| /* |
| * Copyright 2003-2007 the original author or authors. |
| * |
| * 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 groovy.ui; |
| |
| import groovy.lang.Closure; |
| |
| import java.io.FilterOutputStream; |
| import java.io.IOException; |
| import java.io.PrintStream; |
| |
| /** |
| * Intercepts System.out. Implementation helper for Console.groovy. |
| * |
| * @version $Id$ |
| */ |
| public class SystemOutputInterceptor extends FilterOutputStream { |
| |
| private Closure callback; |
| |
| /** |
| * Constructor |
| * |
| * @param callback |
| * accepts a string to be sent to std out and returns a Boolean. |
| * If the return value is true, output will be sent to |
| * System.out, otherwise it will not. |
| */ |
| public SystemOutputInterceptor(final Closure callback) { |
| super(System.out); |
| |
| assert callback != null; |
| |
| this.callback = callback; |
| } |
| |
| /** |
| * Starts intercepting System.out |
| */ |
| public void start() { |
| System.setOut(new PrintStream(this)); |
| } |
| |
| /** |
| * Stops intercepting System.out, sending output to whereever it was |
| * going when this interceptor was created. |
| */ |
| public void stop() { |
| System.setOut((PrintStream) out); |
| } |
| |
| /** |
| * Intercepts output - moret common case of byte[] |
| */ |
| public void write(byte[] b, int off, int len) throws IOException { |
| Boolean result = (Boolean) callback.call(new String(b, off, len)); |
| if (result.booleanValue()) { |
| out.write(b, off, len); |
| } |
| } |
| |
| /** |
| * Intercepts output - single characters |
| */ |
| public void write(int b) throws IOException { |
| Boolean result = (Boolean) callback.call(String.valueOf((char) b)); |
| if (result.booleanValue()) { |
| out.write(b); |
| } |
| } |
| } |