/*
* @(#)$Id: Substring.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 xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.literal.XNumber;
import xbird.xquery.dm.value.literal.XString;
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.*;
/**
* fn:substring.
* <DIV lang="en">
* Returns the portion of the value of $sourceString beginning at the position
* indicated by the value of $startingLoc and continuing for the number of characters
* indicated by the value of $length.<br/>
* Note that the first character of a string is located at position 1, not position 0.
* <ul>
* <li>fn:substring($sourceString as xs:string?, $startingLoc as xs:double) as xs:string</li>
* <li>fn:substring($sourceString as xs:string?, $startingLoc as xs:double, $length as xs:double) as xs:string</li>
* </ul>
* </DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery-operators/#func-substring
*/
public final class Substring extends BuiltInFunction {
private static final long serialVersionUID = -7070216833028372984L;
public static final String SYMBOL = "fn:substring";
public Substring() {
super(SYMBOL, StringType.STRING);
}
protected FunctionSignature[] signatures() {
final FunctionSignature[] s = new FunctionSignature[4];
s[0] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:string?"),
DoubleType.DOUBLE });
s[1] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:string?"),
DoubleType.DOUBLE, DoubleType.DOUBLE });
// workaround
s[2] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:string?"),
NumericType.getInstance() });
s[3] = new FunctionSignature(getName(), new Type[] { TypeRegistry.safeGet("xs:string?"),
NumericType.getInstance(), NumericType.getInstance() });
return s;
}
public XString eval(Sequence<? extends Item> contextSeq, ValueSequence argv, DynamicContext dynEnv)
throws XQueryException {
final Item firstItem = argv.getItem(0);
if(firstItem.isEmpty()) {
// If the value of $sourceString is the empty sequence, the zero-length string is returned.
return XString.valueOf("");
}
final String sourceString = firstItem.stringValue();
final int maxSourceLen = sourceString.length();
final Item secItem = argv.getItem(1);
final XNumber secNum = (XNumber) secItem;
// first character of a string is located at position 1, not position 0.
final int startingLoc = Math.max(0, (int) Math.round(secNum.asDouble() - 1));
final int endingLoc;
final int arglen = argv.size();
if(arglen == 3) {
final Item thirdItem = argv.getItem(2);
final XNumber thirdNum = (XNumber) thirdItem;
final int length = (int) Math.round(thirdNum.asDouble());
endingLoc = Math.max(0, Math.min(maxSourceLen, length));
} else {
endingLoc = maxSourceLen;
}
if(endingLoc <= startingLoc) {
return XString.valueOf("");
}
final String ret = sourceString.substring(startingLoc, endingLoc);
return XString.valueOf(ret);
}
}