org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/console/ConsoleDocument.java

/*******************************************************************************
 * Copyright (c) 2008-2010 Sonatype, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *      Sonatype, Inc. - initial API and implementation
 *******************************************************************************/

package org.eclipse.m2e.core.ui.internal.console;

/**
 * Simple circular buffer that stores a fix number of lines.
 */
// TODO consider use standard ConsoleDocument
public class ConsoleDocument {
  public static final int COMMAND = 0; // command text

  public static final int MESSAGE = 1; // message received

  public static final int ERROR = 2; // error received

  public static final int STATUS = 3; // status text

  public static final int DELIMITER = 4; // delimiter text between runs

  private int[] lineTypes;

  private String[] lines;

  private int writeIndex = 0;

  private int readIndex = 0;

  private static final int BUFFER_SIZE = 200;

  protected static class ConsoleLine {
    public String line;

    public int type;

    ConsoleLine(String line, int type) {
      this.line = line;
      this.type = type;
    }
  }

  /**
   * Creates an empty console document.
   */
  public ConsoleDocument() {
  }

  /**
   * Clears the console document.
   */
  public void clear() {
    lineTypes = null;
    lines = null;
    writeIndex = 0;
    readIndex = 0;
  }

  /**
   * Appends a line of the specified type to the end of the console.
   */
  public void appendConsoleLine(int type, String line) {
    if(lines == null) {
      lines = new String[BUFFER_SIZE];
      lineTypes = new int[BUFFER_SIZE];
    }
    lines[writeIndex] = line;
    lineTypes[writeIndex] = type;

    if(++writeIndex >= BUFFER_SIZE) {
      writeIndex = 0;
    }
    if(writeIndex == readIndex) {
      if(++readIndex >= BUFFER_SIZE) {
        readIndex = 0;
      }
    }
  }

  public ConsoleLine[] getLines() {
    if(isEmpty())
      return new ConsoleLine[0];
    ConsoleLine[] docLines = new ConsoleLine[readIndex > writeIndex ? BUFFER_SIZE : writeIndex];
    int index = readIndex;
    for(int i = 0; i < docLines.length; i++ ) {
      docLines[i] = new ConsoleLine(lines[index], lineTypes[index]);
      if(++index >= BUFFER_SIZE) {
        index = 0;
      }
    }
    return docLines;
  }

  public boolean isEmpty() {
    return writeIndex == readIndex;
  }
}