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1: /* list.java -- 2: Copyright (C) 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.javax.swing.text.html.parser.models; 40: 41: import gnu.java.lang.CPStringBuilder; 42: 43: import java.io.Serializable; 44: 45: /** 46: * Part of the internal representation of the content model. 47: * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org) 48: */ 49: public class list 50: extends node 51: implements Serializable 52: { 53: private static final long serialVersionUID = 1; 54: 55: /** 56: * Setting to true means that the list nodes must always be connected 57: * by the same operation. This is far safer and clearer, but not 58: * required by default standard. 59: */ 60: public static boolean CLEAR; 61: 62: /** 63: * A list of nodes. 64: */ 65: public final node[] nodes; 66: 67: /** 68: * Creates a new model list that is a member of some enclosing list. 69: * @param binary_operator An operator with that this list is connected 70: * with other members of the enclosing list. 71: * @param unary_operator The unary operator for this list. 72: * @param a_nodes The nodes inside this list. 73: */ 74: public list(char binary_operator, char unary_operator, node[] a_nodes) 75: { 76: super(binary_operator, unary_operator, a_nodes); 77: nodes = a_nodes; 78: } 79: 80: /** 81: * Creates a new model list. Assigns the previous field. 82: * @param a_nodes The nodes for this list. 83: * @throws an error if the node elements are connected by the 84: * different operations. This is not supported, use grouping. 85: */ 86: public list(node[] a_nodes) 87: throws Error 88: { 89: this(',', (char) 0, a_nodes); 90: 91: int operation = nodes [ 0 ].binary; 92: 93: for (int i = 0; i < nodes.length; i++) 94: { 95: if (CLEAR && nodes [ i ].binary != operation) 96: throw new Error("List members can only be connected by " + 97: "the same operation, use grouping" 98: ); 99: 100: if (i > 0) 101: nodes [ i ].previous = nodes [ i - 1 ]; 102: } 103: } 104: 105: /** 106: * Returns true if all members in the list are closed. 107: */ 108: public boolean isClosed() 109: { 110: if (super.isClosed()) 111: return true; 112: for (int i = 0; i < nodes.length; i++) 113: { 114: if (!nodes [ i ].isClosed()) 115: return false; 116: } 117: return true; 118: } 119: 120: /** 121: * Find the token that could match as the next token in 122: * the token list. 123: * 124: * @return Such token object or null if none is found. 125: */ 126: public Object findFreeNode() 127: { 128: Object fn; 129: for (int j = 0; j < nodes.length; j++) 130: { 131: if (!nodes [ j ].isClosed()) 132: { 133: fn = nodes [ j ].findFreeNode(); 134: if (fn != null) 135: return fn; 136: } 137: } 138: return null; 139: } 140: 141: /** 142: * Tries to match this list agains the given token sequence. 143: * @param tokens the sequence of the tokens to match. 144: * @return true if the valid match is found. 145: */ 146: public boolean matches(Object[] tokens) 147: { 148: reset(); 149: 150: Object x; 151: boolean m; 152: boolean matched = false; 153: 154: for (int i = 0; i < tokens.length; i++) 155: { 156: matched = false; 157: x = tokens [ i ]; 158: 159: nodescan: 160: for (int j = 0; j < nodes.length; j++) 161: { 162: if (!nodes [ j ].isClosed()) 163: { 164: m = nodes [ j ].performMatch(x); 165: 166: if (m) 167: { 168: matched = true; 169: break nodescan; 170: } 171: } 172: } 173: if (!matched) 174: return false; 175: } 176: 177: boolean valid = true; 178: 179: for (int i = 0; i < nodes.length; i++) 180: { 181: if (!nodes [ i ].valid()) 182: valid = false; 183: } 184: 185: return valid; 186: } 187: 188: /** 189: * The list never closes, despite it is trated as closed 190: * if all members in the list are closed. 191: * @return false. 192: */ 193: public boolean mustClose() 194: { 195: return false; 196: } 197: 198: /** 199: * Perform a match operation for the single token 200: * against this list. 201: * @param token a token to match. 202: * @return true if the match is found. 203: */ 204: public boolean performMatch(Object token) 205: { 206: boolean ok = false; 207: Matching: 208: for (int i = 0; i < nodes.length; i++) 209: { 210: ok = nodes [ i ].performMatch(token); 211: 212: if (ok) 213: break Matching; 214: } 215: 216: if (ok) 217: matches(); 218: 219: return ok; 220: } 221: 222: /** 223: * Prepeares the list for the next matching operation. 224: */ 225: public void reset() 226: { 227: super.reset(); 228: for (int i = 0; i < nodes.length; i++) 229: nodes [ i ].reset(); 230: } 231: 232: /** 233: * Check if the provided token can match as a next token in the 234: * list. In the case of match, the list state changes, moving 235: * current position after the matched token. However if this method 236: * returns a suggested new token to insert before the provided one, 237: * the state of the list does not change. 238: * @return Boolean.TRUE if the match is found, 239: * Boolean.FALSE if the match is not possible and no token can be 240: * inserted to make the match valid. Otherwise, returns the 241: * token object that can be inserted before the last token in the 242: * list, probably (not for sure) making the match valid. 243: * If the object is an instance of Element or TagElement, 244: * it is first ensured that the object flag "omit start" is set. 245: */ 246: public Object show(Object x) 247: { 248: boolean m; 249: boolean matched = false; 250: 251: nodescan: 252: for (int j = 0; j < nodes.length; j++) 253: { 254: if (!nodes [ j ].isClosed()) 255: { 256: m = nodes [ j ].performMatch(x); 257: 258: if (m) 259: { 260: matched = true; 261: break nodescan; 262: } 263: else 264: { 265: // For comma operation, only first not closed 266: // node must be tested for a match. 267: // unless it allows matching zero times. 268: if (binary == ',' && 269: !(nodes [ j ].unary == '?' || nodes [ j ].unary == '*') 270: ) 271: break nodescan; 272: } 273: } 274: } 275: 276: if (!matched) 277: { 278: // Find and return that would be matched. 279: Object freeNode = findFreeNode(); 280: if (freeNode == null) 281: return Boolean.FALSE; 282: else 283: return freeNode; 284: } 285: 286: for (int i = 0; i < nodes.length; i++) 287: if (!nodes [ i ].validPreliminary()) 288: { 289: return Boolean.FALSE; 290: } 291: 292: return Boolean.TRUE; 293: } 294: 295: /** 296: * Returns a string representation of the list. 297: * @return String representation, similar to BNF expression. 298: */ 299: public String toString() 300: { 301: CPStringBuilder b = new CPStringBuilder(); 302: b.append(" ( "); 303: for (int i = 0; i < nodes.length; i++) 304: { 305: if (i > 0) 306: b.append(" " + (char) nodes [ i ].binary + " "); 307: b.append(nodes [ i ]); 308: } 309: 310: b.append(" )"); 311: if (unary != 0) 312: b.append((char) unary); 313: else 314: b.append(' '); 315: return b.toString(); 316: } 317: 318: /** 319: * Returns true if all memebers in the list are valid. 320: */ 321: public boolean valid() 322: { 323: for (int i = 0; i < nodes.length; i++) 324: { 325: if (!nodes [ i ].valid()) 326: return false; 327: } 328: return true; 329: } 330: 331: /** 332: * Returns true if all memebers in the list are either valid 333: * or unvisited. The unvisited members can become valid after 334: * more tokens will be shown. 335: */ 336: public boolean validPreliminary() 337: { 338: if (silenceAllowed()) 339: { 340: boolean everVisited = false; 341: for (int i = 0; i < nodes.length; i++) 342: { 343: if (nodes [ i ].visits > 0) 344: { 345: everVisited = true; 346: break; 347: } 348: } 349: if (!everVisited) 350: return true; 351: } 352: 353: for (int i = 0; i < nodes.length; i++) 354: { 355: if (!nodes [ i ].validPreliminary()) 356: return false; 357: } 358: return true; 359: } 360: 361: /** 362: * Closes all members in the list. 363: */ 364: protected void close() 365: { 366: super.close(); 367: for (int i = 0; i < nodes.length; i++) 368: { 369: nodes [ i ].close(); 370: } 371: } 372: 373: /** 374: * Compare given token with the token of this node. 375: * If the token represents a <code>list</code>, the call may be 376: * delegeted to the child subnodes. 377: * @param a_token A token to compare. 378: * @return True if the token matches the token of this node. 379: */ 380: protected boolean compare(Object a_token) 381: { 382: return performMatch(a_token); 383: } 384: }