org.jboss.resteasy.reactive.common.util.ParameterParser Maven / Gradle / Ivy
package org.jboss.resteasy.reactive.common.util;
import java.util.HashMap;
import java.util.Map;
/**
* A simple parser intended to parse sequences of name/value pairs.
* Parameter values are exptected to be enclosed in quotes if they
* contain unsafe characters, such as '=' characters or separators.
* Parameter values are optional and can be omitted.
*
* param1 = value; param2 = "anything goes; really"; param3
*
*
* @author Oleg Kalnichevski
*/
@SuppressWarnings("ForLoopReplaceableByForEach")
public class ParameterParser {
/**
* String to be parsed.
*/
private char[] chars = null;
/**
* Current position in the string.
*/
private int pos = 0;
/**
* Maximum position in the string.
*/
private int len = 0;
/**
* Start of a token.
*/
private int i1 = 0;
/**
* End of a token.
*/
private int i2 = 0;
/**
* Whether names stored in the map should be converted to lower case.
*/
private boolean lowerCaseNames = false;
/**
* Default ParameterParser constructor.
*/
public ParameterParser() {
super();
}
/**
* Are there any characters left to parse?
*
* @return true if there are unparsed characters,
* false otherwise.
*/
private boolean hasChar() {
return this.pos < this.len;
}
/**
* A helper method to process the parsed token. This method removes
* leading and trailing blanks as well as enclosing quotation marks,
* when necessary.
*
* @param quoted true if quotation marks are expected,
* false otherwise.
* @return the token
*/
private String getToken(boolean quoted) {
// Trim leading white spaces
while ((i1 < i2) && (Character.isWhitespace(chars[i1]))) {
i1++;
}
// Trim trailing white spaces
while ((i2 > i1) && (Character.isWhitespace(chars[i2 - 1]))) {
i2--;
}
// Strip away quotation marks if necessary
if (quoted) {
if (((i2 - i1) >= 2)
&& (chars[i1] == '"')
&& (chars[i2 - 1] == '"')) {
i1++;
i2--;
}
}
String result = null;
if (i2 > i1) {
result = new String(chars, i1, i2 - i1);
}
return result;
}
/**
* Tests if the given character is present in the array of characters.
*
* @param ch the character to test for presense in the array of characters
* @param charray the array of characters to test against
* @return true if the character is present in the array of
* characters, false otherwise.
*/
private boolean isOneOf(char ch, final char[] charray) {
boolean result = false;
for (int i = 0; i < charray.length; i++) {
if (ch == charray[i]) {
result = true;
break;
}
}
return result;
}
/**
* Parses out a token until any of the given terminators
* is encountered.
*
* @param terminators the array of terminating characters. Any of these
* characters when encountered signify the end of the token
* @return the token
*/
private String parseToken(final char[] terminators) {
char ch;
i1 = pos;
i2 = pos;
while (hasChar()) {
ch = chars[pos];
if (isOneOf(ch, terminators)) {
break;
}
i2++;
pos++;
}
return getToken(false);
}
/**
* Parses out a token until any of the given terminators
* is encountered outside the quotation marks.
*
* @param terminators the array of terminating characters. Any of these
* characters when encountered outside the quotation marks signify the end
* of the token
* @return the token
*/
private String parseQuotedToken(final char[] terminators) {
char ch;
i1 = pos;
i2 = pos;
boolean quoted = false;
boolean charEscaped = false;
while (hasChar()) {
ch = chars[pos];
if (!quoted && isOneOf(ch, terminators)) {
break;
}
if (!charEscaped && ch == '"') {
quoted = !quoted;
}
charEscaped = (!charEscaped && ch == '\\');
i2++;
pos++;
}
return getToken(true);
}
/**
* Returns true if parameter names are to be converted to lower
* case when name/value pairs are parsed.
*
* @return true if parameter names are to be
* converted to lower case when name/value pairs are parsed.
* Otherwise returns false
*/
public boolean isLowerCaseNames() {
return this.lowerCaseNames;
}
/**
* Sets the flag if parameter names are to be converted to lower case when
* name/value pairs are parsed.
*
* @param b true if parameter names are to be
* converted to lower case when name/value pairs are parsed.
* false otherwise.
*/
public void setLowerCaseNames(boolean b) {
this.lowerCaseNames = b;
}
/**
* Extracts a map of name/value pairs from the given string. Names are
* expected to be unique.
*
* @param str the string that contains a sequence of name/value pairs
* @param separator the name/value pairs separator
* @return a map of name/value pairs
*/
public Map parse(final String str, char separator) {
if (str == null) {
return emptyMap();
}
return parse(str.toCharArray(), separator);
}
/**
* Extracts a map of name/value pairs from the given array of
* characters. Names are expected to be unique.
*
* @param chars the array of characters that contains a sequence of
* name/value pairs
* @param separator the name/value pairs separator
* @return a map of name/value pairs
*/
public Map parse(final char[] chars, char separator) {
if (chars == null) {
return emptyMap();
}
return parse(chars, 0, chars.length, separator);
}
/**
* Extracts a map of name/value pairs from the given array of
* characters. Names are expected to be unique.
*
* @param chars the array of characters that contains a sequence of
* name/value pairs
* @param offset - the initial offset.
* @param length - the length.
* @param separator the name/value pairs separator
* @return a map of name/value pairs
*/
public Map parse(
final char[] chars,
int offset,
int length,
char separator) {
if (chars == null) {
return emptyMap();
}
Map params = newMap();
this.chars = chars;
this.pos = offset;
this.len = length;
String paramName = null;
String paramValue = null;
while (hasChar()) {
paramName = parseToken(new char[] { '=', separator });
paramValue = null;
if (hasChar() && (chars[pos] == '=')) {
pos++; // skip '='
paramValue = parseQuotedToken(new char[] {
separator });
}
if (hasChar() && (chars[pos] == separator)) {
pos++; // skip separator
}
if ((paramName != null) && (paramName.length() > 0)) {
if (this.lowerCaseNames) {
paramName = paramName.toLowerCase();
}
params.put(paramName, paramValue);
}
}
return params;
}
/**
* Takes string as-is and only changes the value of a specific attribute.
*
* @param chars the array of characters that contains a sequence of
* name/value pairs
* @param offset - the initial offset.
* @param length - the length.
* @param separator the name/value pairs separator
* @param name attribute name
* @param value new value
* @return updated parameters string
*/
public String setAttribute(
final char[] chars,
int offset,
int length,
char separator,
String name,
String value) {
this.chars = chars;
this.pos = offset;
this.len = length;
String paramName = null;
String paramValue = null;
int start = offset;
StringBuilder newChars = new StringBuilder();
while (hasChar()) {
paramName = parseToken(new char[] { '=', separator });
paramValue = null;
int index = -1;
if (paramName.equals(name)) {
newChars.append(new String(chars, start, pos - start));
}
if (hasChar() && (chars[pos] == '=')) {
pos++; // skip '='
paramValue = parseQuotedToken(new char[] {
separator });
}
if (paramName.equals(name)) {
newChars.append("=").append(value);
start = pos;
} else {
newChars.append(new String(chars, start, pos - start));
start = pos;
}
if (hasChar() && (chars[pos] == separator)) {
pos++; // skip separator
}
}
return newChars.toString();
}
protected Map emptyMap() {
return new HashMap<>();
}
protected Map newMap() {
return new HashMap<>();
}
}