| /******************************************************************************* |
| * Copyright (c) 2005, 2009 Andrea Bittau, University College London, and others |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Andrea Bittau - initial API and implementation from the PsychoPath XPath 2.0 |
| * Jesper Steen Moeller - bug 285145 - implement full arity checking |
| *******************************************************************************/ |
| |
| package org.eclipse.wst.xml.xpath2.processor.internal.function; |
| |
| import org.eclipse.wst.xml.xpath2.processor.DynamicError; |
| import org.eclipse.wst.xml.xpath2.processor.ResultSequence; |
| import org.eclipse.wst.xml.xpath2.processor.ResultSequenceFactory; |
| import org.eclipse.wst.xml.xpath2.processor.internal.*; |
| import org.eclipse.wst.xml.xpath2.processor.internal.types.*; |
| |
| import java.math.BigInteger; |
| import java.util.*; |
| |
| /** |
| * |
| * <p> |
| * String comparison function. |
| * </p> |
| * |
| * <p> |
| * Usage: fn:compare($comparand1 as xs:string?, $comparand2 as xs:string?) as |
| * xs:integer? |
| * </p> |
| * |
| * <p> |
| * This class returns -1, 0, or 1, depending on whether the value of $comparand1 |
| * is respectively less than, equal to, or greater than the value of |
| * $comparand2. |
| * </p> |
| * |
| * <p> |
| * If the value of $comparand2 begins with a string that is equal to the value |
| * of $comparand1 (according to the collation that is used) and has additional |
| * code points following that beginning string, then the result is -1. If the |
| * value of $comparand1 begins with a string that is equal to the value of |
| * $comparand2 and has additional code points following that beginning string, |
| * then the result is 1. |
| * </p> |
| * |
| * <p> |
| * If either argument is the empty sequence, the result is the empty sequence. |
| * </p> |
| */ |
| public class FnCompare extends Function { |
| private static Collection _expected_args = null; |
| |
| /** |
| * Constructor of FnCompare. |
| */ |
| public FnCompare() { |
| // XXX: This should be 2-3 when compare learns how to deal with collations |
| super(new QName("compare"), 2); |
| } |
| |
| /** |
| * Evaluate the arguments. |
| * |
| * @param args |
| * is evaluated. |
| * @throws DynamicError |
| * Dynamic error. |
| * @return The evaluation of the comparison of the arguments. |
| */ |
| @Override |
| public ResultSequence evaluate(Collection args) throws DynamicError { |
| return compare(args); |
| } |
| |
| /** |
| * Compare the arguments. |
| * |
| * @param args |
| * are compared. |
| * @throws DynamicError |
| * Dynamic error. |
| * @return The result of the comparison of the arguments. |
| */ |
| public static ResultSequence compare(Collection args) throws DynamicError { |
| Collection cargs = Function.convert_arguments(args, expected_args()); |
| |
| ResultSequence rs = ResultSequenceFactory.create_new(); |
| |
| Iterator argiter = cargs.iterator(); |
| ResultSequence arg1 = (ResultSequence) argiter.next(); |
| if (arg1.empty()) |
| return rs; |
| ResultSequence arg2 = (ResultSequence) argiter.next(); |
| if (arg2.empty()) |
| return rs; |
| |
| XSString xstr1 = (XSString) arg1.first(); |
| XSString xstr2 = (XSString) arg2.first(); |
| |
| // XXX collations!!! |
| int ret = xstr1.value().compareTo(xstr2.value()); |
| |
| if (ret == 0) |
| rs.add(new XSInteger(BigInteger.valueOf(0))); |
| else if (ret < 0) |
| rs.add(new XSInteger(BigInteger.valueOf(-1))); |
| else |
| rs.add(new XSInteger(BigInteger.valueOf(1))); |
| |
| return rs; |
| } |
| |
| /** |
| * Calculate the expected arguments. |
| * |
| * @return The expected arguments. |
| */ |
| public static Collection expected_args() { |
| if (_expected_args == null) { |
| _expected_args = new ArrayList(); |
| SeqType arg = new SeqType(new XSString(), SeqType.OCC_QMARK); |
| _expected_args.add(arg); |
| _expected_args.add(arg); |
| } |
| |
| return _expected_args; |
| } |
| } |