/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2009 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery.functions.fn;
import java.text.Collator;
import org.exist.dom.QName;
import org.exist.util.Collations;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
public class FunStartsWith extends CollatingFunction {
protected static final String FUNCTION_DESCRIPTION =
"Returns an xs:boolean indicating whether or not " +
"the value of $source starts with a sequence of collation " +
"units that provides a minimal match to the collation " +
"units of $prefix according to the collation that is used.\n\n" +
"Note:\n\n" +
"\"Minimal match\" is defined in [Unicode Collation Algorithm].\n\n" +
"If the value of $source or $prefix is the empty sequence, or " +
"contains only ignorable collation units, it is interpreted " +
"as the zero-length string.\n\nIf the value of $prefix is the " +
"zero-length string, then the function returns true. If the " +
"value of $source is the zero-length string and the value of " +
"$prefix is not the zero-length string, then the function " +
"returns false.\n\n" +
"The collation used by the invocation of this function is " +
"determined according to the rules in 7.3.1 Collations. " +
"If the specified collation does not support collation " +
"units an error may be raised [err:FOCH0004]. ";
protected static final FunctionParameterSequenceType ARG1_PARAM = new FunctionParameterSequenceType("source", Type.STRING, Cardinality.ZERO_OR_ONE, "The source string");
protected static final FunctionParameterSequenceType ARG2_PARAM = new FunctionParameterSequenceType("prefix", Type.STRING, Cardinality.ZERO_OR_ONE, "The string to determine if is a prefix of $source");
protected static final FunctionParameterSequenceType COLLATION_PARAM = new FunctionParameterSequenceType("collation-uri", Type.STRING, Cardinality.EXACTLY_ONE, "The collation URI");
protected static final FunctionReturnSequenceType RETURN_TYPE = new FunctionReturnSequenceType(Type.BOOLEAN, Cardinality.ZERO_OR_ONE, "true if $prefix is a prefix of the string $source");
public final static FunctionSignature signatures[] = {
new FunctionSignature (
new QName("starts-with", Function.BUILTIN_FUNCTION_NS),
FUNCTION_DESCRIPTION,
new SequenceType[] { ARG1_PARAM, ARG2_PARAM },
RETURN_TYPE),
new FunctionSignature (
new QName("starts-with", Function.BUILTIN_FUNCTION_NS),
FUNCTION_DESCRIPTION + THIRD_REL_COLLATION_ARG_EXAMPLE,
new SequenceType[] { ARG1_PARAM, ARG2_PARAM, COLLATION_PARAM },
RETURN_TYPE)
};
public FunStartsWith(XQueryContext context, FunctionSignature signature) {
super(context, signature);
}
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);}
if (contextItem != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());}
}
if(contextItem != null)
{contextSequence = contextItem.toSequence();}
Sequence result;
final String s1 = getArgument(0).eval(contextSequence).getStringValue();
final String s2 = getArgument(1).eval(contextSequence).getStringValue();
if(s1.length() == 0 || s2.length() == 0)
{result = Sequence.EMPTY_SEQUENCE;}
else {
final Collator collator = getCollator(contextSequence, contextItem, 3);
if(Collations.startsWith(collator, s1, s2))
{result = BooleanValue.TRUE;}
else
{result = BooleanValue.FALSE;}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
}