElement(final CharArrayBuffer buffer,
final ParserCursor cursor) {
if (buffer == null) {
throw new IllegalArgumentException("Char array buffer may not be null");
}
if (cursor == null) {
throw new IllegalArgumentException("Parser cursor may not be null");
}
NameValuePair nvp = parseNameValuePair(buffer, cursor);
NameValuePair[] params = null;
if (!cursor.atEnd()) {
char ch = buffer.charAt(cursor.getPos() - 1);
if (ch != ELEM_DELIMITER) {
params = parseParameters(buffer, cursor);
}
}
return createHeaderElement(nvp.getName(), nvp.getValue(), params);
}
/**
* Creates a header element.
* Called from {@link #parseHeaderElement}.
*
* @return a header element representing the argument
*/
protected HeaderElement createHeaderElement(
final String name,
final String value,
final NameValuePair[] params) {
return new BasicHeaderElement(name, value, params);
}
/**
* Parses parameters with the given parser.
*
* @param value the parameter list to parse
* @param parser the parser to use, or <code>null</code> for default
*
* @return array holding the parameters, never <code>null</code>
*/
public final static
NameValuePair[] parseParameters(final String value,
HeaderValueParser parser)
throws ParseException {
if (value == null) {
throw new IllegalArgumentException
("Value to parse may not be null");
}
if (parser == null)
parser = BasicHeaderValueParser.DEFAULT;
CharArrayBuffer buffer = new CharArrayBuffer(value.length());
buffer.append(value);
ParserCursor cursor = new ParserCursor(0, value.length());
return parser.parseParameters(buffer, cursor);
}
// non-javadoc, see interface HeaderValueParser
public NameValuePair[] parseParameters(final CharArrayBuffer buffer,
final ParserCursor cursor) {
if (buffer == null) {
throw new IllegalArgumentException("Char array buffer may not be null");
}
if (cursor == null) {
throw new IllegalArgumentException("Parser cursor may not be null");
}
int pos = cursor.getPos();
int indexTo = cursor.getUpperBound();
while (pos < indexTo) {
char ch = buffer.charAt(pos);
if (HTTP.isWhitespace(ch)) {
pos++;
} else {
break;
}
}
cursor.updatePos(pos);
if (cursor.atEnd()) {
return new NameValuePair[] {};
}
List params = new ArrayList();
while (!cursor.atEnd()) {
NameValuePair param = parseNameValuePair(buffer, cursor);
params.add(param);
char ch = buffer.charAt(cursor.getPos() - 1);
if (ch == ELEM_DELIMITER) {
break;
}
}
return (NameValuePair[])
params.toArray(new NameValuePair[params.size()]);
}
/**
* Parses a name-value-pair with the given parser.
*
* @param value the NVP to parse
* @param parser the parser to use, or <code>null</code> for default
*
* @return the parsed name-value pair
*/
public final static
NameValuePair parseNameValuePair(final String value,
HeaderValueParser parser)
throws ParseException {
if (value == null) {
throw new IllegalArgumentException
("Value to parse may not be null");
}
if (parser == null)
parser = BasicHeaderValueParser.DEFAULT;
CharArrayBuffer buffer = new CharArrayBuffer(value.length());
buffer.append(value);
ParserCursor cursor = new ParserCursor(0, value.length());
return parser.parseNameValuePair(buffer, cursor);
}
// non-javadoc, see interface HeaderValueParser
public NameValuePair parseNameValuePair(final CharArrayBuffer buffer,
final ParserCursor cursor) {
return parseNameValuePair(buffer, cursor, ALL_DELIMITERS);
}
private static boolean isOneOf(final char ch, final char[] chs) {
if (chs != null) {
for (int i = 0; i < chs.length; i++) {
if (ch == chs[i]) {
return true;
}
}
}
return false;
}
public NameValuePair parseNameValuePair(final CharArrayBuffer buffer,
final ParserCursor cursor,
final char[] delimiters) {
if (buffer == null) {
throw new IllegalArgumentException("Char array buffer may not be null");
}
if (cursor == null) {
throw new IllegalArgumentException("Parser cursor may not be null");
}
boolean terminated = false;
int pos = cursor.getPos();
int indexFrom = cursor.getPos();
int indexTo = cursor.getUpperBound();
// Find name
String name = null;
while (pos < indexTo) {
char ch = buffer.charAt(pos);
if (ch == '=') {
break;
}
if (isOneOf(ch, delimiters)) {
terminated = true;
break;
}
pos++;
}
if (pos == indexTo) {
terminated = true;
name = buffer.substringTrimmed(indexFrom, indexTo);
} else {
name = buffer.substringTrimmed(indexFrom, pos);
pos++;
}
if (terminated) {
cursor.updatePos(pos);
return createNameValuePair(name, null);
}
// Find value
String value = null;
int i1 = pos;
boolean qouted = false;
boolean escaped = false;
while (pos < indexTo) {
char ch = buffer.charAt(pos);
if (ch == '"' && !escaped) {
qouted = !qouted;
}
if (!qouted && !escaped && isOneOf(ch, delimiters)) {
terminated = true;
break;
}
if (escaped) {
escaped = false;
} else {
escaped = qouted && ch == '\\';
}
pos++;
}
int i2 = pos;
// Trim leading white spaces
while (i1 < i2 && (HTTP.isWhitespace(buffer.charAt(i1)))) {
i1++;
}
// Trim trailing white spaces
while ((i2 > i1) && (HTTP.isWhitespace(buffer.charAt(i2 - 1)))) {
i2--;
}
// Strip away quotes if necessary
if (((i2 - i1) >= 2)
&& (buffer.charAt(i1) == '"')
&& (buffer.charAt(i2 - 1) == '"')) {
i1++;
i2--;
}
value = buffer.substring(i1, i2);
if (terminated) {
pos++;
}
cursor.updatePos(pos);
return createNameValuePair(name, value);
}
/**
* Creates a name-value pair.
* Called from {@link #parseNameValuePair}.
*
* @param name the name
* @param value the value, or <code>null</code>
*
* @return a name-value pair representing the arguments
*/
protected NameValuePair createNameValuePair(final String name, final String value) {
return new BasicNameValuePair(name, value);
}
}