/*
* @(#)$Id: Compare.java 3619 2008-03-26 07:23:03Z yui $
*
* Copyright 2006-2008 Makoto YUI
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.xquery.func.string;
import java.text.Collator;
import xbird.util.resource.CollationUtils;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.literal.XInteger;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.func.BuiltInFunction;
import xbird.xquery.func.FunctionSignature;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.type.Type;
import xbird.xquery.type.TypeRegistry;
import xbird.xquery.type.xs.StringType;
/**
* fn:compare.
* <DIV lang="en">
* Returns -1, 0, or 1, depending on whether the value of the $comparand1 is respectively
* less than, equal to, or greater than the value of $comparand2, according to the rules
* of the collation that is used.
* <ul>
* <li>fn:compare($comparand1 as xs:string?, $comparand2 as xs:string?) as xs:integer?</li>
* <li>fn:compare($comparand1 as xs:string?, $comparand2 as xs:string?, $collation as xs:string) as xs:integer?</li>
* </ul>
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-compare
*/
public final class Compare extends BuiltInFunction {
private static final long serialVersionUID = 3703985794159908946L;
public static final String SYMBOL = "fn:compare";
public Compare() {
super(SYMBOL, TypeRegistry.safeGet("xs:integer?"));
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] t = new FunctionSignature[2];
Type str = TypeRegistry.safeGet("xs:string?");
t[0] = new FunctionSignature(getName(), new Type[] { str, str });
t[1] = new FunctionSignature(getName(), new Type[] { str, str, StringType.STRING });
return t;
}
public Sequence eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv)
throws XQueryException {
assert (argv != null);
Item firstItem = argv.getItem(0);
if(firstItem.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
Item secondItem = argv.getItem(1);
if(secondItem.isEmpty()) {
return ValueSequence.EMPTY_SEQUENCE;
}
String comparand1 = firstItem.stringValue();
String comparand2 = secondItem.stringValue();
final int cmp;
final int arglen = argv.size();
assert (arglen == 2 || arglen == 3);
if(arglen == 3) {
Item thirdItem = argv.getItem(2);
String collation = thirdItem.stringValue();
Collator collator = CollationUtils.resolve(collation, dynEnv.getStaticContext());
cmp = collator.compare(comparand1, comparand2);
} else {
cmp = comparand1.compareTo(comparand2);
}
return cmp == 0 ? XInteger.valueOf(0) : (cmp > 0 ? XInteger.valueOf(1)
: XInteger.valueOf(-1));
}
}