org.eclipse.ui.console/src/org/eclipse/ui/console/IOConsole.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.ui.console;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.ui.WorkbenchEncoding;
import org.eclipse.ui.internal.console.IOConsolePage;
import org.eclipse.ui.internal.console.IOConsolePartitioner;
import org.eclipse.ui.part.IPageBookViewPage;

/**
 * A console that displays text from I/O streams. An I/O console can have multiple
 * output streams connected to it and provides one input stream connected to the
 * keyboard.
 * <p>
 * Clients may instantiate and subclass this class.
 * </p>
 * @since 3.1
 */
public class IOConsole extends TextConsole {
	/**
	 * The document partitioner
	 */
    private IOConsolePartitioner partitioner;
    
    /**
     * The stream from which user input may be read
     */
    private IOConsoleInputStream inputStream;
        
    /**
     * A collection of open streams connected to this console.
     */
    private List openStreams;

    /**
     * The encoding used to for displaying console output.
     */
    private String fEncoding = WorkbenchEncoding.getWorkbenchDefaultEncoding();

    
    /**
     * Constructs a console with the given name, type, image, and lifecycle, with the
     * workbench's default encoding.
     * 
     * @param name name to display for this console
     * @param consoleType console type identifier or <code>null</code>
     * @param imageDescriptor image to display for this console or <code>null</code>
     * @param autoLifecycle whether lifecycle methods should be called automatically
     *  when this console is added/removed from the console manager
     */
    public IOConsole(String name, String consoleType, ImageDescriptor imageDescriptor, boolean autoLifecycle) {
        this(name, consoleType, imageDescriptor, null, autoLifecycle);
    }

    /**
     * Constructs a console with the given name, type, image, encoding and lifecycle.
     * 
     * @param name name to display for this console
     * @param consoleType console type identifier or <code>null</code>
     * @param imageDescriptor image to display for this console or <code>null</code>
     * @param autoLifecycle whether lifecycle methods should be called automatically
     *  when this console is added/removed from the console manager
     */
    public IOConsole(String name, String consoleType, ImageDescriptor imageDescriptor, String encoding, boolean autoLifecycle) {
        super(name, consoleType, imageDescriptor, autoLifecycle);
        if (encoding != null) {
            fEncoding = encoding;
        }
        openStreams = new ArrayList();
        inputStream = new IOConsoleInputStream(this);
        openStreams.add(inputStream);
        partitioner = new IOConsolePartitioner(inputStream, this);
        partitioner.connect(getDocument());
    }
    
    /**
     * Constructs a console with the given name, type, and image with the workbench's
     * default encoding. Lifecycle methods will be called when this console is
     * added/removed from the console manager.
     * 
     * @param name name to display for this console
     * @param consoleType console type identifier or <code>null</code>
     * @param imageDescriptor image to display for this console or <code>null</code>
     */
    public IOConsole(String name, String consoleType, ImageDescriptor imageDescriptor) {
        this(name, consoleType, imageDescriptor, true);
    }    
    
    /**
     * Constructs a console with the given name and image. Lifecycle methods
     * will be called when this console is added/removed from the console manager.
     * This console will have an unspecified (<code>null</code>) type.
     * 
     * @param name name to display for this console
     * @param imageDescriptor image to display for this console or <code>null</code>
     */
    public IOConsole(String name, ImageDescriptor imageDescriptor) {
        this(name, null, imageDescriptor);
    }
    
    /* (non-Javadoc)
     * @see org.eclipse.ui.console.IConsole#createPage(org.eclipse.ui.console.IConsoleView)
     */
    public IPageBookViewPage createPage(IConsoleView view) {
        return new IOConsolePage(this, view);
    }
    
    /**
     * Creates and returns a new output stream which may be used to write to this console.
     * A console may be connected to more than one output stream at once. Clients are
     * responsible for closing any output streams created on this console.
     * 
     * @return a new output stream connected to this console
     */
    public IOConsoleOutputStream newOutputStream() {
        IOConsoleOutputStream outputStream = new IOConsoleOutputStream(this);
        outputStream.setEncoding(fEncoding);
        synchronized(openStreams) {
            openStreams.add(outputStream);
        }
        return outputStream;
    }
    
    /**
     * Returns the input stream connected to the keyboard.
     * 
     * @return the input stream connected to the keyboard.
     */
    public IOConsoleInputStream getInputStream() {
        return inputStream;
    }

    /**
     * Returns this console's document partitioner.
     * 
     * @return this console's document partitioner
     */
    protected IConsoleDocumentPartitioner getPartitioner() {
        return partitioner;
    }

	/**
	 * Returns the maximum number of characters that the console will display at
	 * once. This is analagous to the size of the text buffer this console
	 * maintains.
	 * 
	 * @return the maximum number of characters that the console will display
	 */
	public int getHighWaterMark() {
	    return partitioner.getHighWaterMark();
	}
	
	/**
	 * Returns the number of characters that will remain in this console
	 * when its high water mark is exceeded.
	 *  
	 * @return the number of characters that will remain in this console
	 *  when its high water mark is exceeded
	 */
	public int getLowWaterMark() {
		return partitioner.getLowWaterMark();
	}
	
	/**
	 * Sets the text buffer size for this console. The high water mark indicates
	 * the maximum number of characters stored in the buffer. The low water mark
	 * indicates the number of characters remaining in the buffer when the high
	 * water mark is exceeded.
	 * 
	 * @param low the number of characters remaining in the buffer when the high
	 *  water mark is exceeded (if -1 the console does not limit output)
	 * @param high the maximum number of characters this console will cache in
	 *  its text buffer (if -1 the console does not limit output)
	 * @exception IllegalArgumentException if low >= high & low != -1
	 */
	public void setWaterMarks(int low, int high) {
        if (low >= 0) {
    	    if (low >= high) {
    	        throw new IllegalArgumentException("High water mark must be greater than low water mark"); //$NON-NLS-1$
    	    }
        }
		partitioner.setWaterMarks(low, high);
	}

    /**
     * Check if all streams connected to this console are closed. If so,
     * notifiy the partitioner that this console is finished. 
     */
    private void checkFinished() {
        if (openStreams.isEmpty()) {
            partitioner.streamsClosed();
        }
    }
    
    /**
     * Notification that an output stream connected to this console has been closed.
     * 
     * @param stream stream that closed
     */
    void streamClosed(IOConsoleOutputStream stream) {
    	synchronized (openStreams) {
            openStreams.remove(stream);
            checkFinished();
		}
    }
    
    /**
     * Notification that the input stream connected to this console has been closed.
     * 
     * @param stream stream that closed
     */
    void streamClosed(IOConsoleInputStream stream) {
    	synchronized (openStreams) {
            openStreams.remove(stream);
            checkFinished();
		}
    }
    
    /* (non-Javadoc)
     * @see org.eclipse.ui.console.TextConsole#clearConsole()
     */
    public void clearConsole() {
        if (partitioner != null) {
            partitioner.clearBuffer();
        }
    }
    
    /**
     * Disposes this console.
     */
    protected void dispose() {
        super.dispose();
        partitioner.disconnect();
        try {
            inputStream.close();
        } catch (IOException ioe) {
        }
        inputStream = null;
    }
}