opennlp.tools.util.ObjectStreamUtils 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 opennlp.tools.util;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
public class ObjectStreamUtils {
/**
* Creates an {@link ObjectStream} form an array.
*
* @param
* @param array
*
* @return the object stream over the array elements
*/
@SafeVarargs
public static ObjectStream createObjectStream(final T... array) {
return new ObjectStream() {
private int index = 0;
public T read() {
if (index < array.length)
return array[index++];
else
return null;
}
public void reset() {
index = 0;
}
public void close() {
}
};
}
/**
* Creates an {@link ObjectStream} form a collection.
*
* @param
* @param collection
*
* @return the object stream over the collection elements
*/
public static ObjectStream createObjectStream(final Collection collection) {
return new ObjectStream() {
private Iterator iterator = collection.iterator();
public T read() {
if (iterator.hasNext())
return iterator.next();
else
return null;
}
public void reset() {
iterator = collection.iterator();
}
public void close() {
}
};
}
/**
* Creates a single concatenated ObjectStream from multiple individual
* ObjectStreams with the same type.
*
* @param streams
* @return
*/
@SafeVarargs
public static ObjectStream createObjectStream(final ObjectStream... streams) {
for (ObjectStream stream : streams) {
if (stream == null)
throw new NullPointerException("stream cannot be null");
}
return new ObjectStream() {
private int streamIndex = 0;
public T read() throws IOException {
T object = null;
while (streamIndex < streams.length && object == null) {
object = streams[streamIndex].read();
if (object == null)
streamIndex++;
}
return object;
}
public void reset() throws IOException, UnsupportedOperationException {
streamIndex = 0;
for (ObjectStream stream : streams) {
stream.reset();
}
}
public void close() throws IOException {
for (ObjectStream stream : streams) {
stream.close();
}
}};
}
}