| /* EqualityExpr.java -- | |
| Copyright (C) 2004 Free Software Foundation, Inc. | |
| This file is part of GNU Classpath. | |
| GNU Classpath is free software; you can redistribute it and/or modify | |
| it under the terms of the GNU General Public License as published by | |
| the Free Software Foundation; either version 2, or (at your option) | |
| any later version. | |
| GNU Classpath 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 for more details. | |
| You should have received a copy of the GNU General Public License | |
| along with GNU Classpath; see the file COPYING. If not, write to the | |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
| 02110-1301 USA. | |
| Linking this library statically or dynamically with other modules is | |
| making a combined work based on this library. Thus, the terms and | |
| conditions of the GNU General Public License cover the whole | |
| combination. | |
| As a special exception, the copyright holders of this library give you | |
| permission to link this library with independent modules to produce an | |
| executable, regardless of the license terms of these independent | |
| modules, and to copy and distribute the resulting executable under | |
| terms of your choice, provided that you also meet, for each linked | |
| independent module, the terms and conditions of the license of that | |
| module. An independent module is a module which is not derived from | |
| or based on this library. If you modify this library, you may extend | |
| this exception to your version of the library, but you are not | |
| obligated to do so. If you do not wish to do so, delete this | |
| exception statement from your version. */ | |
| package gnu.xml.xpath; | |
| import java.util.Collection; | |
| import java.util.Iterator; | |
| import javax.xml.namespace.QName; | |
| import org.w3c.dom.Node; | |
| /** | |
| * Boolean equality expression. | |
| * | |
| * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> | |
| */ | |
| final class EqualityExpr | |
| extends Expr | |
| { | |
| final Expr lhs; | |
| final Expr rhs; | |
| final boolean invert; | |
| EqualityExpr(Expr lhs, Expr rhs, boolean invert) | |
| { | |
| this.lhs = lhs; | |
| this.rhs = rhs; | |
| this.invert = invert; | |
| } | |
| public Object evaluate(Node context, int pos, int len) | |
| { | |
| boolean val = evaluateImpl(context, pos, len); | |
| if (invert) | |
| { | |
| return val ? Boolean.FALSE : Boolean.TRUE; | |
| } | |
| else | |
| { | |
| return val ? Boolean.TRUE : Boolean.FALSE; | |
| } | |
| } | |
| private boolean evaluateImpl(Node context, int pos, int len) | |
| { | |
| Object left = lhs.evaluate(context, pos, len); | |
| Object right = rhs.evaluate(context, pos, len); | |
| /* | |
| * If both objects to be compared are node-sets, then the comparison | |
| * will be true if and only if there is a node in the first node-set and | |
| * a node in the second node-set such that the result of performing the | |
| * comparison on the string-values of the two nodes is true. | |
| */ | |
| boolean flns = left instanceof Collection; | |
| boolean frns = right instanceof Collection; | |
| if (flns && frns) | |
| { | |
| Collection lns = (Collection) left; | |
| Collection rns = (Collection) right; | |
| if (lns.isEmpty()) | |
| { | |
| return false; | |
| } | |
| boolean all = true; | |
| for (Iterator i = lns.iterator(); i.hasNext(); ) | |
| { | |
| Node ltest = (Node) i.next(); | |
| for (Iterator j = rns.iterator(); j.hasNext(); ) | |
| { | |
| Node rtest = (Node) j.next(); | |
| if (ltest == rtest || ltest.equals(rtest)) | |
| { | |
| // much shorter | |
| if (!invert) | |
| { | |
| return true; | |
| } | |
| } | |
| else if (stringValue(ltest).equals(stringValue(rtest))) | |
| { | |
| if (!invert) | |
| { | |
| return true; | |
| } | |
| } | |
| else | |
| { | |
| all = false; | |
| } | |
| } | |
| } | |
| return all; | |
| } | |
| /* | |
| * If one object to be compared is a node-set and the other is a number, | |
| * then the comparison will be true if and only if there is a node in | |
| * the node-set such that the result of performing the comparison on the | |
| * number to be compared and on the result of converting the | |
| * string-value of that node to a number using the number function is | |
| * true. | |
| */ | |
| boolean fln = left instanceof Double; | |
| boolean frn = right instanceof Double; | |
| if ((flns && frn) || (frns && fln)) | |
| { | |
| Collection ns = flns ? (Collection) left : (Collection) right; | |
| double n = fln ? ((Double) left).doubleValue() : | |
| ((Double) right).doubleValue(); | |
| boolean all = true; | |
| for (Iterator i = ns.iterator(); i.hasNext(); ) | |
| { | |
| Node test = (Node) i.next(); | |
| double nn = _number(context, stringValue(test)); | |
| if (nn == n) | |
| { | |
| if (!invert) | |
| { | |
| return true; | |
| } | |
| } | |
| else | |
| { | |
| all = false; | |
| } | |
| } | |
| return invert ? all : false; | |
| } | |
| /* | |
| * If one object to be compared is a node-set and the other is a | |
| * string, then the comparison will be true if and only if there is a | |
| * node in the node-set such that the result of performing the | |
| * comparison on the string-value of the node and the other string is | |
| * true. | |
| */ | |
| boolean fls = left instanceof String; | |
| boolean frs = right instanceof String; | |
| if ((flns && frs) || (frns && fls)) | |
| { | |
| Collection ns = flns ? (Collection) left : (Collection) right; | |
| String s = fls ? (String) left : (String) right; | |
| boolean all = true; | |
| for (Iterator i = ns.iterator(); i.hasNext(); ) | |
| { | |
| Node test = (Node) i.next(); | |
| if (stringValue(test).equals(s)) | |
| { | |
| if (!invert) | |
| { | |
| return true; | |
| } | |
| } | |
| else | |
| { | |
| all = false; | |
| } | |
| } | |
| return invert ? all : false; | |
| } | |
| /* | |
| * If one object to be compared is a node-set and the other is a | |
| * boolean, then the comparison will be true if and only if the result | |
| * of performing the comparison on the boolean and on the result of | |
| * converting the node-set to a boolean using the boolean function is | |
| * true. | |
| */ | |
| boolean flb = left instanceof Boolean; | |
| boolean frb = right instanceof Boolean; | |
| if ((flns && frb) || (frns && flb)) | |
| { | |
| Collection ns = flns ? (Collection) left : (Collection) right; | |
| boolean b = flb ? ((Boolean) left).booleanValue() : | |
| ((Boolean) right).booleanValue(); | |
| return _boolean(context, ns) == b; | |
| } | |
| /* | |
| * If at least one object to be compared is a boolean, then each object | |
| * to be compared is converted to a boolean as if by applying the | |
| * boolean function. | |
| */ | |
| if (flb || frb) | |
| { | |
| boolean lb = flb ? ((Boolean) left).booleanValue() : | |
| _boolean(context, left); | |
| boolean rb = frb ? ((Boolean) right).booleanValue() : | |
| _boolean(context, right); | |
| return lb == rb; | |
| } | |
| /* | |
| * Otherwise, if at least one object to be compared is | |
| * a number, then each object to be compared is converted to a number as | |
| * if by applying the number function. | |
| */ | |
| if (fln || frn) | |
| { | |
| double ln = fln ? ((Double) left).doubleValue() : | |
| _number(context, left); | |
| double rn = frn ? ((Double) right).doubleValue() : | |
| _number(context, right); | |
| return ln == rn; | |
| } | |
| /* | |
| * Otherwise, both objects to be | |
| * compared are converted to strings as if by applying the string | |
| * function. | |
| */ | |
| String ls = fls ? (String) left : _string(context, left); | |
| String rs = frs ? (String) right : _string(context, right); | |
| return ls.equals(rs); | |
| } | |
| public Expr clone(Object context) | |
| { | |
| return new EqualityExpr(lhs.clone(context), rhs.clone(context), invert); | |
| } | |
| public boolean references(QName var) | |
| { | |
| return (lhs.references(var) || rhs.references(var)); | |
| } | |
| public String toString() | |
| { | |
| if (invert) | |
| { | |
| return lhs + " != " + rhs; | |
| } | |
| else | |
| { | |
| return lhs + " = " + rhs; | |
| } | |
| } | |
| } |