com.profesorfalken.jpowershell.PowerShellCommandProcessor Maven / Gradle / Ivy
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/*
* Copyright 2016-2018 Javier Garcia Alonso.
*
* 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.profesorfalken.jpowershell;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.concurrent.Callable;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Processor used to send commands to PowerShell console.
* It works as an independent thread and its results are collected using the Future interface.
*
* @author Javier Garcia Alonso
*/
class PowerShellCommandProcessor implements Callable {
private static final String CRLF = "\r\n";
private final BufferedReader reader;
private boolean closed = false;
private final boolean scriptMode;
private final int waitPause;
/**
* Constructor that takes the output and the input of the PowerShell session
*
* @param name the name of the CommandProcessor
* @param inputStream the stream needed to read the command output
* @param waitPause long the wait pause in milliseconds
* @param scriptMode boolean indicates if the command executes a script
*/
public PowerShellCommandProcessor(String name, InputStream inputStream, int waitPause, boolean scriptMode) {
this.reader = new BufferedReader(new InputStreamReader(
inputStream));
this.waitPause = waitPause;
this.scriptMode = scriptMode;
}
/**
* Calls the command and returns its output
*
* @return String output of call
* @throws InterruptedException error when reading data
*/
public String call() throws InterruptedException {
StringBuilder powerShellOutput = new StringBuilder();
try {
if (startReading()) {
readData(powerShellOutput);
}
} catch (IOException ioe) {
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE, "Unexpected error reading PowerShell output", ioe);
return ioe.getMessage();
}
//Remove last CRLF from result
return powerShellOutput.toString().replaceAll("\\s+$", "");
}
//Reads all data from output
private void readData(StringBuilder powerShellOutput) throws IOException {
String line;
while (null != (line = this.reader.readLine())) {
//In the case of script mode it finish when the last line is read
if (this.scriptMode) {
if (line.equals(PowerShell.END_SCRIPT_STRING)) {
break;
}
}
powerShellOutput.append(line).append(CRLF);
//When not in script mode, it exits when the command is finished
if (!this.scriptMode) {
try {
if (this.closed || !canContinueReading()) {
break;
}
} catch (InterruptedException ex) {
Logger.getLogger(PowerShellCommandProcessor.class.getName()).log(Level.SEVERE, "Error executing command and reading result", ex);
}
}
}
}
//Checks when we can start reading the output. Timeout if it takes too long in order to avoid hangs
private boolean startReading() throws IOException, InterruptedException {
//If the reader is not ready, gives it some milliseconds
while (!this.reader.ready()) {
Thread.sleep(this.waitPause);
if (this.closed) {
return false;
}
}
return true;
}
//Checks when we the reader can continue to read.
private boolean canContinueReading() throws IOException, InterruptedException {
//If the reader is not ready, gives it some milliseconds
//It is important to do that, because the ready method guarantees that the readline will not be blocking
if (!this.reader.ready()) {
Thread.sleep(this.waitPause);
}
//If not ready yet, wait a moment to make sure it is finished
if (!this.reader.ready()) {
Thread.sleep(50);
}
return this.reader.ready();
}
/**
* Closes the command processor, canceling the current work if not finish
*/
public void close() {
this.closed = true;
}
}