org.apache.openjpa.lib.meta.MetaDataIteratorChain Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.openjpa.lib.meta;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
/**
* Metadata iterator that combines several iterators.
*
* @author Abe White
*/
public class MetaDataIteratorChain implements MetaDataIterator {
private List _itrs = null;
private int _cur = -1;
private MetaDataIterator _itr = null;
/**
* Default constructor.
*/
public MetaDataIteratorChain() {
}
/**
* Combine two iterators.
*/
public MetaDataIteratorChain(MetaDataIterator itr1, MetaDataIterator itr2) {
_itrs = new ArrayList(2);
_itrs.add(itr1);
_itrs.add(itr2);
}
/**
* Add an iterator to the chain.
*/
public void addIterator(MetaDataIterator itr) {
if (_cur != -1)
throw new IllegalStateException();
if (_itrs == null)
_itrs = new ArrayList(4);
_itrs.add(itr);
}
public boolean hasNext() throws IOException {
if (_itrs == null)
return false;
if (_cur == -1)
_cur = 0;
MetaDataIterator itr;
for (; _cur < _itrs.size(); _cur++) {
itr = (MetaDataIterator) _itrs.get(_cur);
if (itr.hasNext()) {
_itr = itr;
return true;
}
}
_itr = null;
return false;
}
public Object next() throws IOException {
if (!hasNext())
throw new NoSuchElementException();
return _itr.next();
}
public InputStream getInputStream() throws IOException {
if (_itr == null)
throw new IllegalStateException();
return _itr.getInputStream();
}
public File getFile() throws IOException {
if (_itr == null)
throw new IllegalStateException();
return _itr.getFile();
}
public void close() {
if (_itrs != null) {
for(MetaDataIterator mdi: _itrs) {
mdi.close();
}
}
}
}