bassistance.de

Another fragment that turned out to be useless for the project, but may come handy in the future. A port to JavaScript should be easy enough, too:

import java.util.ArrayList;
import java.util.List;

public class CommandStack {

	/**
	 * Implement for each individual change that can occur in an editor.
	 *


	 * Both {@link #execute()} and {@link #undo()} should fire property change
	 * events for notifying the editor of an update.
	 */
	public static abstract class Command {

		private String name;

		public Command(String name) {
			this.name = name;
		}

		@Override
		public String toString() {
			return name;
		}

		/**
		 * Implements the actual change.
		 *


		 * Any state-saving for {@link #undo()}
		 * has to occur elsewhere, eg. in the constructor.
		 */
		public abstract void execute();

		/**
		 * Reverts any changes applied by {@link #execute()}.
		 */
		public abstract void undo();

	}

	private final List commands = new ArrayList();
	private int currentLocation = -1;
	private int saveLocation = currentLocation;

	public void add(Command command) {
		clearInFrontOfCurrent();
		command.execute();
		commands.add(command);
		currentLocation++;
	}

	public void undo() {
		commands.get(currentLocation).undo();
		currentLocation--;
	}

	public boolean undoEnabled() {
		return currentLocation >= 0;
	}

	public void redo() {
		currentLocation++;
		commands.get(currentLocation).execute();
	}

	public boolean redoEnabled() {
		return currentLocation < commands.size() - 1;
	}

	public boolean dirty() {
		return currentLocation != saveLocation;
	}

	private void clearInFrontOfCurrent() {
		while (currentLocation < commands.size() - 1) {
			commands.remove(currentLocation + 1);
		}
	}

	public void markSaveLocation() {
		saveLocation = currentLocation;
	}

	@Override
	public String toString() {
		return commands.toString();
	}

}

And to illustrate the usage, the JUnit test:

import junit.framework.TestCase;

public class CommandStackTest extends TestCase {

	CommandStack stack = new CommandStack();

	private String name;
	private int age;

	class EditName extends Command {

		private String oldName = name;
		private String newName;

		public EditName(String newName) {
			super("Update name to " + newName);
			this.newName = newName;
		}

		public void execute() {
			name = newName;
		}

		public void undo() {
			name = oldName;
		}
	};

	class EditAge extends Command {

		private int oldAge = age;
		private int newAge;

		public EditAge(int newAge) {
			super("Update age to " + newAge);
			this.newAge = newAge;
		}

		public void execute() {
			age = newAge;
		}

		public void undo() {
			age = oldAge;
		}
	};

	public void test_basics() {
		assertNull(name);
		assertEquals(0, age);
		assertFalse(stack.dirty());
		assertFalse(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.add(new EditName("Peter"));

		assertTrue(stack.dirty());
		assertEquals("Peter", name);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.undo();

		assertNull(name);
		assertFalse(stack.undoEnabled());
		assertTrue(stack.redoEnabled());
		assertFalse(stack.dirty());

		stack.redo();

		assertTrue(stack.dirty());
		assertEquals("Peter", name);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.markSaveLocation();

		assertFalse(stack.dirty());
		assertEquals("Peter", name);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.add(new EditAge(10));

		assertTrue(stack.dirty());
		assertEquals(10, age);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.undo();

		assertFalse(stack.dirty());
		assertEquals(0, age);
		assertTrue(stack.undoEnabled());
		assertTrue(stack.redoEnabled());

		stack.add(new EditName("Pan"));

		assertTrue(stack.dirty());
		assertEquals("Pan", name);
		assertEquals(0, age);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());

		stack.undo();
		stack.undo();

		assertTrue(stack.dirty());
		assertNull(name);
		assertEquals(0, age);
		assertFalse(stack.undoEnabled());
		assertTrue(stack.redoEnabled());

		stack.redo();
		stack.redo();

		assertTrue(stack.dirty());
		assertEquals("Pan", name);
		assertEquals(0, age);
		assertTrue(stack.undoEnabled());
		assertFalse(stack.redoEnabled());
	}

}

This is for the archive and due to lack of useful tutorials on writing custom search pages in your own Eclipse plugin. It turned out that the default text search is good enough for my purposes, so I’ll stick it here as a future reference.

To start, your Eclipse plugin needs to add org.eclipse.search as a dependency, and, if you don’t have it already, org.eclipse.jface.text, too. With that, the Require-Bundle part of your MANIFEST.MF should look something like this:

Require-Bundle: org.eclipse.ui,
org.eclipse.core.runtime,
org.eclipse.ui.views,
org.eclipse.core.resources,
org.eclipse.ui.ide,
org.eclipse.ui.workbench.texteditor,
org.eclipse.text,
org.eclipse.ui.editors,
org.eclipse.search,
org.eclipse.jface.text

Next, we’ll specify the extension for our custom search page, using the plugin.xml editor or just pasting and modifying this snippet:

<extension point="org.eclipse.search.searchPages">
  <page
    class="com.acm.your.product.CustomSearchPage"
    id="yourplugin.page1"
    label="Your Custom Search, rename this">
  </page>
</extension>

And the actual implementation, providing a textfield as input, initialized with whatever text selection is currently active (thats where the org.eclipse.jface.text dependency comes from), and doing a text search across the full workspace:

package com.acm.your.product;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.dialogs.DialogPage;
import org.eclipse.jface.text.TextSelection;
import org.eclipse.search.ui.ISearchPage;
import org.eclipse.search.ui.ISearchPageContainer;
import org.eclipse.search.ui.NewSearchUI;
import org.eclipse.search.ui.text.TextSearchQueryProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;

public class CustomSearchPage extends DialogPage implements ISearchPage {

	private String selected;
	private Text idText;

	public IdSearchPage() {
		super();
	}

	public IdSearchPage(String title) {
		super(title);
	}

	public boolean performAction() {
		if (idText.getText().length() == 0)
			return false;
		try {
			NewSearchUI.runQueryInBackground(TextSearchQueryProvider.getPreferred().createQuery(idText.getText()));
		} catch (IllegalArgumentException e) {
			throw new RuntimeException(e);
		} catch (CoreException e) {
			throw new RuntimeException(e);
		}
        return true;
	}

	public void setContainer(ISearchPageContainer container) {
		if (container.getSelection() instanceof TextSelection) {
			selected = ((TextSelection) container.getSelection()).getText();
		}
	}

	public void createControl(Composite parent) {
		GridLayout layout = new GridLayout(1, false);
		layout.horizontalSpacing = 5;
		layout.verticalSpacing = 5;
		parent.setLayout(layout);
		new Label(parent, 0).setText("Containing text:");
		idText = new Text(parent, SWT.BORDER);
		idText.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		if (selected != null) {
			idText.setText(selected);
			idText.setSelection(0, selected.length());
		}
		setControl(parent);
	}

	@Override
	public void setVisible(boolean visible) {
		super.setVisible(visible);
		idText.setFocus();
	}

}

You can also restrict the files to search by creating a list first, and pass that to the search provider:

package com.acm.your.product;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceProxy;
import org.eclipse.core.resources.IResourceProxyVisitor;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jface.dialogs.DialogPage;
import org.eclipse.jface.text.TextSelection;
import org.eclipse.search.ui.ISearchPage;
import org.eclipse.search.ui.ISearchPageContainer;
import org.eclipse.search.ui.NewSearchUI;
import org.eclipse.search.ui.text.TextSearchQueryProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;

public class CustomSearchPage2 extends DialogPage implements ISearchPage {

	private String selected;
	private Text idText;

	public IdSearchPage() {
		super();
	}

	public IdSearchPage(String title) {
		super(title);
	}

	public boolean performAction() {
		if (idText.getText().length() == 0)
			return false;
		try {
			final List files = new ArrayList();
			ResourcesPlugin.getWorkspace().getRoot().accept(new IResourceProxyVisitor() {
				public boolean visit(IResourceProxy proxy) throws CoreException {
					if (proxy.getType() == IResource.FILE) {
						IFile file = (IFile) proxy.requestResource();
			            if (file.getLocation().getFileExtension() != null && file.getLocation().getFileExtension().matches("xml|html|js|css")) {
			            	files.add(file);
			            }
			         }
			         return true;
				}
			}, IResource.DEPTH_INFINITE);
			NewSearchUI.runQueryInBackground(TextSearchQueryProvider.getPreferred().createQuery(idText.getText(), files.toArray(new IResource[0])));
		} catch (IllegalArgumentException e) {
			throw new RuntimeException(e);
		} catch (CoreException e) {
			throw new RuntimeException(e);
		}
        return true;
	}

	public void setContainer(ISearchPageContainer container) {
		if (container.getSelection() instanceof TextSelection) {
			selected = ((TextSelection) container.getSelection()).getText();
		}
	}

	public void createControl(Composite parent) {
		GridLayout layout = new GridLayout(1, false);
		layout.horizontalSpacing = 5;
		layout.verticalSpacing = 5;
		parent.setLayout(layout);
		new Label(parent, 0).setText("Containing text:");
		idText = new Text(parent, SWT.BORDER);
		idText.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		if (selected != null) {
			idText.setText(selected);
			idText.setSelection(0, selected.length());
		}
		setControl(parent);
	}

	@Override
	public void setVisible(boolean visible) {
		super.setVisible(visible);
		idText.setFocus();
	}

}

This in itself doesn’t yet provide a lot of value, but if you actually need to build a custom search, its a good start.

Roughly based on this sort-of tutorial on the Eclipse wiki.