ohair | 6c32066 | 2012-03-04 11:55:34 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * reserved comment block |
| 3 | * DO NOT REMOVE OR ALTER! |
| 4 | */ |
| 5 | /* |
| 6 | * Copyright 1999-2004 The Apache Software Foundation. |
| 7 | * |
| 8 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 9 | * you may not use this file except in compliance with the License. |
| 10 | * You may obtain a copy of the License at |
| 11 | * |
| 12 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 13 | * |
| 14 | * Unless required by applicable law or agreed to in writing, software |
| 15 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 16 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 17 | * See the License for the specific language governing permissions and |
| 18 | * limitations under the License. |
| 19 | */ |
| 20 | /* |
| 21 | * $Id: FilterExprWalker.java,v 1.2.4.2 2005/09/14 19:45:23 jeffsuttor Exp $ |
| 22 | */ |
| 23 | package com.sun.org.apache.xpath.internal.axes; |
| 24 | |
| 25 | import com.sun.org.apache.xml.internal.dtm.Axis; |
| 26 | import com.sun.org.apache.xml.internal.dtm.DTM; |
| 27 | import com.sun.org.apache.xml.internal.dtm.DTMIterator; |
| 28 | import com.sun.org.apache.xpath.internal.Expression; |
| 29 | import com.sun.org.apache.xpath.internal.ExpressionOwner; |
| 30 | import com.sun.org.apache.xpath.internal.XPathContext; |
| 31 | import com.sun.org.apache.xpath.internal.XPathVisitor; |
| 32 | import com.sun.org.apache.xpath.internal.compiler.Compiler; |
| 33 | import com.sun.org.apache.xpath.internal.compiler.OpCodes; |
| 34 | import com.sun.org.apache.xpath.internal.objects.XNodeSet; |
| 35 | |
| 36 | /** |
| 37 | * Walker for the OP_VARIABLE, or OP_EXTFUNCTION, or OP_FUNCTION, or OP_GROUP, |
| 38 | * op codes. |
| 39 | * @see <a href="http://www.w3.org/TR/xpath#NT-FilterExpr">XPath FilterExpr descriptions</a> |
| 40 | */ |
| 41 | public class FilterExprWalker extends AxesWalker |
| 42 | { |
| 43 | static final long serialVersionUID = 5457182471424488375L; |
| 44 | |
| 45 | /** |
| 46 | * Construct a FilterExprWalker using a LocPathIterator. |
| 47 | * |
| 48 | * @param locPathIterator non-null reference to the parent iterator. |
| 49 | */ |
| 50 | public FilterExprWalker(WalkingIterator locPathIterator) |
| 51 | { |
| 52 | super(locPathIterator, Axis.FILTEREDLIST); |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Init a FilterExprWalker. |
| 57 | * |
| 58 | * @param compiler non-null reference to the Compiler that is constructing. |
| 59 | * @param opPos positive opcode position for this step. |
| 60 | * @param stepType The type of step. |
| 61 | * |
| 62 | * @throws javax.xml.transform.TransformerException |
| 63 | */ |
| 64 | public void init(Compiler compiler, int opPos, int stepType) |
| 65 | throws javax.xml.transform.TransformerException |
| 66 | { |
| 67 | |
| 68 | super.init(compiler, opPos, stepType); |
| 69 | |
| 70 | // Smooth over an anomily in the opcode map... |
| 71 | switch (stepType) |
| 72 | { |
| 73 | case OpCodes.OP_FUNCTION : |
| 74 | case OpCodes.OP_EXTFUNCTION : |
| 75 | m_mustHardReset = true; |
| 76 | case OpCodes.OP_GROUP : |
| 77 | case OpCodes.OP_VARIABLE : |
| 78 | m_expr = compiler.compile(opPos); |
| 79 | m_expr.exprSetParent(this); |
| 80 | //if((OpCodes.OP_FUNCTION == stepType) && (m_expr instanceof com.sun.org.apache.xalan.internal.templates.FuncKey)) |
| 81 | if(m_expr instanceof com.sun.org.apache.xpath.internal.operations.Variable) |
| 82 | { |
| 83 | // hack/temp workaround |
| 84 | m_canDetachNodeset = false; |
| 85 | } |
| 86 | break; |
| 87 | default : |
| 88 | m_expr = compiler.compile(opPos + 2); |
| 89 | m_expr.exprSetParent(this); |
| 90 | } |
| 91 | // if(m_expr instanceof WalkingIterator) |
| 92 | // { |
| 93 | // WalkingIterator wi = (WalkingIterator)m_expr; |
| 94 | // if(wi.getFirstWalker() instanceof FilterExprWalker) |
| 95 | // { |
| 96 | // FilterExprWalker fw = (FilterExprWalker)wi.getFirstWalker(); |
| 97 | // if(null == fw.getNextWalker()) |
| 98 | // { |
| 99 | // m_expr = fw.m_expr; |
| 100 | // m_expr.exprSetParent(this); |
| 101 | // } |
| 102 | // } |
| 103 | // |
| 104 | // } |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Detaches the walker from the set which it iterated over, releasing |
| 109 | * any computational resources and placing the iterator in the INVALID |
| 110 | * state. |
| 111 | */ |
| 112 | public void detach() |
| 113 | { |
| 114 | super.detach(); |
| 115 | if (m_canDetachNodeset) |
| 116 | { |
| 117 | m_exprObj.detach(); |
| 118 | } |
| 119 | m_exprObj = null; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * Set the root node of the TreeWalker. |
| 124 | * |
| 125 | * @param root non-null reference to the root, or starting point of |
| 126 | * the query. |
| 127 | */ |
| 128 | public void setRoot(int root) |
| 129 | { |
| 130 | |
| 131 | super.setRoot(root); |
| 132 | |
| 133 | m_exprObj = FilterExprIteratorSimple.executeFilterExpr(root, |
| 134 | m_lpi.getXPathContext(), m_lpi.getPrefixResolver(), |
| 135 | m_lpi.getIsTopLevel(), m_lpi.m_stackFrame, m_expr); |
| 136 | |
| 137 | } |
| 138 | |
| 139 | /** |
| 140 | * Get a cloned FilterExprWalker. |
| 141 | * |
| 142 | * @return A new FilterExprWalker that can be used without mutating this one. |
| 143 | * |
| 144 | * @throws CloneNotSupportedException |
| 145 | */ |
| 146 | public Object clone() throws CloneNotSupportedException |
| 147 | { |
| 148 | |
| 149 | FilterExprWalker clone = (FilterExprWalker) super.clone(); |
| 150 | |
| 151 | // clone.m_expr = (Expression)((Expression)m_expr).clone(); |
| 152 | if (null != m_exprObj) |
| 153 | clone.m_exprObj = (XNodeSet) m_exprObj.clone(); |
| 154 | |
| 155 | return clone; |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * This method needs to override AxesWalker.acceptNode because FilterExprWalkers |
| 160 | * don't need to, and shouldn't, do a node test. |
| 161 | * @param n The node to check to see if it passes the filter or not. |
| 162 | * @return a constant to determine whether the node is accepted, |
| 163 | * rejected, or skipped, as defined above . |
| 164 | */ |
| 165 | public short acceptNode(int n) |
| 166 | { |
| 167 | |
| 168 | try |
| 169 | { |
| 170 | if (getPredicateCount() > 0) |
| 171 | { |
| 172 | countProximityPosition(0); |
| 173 | |
| 174 | if (!executePredicates(n, m_lpi.getXPathContext())) |
| 175 | return DTMIterator.FILTER_SKIP; |
| 176 | } |
| 177 | |
| 178 | return DTMIterator.FILTER_ACCEPT; |
| 179 | } |
| 180 | catch (javax.xml.transform.TransformerException se) |
| 181 | { |
| 182 | throw new RuntimeException(se.getMessage()); |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Moves the <code>TreeWalker</code> to the next visible node in document |
| 188 | * order relative to the current node, and returns the new node. If the |
| 189 | * current node has no next node, or if the search for nextNode attempts |
| 190 | * to step upward from the TreeWalker's root node, returns |
| 191 | * <code>null</code> , and retains the current node. |
| 192 | * @return The new node, or <code>null</code> if the current node has no |
| 193 | * next node in the TreeWalker's logical view. |
| 194 | */ |
| 195 | public int getNextNode() |
| 196 | { |
| 197 | |
| 198 | if (null != m_exprObj) |
| 199 | { |
| 200 | int next = m_exprObj.nextNode(); |
| 201 | return next; |
| 202 | } |
| 203 | else |
| 204 | return DTM.NULL; |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Get the index of the last node that can be itterated to. |
| 209 | * |
| 210 | * |
| 211 | * @param xctxt XPath runtime context. |
| 212 | * |
| 213 | * @return the index of the last node that can be itterated to. |
| 214 | */ |
| 215 | public int getLastPos(XPathContext xctxt) |
| 216 | { |
| 217 | return m_exprObj.getLength(); |
| 218 | } |
| 219 | |
| 220 | /** The contained expression. Should be non-null. |
| 221 | * @serial */ |
| 222 | private Expression m_expr; |
| 223 | |
| 224 | /** The result of executing m_expr. Needs to be deep cloned on clone op. */ |
| 225 | transient private XNodeSet m_exprObj; |
| 226 | |
| 227 | private boolean m_mustHardReset = false; |
| 228 | private boolean m_canDetachNodeset = true; |
| 229 | |
| 230 | /** |
| 231 | * This function is used to fixup variables from QNames to stack frame |
| 232 | * indexes at stylesheet build time. |
| 233 | * @param vars List of QNames that correspond to variables. This list |
| 234 | * should be searched backwards for the first qualified name that |
| 235 | * corresponds to the variable reference qname. The position of the |
| 236 | * QName in the vector from the start of the vector will be its position |
| 237 | * in the stack frame (but variables above the globalsTop value will need |
| 238 | * to be offset to the current stack frame). |
| 239 | */ |
| 240 | public void fixupVariables(java.util.Vector vars, int globalsSize) |
| 241 | { |
| 242 | super.fixupVariables(vars, globalsSize); |
| 243 | m_expr.fixupVariables(vars, globalsSize); |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * Get the inner contained expression of this filter. |
| 248 | */ |
| 249 | public Expression getInnerExpression() |
| 250 | { |
| 251 | return m_expr; |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * Set the inner contained expression of this filter. |
| 256 | */ |
| 257 | public void setInnerExpression(Expression expr) |
| 258 | { |
| 259 | expr.exprSetParent(this); |
| 260 | m_expr = expr; |
| 261 | } |
| 262 | |
| 263 | |
| 264 | /** |
| 265 | * Get the analysis bits for this walker, as defined in the WalkerFactory. |
| 266 | * @return One of WalkerFactory#BIT_DESCENDANT, etc. |
| 267 | */ |
| 268 | public int getAnalysisBits() |
| 269 | { |
| 270 | if (null != m_expr && m_expr instanceof PathComponent) |
| 271 | { |
| 272 | return ((PathComponent) m_expr).getAnalysisBits(); |
| 273 | } |
| 274 | return WalkerFactory.BIT_FILTER; |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Returns true if all the nodes in the iteration well be returned in document |
| 279 | * order. |
| 280 | * Warning: This can only be called after setRoot has been called! |
| 281 | * |
| 282 | * @return true as a default. |
| 283 | */ |
| 284 | public boolean isDocOrdered() |
| 285 | { |
| 286 | return m_exprObj.isDocOrdered(); |
| 287 | } |
| 288 | |
| 289 | /** |
| 290 | * Returns the axis being iterated, if it is known. |
| 291 | * |
| 292 | * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple |
| 293 | * types. |
| 294 | */ |
| 295 | public int getAxis() |
| 296 | { |
| 297 | return m_exprObj.getAxis(); |
| 298 | } |
| 299 | |
| 300 | class filterExprOwner implements ExpressionOwner |
| 301 | { |
| 302 | /** |
| 303 | * @see ExpressionOwner#getExpression() |
| 304 | */ |
| 305 | public Expression getExpression() |
| 306 | { |
| 307 | return m_expr; |
| 308 | } |
| 309 | |
| 310 | /** |
| 311 | * @see ExpressionOwner#setExpression(Expression) |
| 312 | */ |
| 313 | public void setExpression(Expression exp) |
| 314 | { |
| 315 | exp.exprSetParent(FilterExprWalker.this); |
| 316 | m_expr = exp; |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | /** |
| 321 | * This will traverse the heararchy, calling the visitor for |
| 322 | * each member. If the called visitor method returns |
| 323 | * false, the subtree should not be called. |
| 324 | * |
| 325 | * @param visitor The visitor whose appropriate method will be called. |
| 326 | */ |
| 327 | public void callPredicateVisitors(XPathVisitor visitor) |
| 328 | { |
| 329 | m_expr.callVisitors(new filterExprOwner(), visitor); |
| 330 | |
| 331 | super.callPredicateVisitors(visitor); |
| 332 | } |
| 333 | |
| 334 | |
| 335 | /** |
| 336 | * @see Expression#deepEquals(Expression) |
| 337 | */ |
| 338 | public boolean deepEquals(Expression expr) |
| 339 | { |
| 340 | if (!super.deepEquals(expr)) |
| 341 | return false; |
| 342 | |
| 343 | FilterExprWalker walker = (FilterExprWalker)expr; |
| 344 | if(!m_expr.deepEquals(walker.m_expr)) |
| 345 | return false; |
| 346 | |
| 347 | return true; |
| 348 | } |
| 349 | |
| 350 | |
| 351 | |
| 352 | } |