/*
* Copyright 2014 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 org.springframework.yarn.boot.cli;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;
/**
* Capture output from System.out and System.err.
*
* @author Phillip Webb
*/
public class OutputCapture implements TestRule {
private CaptureOutputStream captureOut;
private CaptureOutputStream captureErr;
private ByteArrayOutputStream copy;
@Override
public Statement apply(final Statement base, Description description) {
return new Statement() {
@Override
public void evaluate() throws Throwable {
captureOutput();
try {
base.evaluate();
} finally {
releaseOutput();
}
}
};
}
protected void captureOutput() {
this.copy = new ByteArrayOutputStream();
this.captureOut = new CaptureOutputStream(System.out, this.copy);
this.captureErr = new CaptureOutputStream(System.err, this.copy);
System.setOut(new PrintStream(this.captureOut));
System.setErr(new PrintStream(this.captureErr));
}
protected void releaseOutput() {
System.setOut(this.captureOut.getOriginal());
System.setErr(this.captureErr.getOriginal());
this.copy = null;
}
public void flush() {
try {
this.captureOut.flush();
this.captureErr.flush();
} catch (IOException ex) {
// ignore
}
}
@Override
public String toString() {
flush();
return this.copy.toString();
}
private static class CaptureOutputStream extends OutputStream {
private final PrintStream original;
private final OutputStream copy;
public CaptureOutputStream(PrintStream original, OutputStream copy) {
this.original = original;
this.copy = copy;
}
@Override
public void write(int b) throws IOException {
this.copy.write(b);
this.original.write(b);
this.original.flush();
}
@Override
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
this.copy.write(b, off, len);
this.original.write(b, off, len);
}
public PrintStream getOriginal() {
return this.original;
}
@Override
public void flush() throws IOException {
this.copy.flush();
this.original.flush();
}
}
}