1 // $Id: CQLNode.java,v 1.16 2002-12-04 16:56:06 mike Exp $
3 package org.z3950.zing.cql;
4 import java.util.Properties;
5 import java.util.Vector;
9 * Represents a node in a CQL parse-tree.
11 * @version $Id: CQLNode.java,v 1.16 2002-12-04 16:56:06 mike Exp $
13 public abstract class CQLNode {
14 CQLNode() {} // prevent javadoc from documenting this
17 * Translates a parse-tree into an XCQL document.
20 * The number of levels to indent the top element of the XCQL
21 * document. This will typically be 0 when invoked by an
22 * application; it takes higher values when this method is
23 * invoked recursively for nodes further down the tree.
25 * A String containing an XCQL document equivalent to the
26 * parse-tree whose root is this node.
28 public String toXCQL(int level) {
29 return toXCQL(level, new Vector());
32 abstract public String toXCQL(int level, Vector prefixes);
34 protected static String renderPrefixes(int level, Vector prefixes) {
35 if (prefixes.size() == 0)
37 String res = indent(level) + "<prefixes>\n";
38 for (int i = 0; i < prefixes.size(); i++) {
39 CQLPrefix p = (CQLPrefix) prefixes.get(i);
40 res += indent(level+1) + "<prefix>\n";
42 res += indent(level+2) + "<name>" + p.name + "</name>\n";
43 res += indent(level+2) +
44 "<identifier>" + p.identifier + "</identifier>\n";
45 res += indent(level+1) + "</prefix>\n";
47 return res + indent(level) + "</prefixes>\n";
51 * Decompiles a parse-tree into a CQL query.
54 * A String containing a CQL query equivalent to the parse-tree
55 * whose root is this node, so that compiling that query will
56 * yield an identical tree.
58 abstract public String toCQL();
61 * Renders a parse-tree into a Yaz-style PQF string.
62 * PQF, or Prefix Query Format, is a cryptic but powerful notation
63 * that can be trivially mapped, one-to-one, int Z39.50 Type-1 and
64 * Type-101 queries. A specification for the format can be found
66 * <A href="http://indexdata.dk/yaz/doc/tools.php#PQF"
67 * >Chapter 7 (Supporting Tools)</A> of the
68 * <A href="http://indexdata.dk/yaz/">YAZ</A> manual.
71 * A <TT>Properties</TT> object containing configuration
72 * information that specifies the mapping from CQL qualifiers,
73 * relations, etc. to Type-1 attributes. The mapping
74 * specification is described in the cql-java distribution's
75 * sample PQF-mapping configuration file,
76 * <TT>etc/pqf.properties</TT>, which see.
78 * A String containing a PQF query equivalent to the parse-tree
79 * whose root is this node. This may be fed into the tool of
80 * your choice to obtain a BER-encoded packet.
82 abstract public String toPQF(Properties config)
83 throws PQFTranslationException;
86 * Returns a String of spaces for indenting to the specified level.
88 protected static String indent(int level) { return Utils.indent(level); }
91 * Returns the argument String quoted for XML.
92 * For example, each occurrence of <TT><</TT> is translated to
95 protected static String xq(String str) { return Utils.xq(str); }
100 abstract public byte[] toType1(Properties config)
101 throws PQFTranslationException;
104 protected static final int UNIVERSAL = 0;
105 protected static final int APPLICATION = 1;
106 protected static final int CONTEXT = 2;
107 protected static final int PRIVATE = 3;
110 protected static final int PRIMITIVE = 0;
111 protected static final int CONSTRUCTED = 1;
113 // ASN.1 UNIVERSAL data types
114 public static final byte BOOLEAN = 1;
115 public static final byte INTEGER = 2;
116 public static final byte BITSTRING = 3;
117 public static final byte OCTETSTRING = 4;
118 public static final byte NULL = 5;
119 public static final byte OBJECTIDENTIFIER = 6;
120 public static final byte OBJECTDESCRIPTOR = 7;
121 public static final byte EXTERNAL = 8;
122 public static final byte ENUMERATED = 10;
123 public static final byte SEQUENCE = 16;
124 public static final byte SET = 17;
125 public static final byte VISIBLESTRING = 26;
126 public static final byte GENERALSTRING = 27;
128 protected static final int putTag(int asn1class, int fldid, int form,
129 byte[] record, int offset) {
131 record[offset++] = (byte)(fldid + asn1class*64 + form*32);
133 record[offset++] = (byte)(31 + asn1class*64 + form*32);
135 record[offset++] = (byte)(fldid);
137 record[offset++] = (byte)(128 + fldid/128);
138 record[offset++] = (byte)(fldid % 128);
145 * Put a length directly into a BER record.
147 * @param length length to put into record
148 * @return the new, incremented value of the offset parameter.
150 public // ### shouldn't this be protected?
151 static final int putLen(int len, byte[] record, int offset) {
154 record[offset++] = (byte)len;
157 record[offset] = (byte)(lenLen(len) - 1);
158 for (t = record[offset]; t > 0; t--) {
159 record[offset+t] = (byte)(len & 0xff);
163 offset += (record[offset]&0xff) + 1;
164 record[t] += 128; // turn on bit 8 in length byte.
170 * Get the length needed to represent the given length.
172 * @param length determine length needed to encode this
173 * @return length needed to encode given length
175 protected // ### shouldn't this be private?
176 static final int lenLen(int length) {
178 return ((length < 128) ? 1 :
180 (length < 65536L) ? 3 : 4);
184 * Get the length needed to represent the given number.
186 * @param number determine length needed to encode this
187 * @return length needed to encode given number
189 protected static final int numLen(long num) {
190 num = num < 0 ? -num : num;
191 // ### Wouldn't this be better done algorithmically?
192 // Or at least with the constants expressed in hex?
193 return ((num < 128) ? 1 :
195 (num < 8388608) ? 3 :
196 (num < 2147483648L) ? 4 :
197 (num < 549755813888L) ? 5 :
198 (num < 140737488355328L) ? 6 :
199 (num < 36028797018963968L) ? 7 : 8);
203 * Put a number into a given buffer
205 * @param num number to put into buffer
206 * @param record buffer to use
207 * @param offset offset into buffer
208 * @return the new, incremented value of the offset parameter.
210 protected static final int putNum(long num, byte record[], int offset) {
213 for (int count = cnt - 1; count >= 0; count--) {
214 record[offset+count] = (byte)(num & 0xff);
220 // Used only by the makeOID() method
221 private static final java.util.Hashtable madeOIDs =
222 new java.util.Hashtable(10);
224 protected static final byte[] makeOID(String oid) {
226 int dot, offset = 0, oidOffset = 0, value;
228 if ((o = (byte[])madeOIDs.get(oid)) == null) {
231 // Isn't this kind of thing excruciating in Java?
232 while (oidOffset < oid.length() &&
233 Character.isDigit(oid.charAt(oidOffset)) == true) {
234 if (offset > 90) // too large
237 dot = oid.indexOf('.', oidOffset);
241 value = Integer.parseInt(oid.substring(oidOffset, dot));
243 if (offset == 0) { // 1st two are special
244 if (dot == -1) // ### can't happen: -1 is reassigned above
245 return null; // can't be this short
246 oidOffset = dot+1; // skip past '.'
248 dot = oid.indexOf('.', oidOffset);
254 Integer.parseInt(oid.substring(oidOffset,dot));
258 o[offset++] = (byte)value;
261 byte bits[] = new byte[12]; // save a 84 (12*7) bit number
264 bits[count++] = (byte)(value & 0x7f);
268 // Now place in the correct order
270 o[offset++] = (byte)(bits[count] | 0x80);
272 o[offset++] = bits[count];
275 dot = oid.indexOf('.', oidOffset);
282 byte[] ptr = new byte[offset];
283 System.arraycopy(o, 0, ptr, 0, offset);
284 madeOIDs.put(oid, ptr);
290 public static final byte[] makeQuery(CQLNode root, Properties properties)
291 throws PQFTranslationException {
292 byte[] rpnStructure = root.toType1(properties);
293 byte[] qry = new byte[rpnStructure.length+100];
295 offset = putTag(CONTEXT, 1, CONSTRUCTED, qry, offset);
296 qry[offset++] = (byte)(0x80&0xff); // indefinite length
297 offset = putTag(UNIVERSAL, OBJECTIDENTIFIER, PRIMITIVE, qry, offset);
298 byte[] oid = makeOID("1.2.840.10003.3.1"); // bib-1
299 offset = putLen(oid.length, qry, offset);
300 System.arraycopy(oid, 0, qry, offset, oid.length);
301 offset += oid.length;
302 System.arraycopy(rpnStructure, 0, qry, offset, rpnStructure.length);
303 offset += rpnStructure.length;
304 qry[offset++] = 0x00; // end of query
305 qry[offset++] = 0x00;
306 byte[] q = new byte[offset];
307 System.arraycopy(qry, 0, q, 0, offset);