Java example source code file (HeaderParser.java)
The HeaderParser.java Java example source code
/*
* Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.net.www;
import java.util.Iterator;
/* This is useful for the nightmare of parsing multi-part HTTP/RFC822 headers
* sensibly:
* From a String like: 'timeout=15, max=5'
* create an array of Strings:
* { {"timeout", "15"},
* {"max", "5"}
* }
* From one like: 'Basic Realm="FuzzFace" Foo="Biz Bar Baz"'
* create one like (no quotes in literal):
* { {"basic", null},
* {"realm", "FuzzFace"}
* {"foo", "Biz Bar Baz"}
* }
* keys are converted to lower case, vals are left as is....
*
* @author Dave Brown
*/
public class HeaderParser {
/* table of key/val pairs */
String raw;
String[][] tab;
int nkeys;
int asize = 10; // initial size of array is 10
public HeaderParser(String raw) {
this.raw = raw;
tab = new String[asize][2];
parse();
}
private HeaderParser () {
}
/**
* create a new HeaderParser from this, whose keys (and corresponding values)
* range from "start" to "end-1"
*/
public HeaderParser subsequence (int start, int end) {
if (start == 0 && end == nkeys) {
return this;
}
if (start < 0 || start >= end || end > nkeys)
throw new IllegalArgumentException ("invalid start or end");
HeaderParser n = new HeaderParser ();
n.tab = new String [asize][2];
n.asize = asize;
System.arraycopy (tab, start, n.tab, 0, (end-start));
n.nkeys= (end-start);
return n;
}
private void parse() {
if (raw != null) {
raw = raw.trim();
char[] ca = raw.toCharArray();
int beg = 0, end = 0, i = 0;
boolean inKey = true;
boolean inQuote = false;
int len = ca.length;
while (end < len) {
char c = ca[end];
if ((c == '=') && !inQuote) { // end of a key
tab[i][0] = new String(ca, beg, end-beg).toLowerCase();
inKey = false;
end++;
beg = end;
} else if (c == '\"') {
if (inQuote) {
tab[i++][1]= new String(ca, beg, end-beg);
inQuote=false;
do {
end++;
} while (end < len && (ca[end] == ' ' || ca[end] == ','));
inKey=true;
beg=end;
} else {
inQuote=true;
end++;
beg=end;
}
} else if (c == ' ' || c == ',') { // end key/val, of whatever we're in
if (inQuote) {
end++;
continue;
} else if (inKey) {
tab[i++][0] = (new String(ca, beg, end-beg)).toLowerCase();
} else {
tab[i++][1] = (new String(ca, beg, end-beg));
}
while (end < len && (ca[end] == ' ' || ca[end] == ',')) {
end++;
}
inKey = true;
beg = end;
} else {
end++;
}
if (i == asize) {
asize = asize * 2;
String[][] ntab = new String[asize][2];
System.arraycopy (tab, 0, ntab, 0, tab.length);
tab = ntab;
}
}
// get last key/val, if any
if (--end > beg) {
if (!inKey) {
if (ca[end] == '\"') {
tab[i++][1] = (new String(ca, beg, end-beg));
} else {
tab[i++][1] = (new String(ca, beg, end-beg+1));
}
} else {
tab[i++][0] = (new String(ca, beg, end-beg+1)).toLowerCase();
}
} else if (end == beg) {
if (!inKey) {
if (ca[end] == '\"') {
tab[i++][1] = String.valueOf(ca[end-1]);
} else {
tab[i++][1] = String.valueOf(ca[end]);
}
} else {
tab[i++][0] = String.valueOf(ca[end]).toLowerCase();
}
}
nkeys=i;
}
}
public String findKey(int i) {
if (i < 0 || i > asize)
return null;
return tab[i][0];
}
public String findValue(int i) {
if (i < 0 || i > asize)
return null;
return tab[i][1];
}
public String findValue(String key) {
return findValue(key, null);
}
public String findValue(String k, String Default) {
if (k == null)
return Default;
k = k.toLowerCase();
for (int i = 0; i < asize; ++i) {
if (tab[i][0] == null) {
return Default;
} else if (k.equals(tab[i][0])) {
return tab[i][1];
}
}
return Default;
}
class ParserIterator implements Iterator<String> {
int index;
boolean returnsValue; // or key
ParserIterator (boolean returnValue) {
returnsValue = returnValue;
}
public boolean hasNext () {
return index<nkeys;
}
public String next () {
return tab[index++][returnsValue?1:0];
}
public void remove () {
throw new UnsupportedOperationException ("remove not supported");
}
}
public Iterator<String> keys () {
return new ParserIterator (false);
}
public Iterator<String> values () {
return new ParserIterator (true);
}
public String toString () {
Iterator<String> k = keys();
StringBuffer sbuf = new StringBuffer();
sbuf.append ("{size="+asize+" nkeys="+nkeys+" ");
for (int i=0; k.hasNext(); i++) {
String key = k.next();
String val = findValue (i);
if (val != null && "".equals (val)) {
val = null;
}
sbuf.append (" {"+key+(val==null?"":","+val)+"}");
if (k.hasNext()) {
sbuf.append (",");
}
}
sbuf.append (" }");
return new String (sbuf);
}
public int findInt(String k, int Default) {
try {
return Integer.parseInt(findValue(k, String.valueOf(Default)));
} catch (Throwable t) {
return Default;
}
}
/*
public static void main(String[] a) throws Exception {
System.out.print("enter line to parse> ");
System.out.flush();
DataInputStream dis = new DataInputStream(System.in);
String line = dis.readLine();
HeaderParser p = new HeaderParser(line);
for (int i = 0; i < asize; ++i) {
if (p.findKey(i) == null) break;
String v = p.findValue(i);
System.out.println(i + ") " +p.findKey(i) + "="+v);
}
System.out.println("Done!");
}
*/
}
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