| // Copyright 2011 Google Inc. All Rights Reserved. |
| // |
| // 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. |
| |
| package com.google.enterprise.adaptor; |
| |
| import java.io.*; |
| |
| /** |
| * OutputStream that passes all calls to the {@code OutputStream} provided by |
| * {@link #retrieveOs}, but calls {@code retrieveOs()} only once needed. |
| */ |
| abstract class AbstractLazyOutputStream extends OutputStream { |
| private OutputStream os; |
| |
| @Override |
| public void close() throws IOException { |
| loadOs(); |
| os.close(); |
| } |
| |
| @Override |
| public void flush() throws IOException { |
| loadOs(); |
| os.flush(); |
| } |
| |
| @Override |
| public void write(byte[] b, int off, int len) throws IOException { |
| loadOs(); |
| os.write(b, off, len); |
| } |
| |
| @Override |
| public void write(byte[] b) throws IOException { |
| write(b, 0, b.length); |
| } |
| |
| @Override |
| public void write(int b) throws IOException { |
| loadOs(); |
| os.write(b); |
| } |
| |
| protected void loadOs() throws IOException { |
| if (os == null) { |
| os = retrieveOs(); |
| } |
| } |
| |
| /** |
| * Retrieve the real {@code OutputStream}. Will only be called once. |
| */ |
| protected abstract OutputStream retrieveOs() throws IOException; |
| } |