diff options
Diffstat (limited to 'gnu/xml/xpath/EqualityExpr.java')
-rw-r--r-- | gnu/xml/xpath/EqualityExpr.java | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/gnu/xml/xpath/EqualityExpr.java b/gnu/xml/xpath/EqualityExpr.java new file mode 100644 index 000000000..bedf1e974 --- /dev/null +++ b/gnu/xml/xpath/EqualityExpr.java @@ -0,0 +1,258 @@ +/* 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., 59 Temple Place, Suite 330, Boston, MA +02111-1307 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 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; + 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 false; + } + /* + * 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 String toString() + { + if (invert) + { + return lhs + " != " + rhs; + } + else + { + return lhs + " = " + rhs; + } + } + +} |