/*
* 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.jena.shared.wg;
import java.io.*;
/**
*In test cases we cannot open all the input files
* while creating the test suite, but must defer the
* opening until the test is actually run.
*/
abstract class LazyInputStream extends InputStream {
private InputStream underlying;
abstract InputStream open() throws IOException;
boolean connect() throws IOException {
if ( underlying != null )
return true;
else {
underlying = open();
}
return underlying != null;
}
@Override
public int read() throws IOException {
if (underlying == null)
underlying = open();
return underlying.read();
}
@Override
public void close() throws IOException {
if (underlying != null) {
underlying.close();
underlying = null;
}
}
}