/*
* @(#)$Id: AbstractSequence.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.dm.value;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;
import xbird.util.struct.ThreeLogic;
import xbird.util.xml.SAXWriter;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.ser.SAXSerializer;
import xbird.xquery.dm.value.sequence.AtomizedSequence;
import xbird.xquery.meta.*;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public abstract class AbstractSequence<E extends Item> implements Sequence<E> {
private static final long serialVersionUID = 1L;
protected final DynamicContext _dynEnv;
public AbstractSequence(DynamicContext dynEnv) {
this._dynEnv = dynEnv;
}
/** -1(nil), 0(empty), 1(not empty) */
private ThreeLogic isEmptyFlag = ThreeLogic.NIL;
public boolean isEmpty() {
if(isEmptyFlag != ThreeLogic.NIL) {
return isEmptyFlag == ThreeLogic.TRUE;
}
final boolean empty = isEmpty(iterator());//FIXME
isEmptyFlag = (empty ? ThreeLogic.TRUE : ThreeLogic.FALSE);
return empty;
}
private boolean isEmpty(IFocus<E> focus) {
return (focus.getContextPosition() == 0) ? !focus.hasNext() : true;
}
public IFocus<E> iterator() {
return new Focus<E>(this, _dynEnv);
}
public Sequence<? extends Item> atomize(DynamicContext dynEnv) {
return (Sequence<? extends Item>) AtomizedSequence.wrap(this, dynEnv);
}
public List<E> materialize() {
final List<E> vs = new ArrayList<E>(512);
final IFocus<E> itor = iterator();
for(E it : itor) {
vs.add(it);
}
itor.closeQuietly();
return vs;
}
@Override
public String toString() {
final StringWriter sw = new StringWriter();
final SAXSerializer ser = new SAXSerializer(new SAXWriter(sw), sw);
try {
ser.emit(this);
} catch (XQueryException e) {
return "failed at " + e.getStackTrace()[1] + "!\n" + e.getMessage();
}
return sw.toString();
}
}