core/plugins/org.eclipse.dltk.debug.ui/src/org/eclipse/dltk/internal/debug/ui/ScriptDetailFormattersManager.java

package org.eclipse.dltk.internal.debug.ui;

import java.util.HashMap;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.debug.core.DebugException;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.model.IValue;
import org.eclipse.debug.ui.IValueDetailListener;
import org.eclipse.dltk.core.SimpleDLTKExtensionManager;
import org.eclipse.dltk.core.SimpleDLTKExtensionManager.ElementInfo;
import org.eclipse.dltk.debug.core.eval.IScriptEvaluationCommand;
import org.eclipse.dltk.debug.core.eval.IScriptEvaluationListener;
import org.eclipse.dltk.debug.core.eval.IScriptEvaluationResult;
import org.eclipse.dltk.debug.core.model.IScriptThread;
import org.eclipse.dltk.debug.core.model.IScriptValue;
import org.eclipse.dltk.debug.ui.DLTKDebugUIPlugin;

public class ScriptDetailFormattersManager {
	private static final String DEFAULT_FORMATTER_TYPE = "#DEFAULT#";
	private static final String ATTR_SNIPPET = "snippet";
	private static final String ATTR_TYPE = "type";
	private static final String ATTR_NATURE = "nature";
	private static final String SCRIPT_DETAIL_FORMATTER_EXTENSION = DLTKDebugUIPlugin.PLUGIN_ID
			+ ".scriptDetailFormatter";

	private static HashMap managerInstances = new HashMap();
	private static final String CANNOT_EVALUATE = "Can't evaluate details.";
	private HashMap formatters = new HashMap();
	private DetailFormatter defaultFormatter = null;

	/**
	 * Return the default detail formatters manager.
	 * 
	 * @param natureId
	 * 
	 * @return default detail formatters manager.
	 */
	static public ScriptDetailFormattersManager getDefault(String natureId) {
		ScriptDetailFormattersManager instance = (ScriptDetailFormattersManager) managerInstances
				.get(natureId);
		if (instance == null) {
			instance = new ScriptDetailFormattersManager(natureId);
			managerInstances.put(natureId, instance);
		}
		return instance;
	}

	public ScriptDetailFormattersManager(String natureId) {
		populateDetailFormatters(natureId);
	}

	private void populateDetailFormatters(String natureId) {
		SimpleDLTKExtensionManager manager = new SimpleDLTKExtensionManager(
				SCRIPT_DETAIL_FORMATTER_EXTENSION);
		ElementInfo[] infos = manager.getElementInfos();
		for (int i = 0; i < infos.length; i++) {
			IConfigurationElement config = infos[i].getConfig();
			String nature = config.getAttribute(ATTR_NATURE);
			if (natureId.equals(nature)) {
				String code = config.getAttribute(ATTR_SNIPPET);
				String type = config.getAttribute(ATTR_TYPE);
				DetailFormatter formatter = new DetailFormatter(type, code,
						true);
				if (DEFAULT_FORMATTER_TYPE.equals(type)) {
					setDefaultFormatter(formatter);
				} else {
					addFormatter(formatter);
				}
			}
		}
	}

	private String getValueText(IValue value) {
		try {
			return value.getValueString();
		} catch (DebugException e) {
			return e.getMessage();
		}
	}

	public void computeValueDetail(final IScriptValue value,
			final IScriptThread thread, final IValueDetailListener listener) {
		Runnable postEventDispatch = new Runnable() {
			public void run() {
				DetailFormatter formatter = getDetailFormatter(value);
				if (thread == null || !thread.isSuspended()
						|| formatter == null || !formatter.isEnabled()) {
					listener.detailComputed(value, getValueText(value));
				} else {
					final IScriptEvaluationCommand command = value
							.createEvaluationCommand(formatter.getSnippet(),
									thread);

					command.asyncEvaluate(new IScriptEvaluationListener() {
						public void evaluationComplete(
								IScriptEvaluationResult result) {
							if (result == null)
								return;

							IScriptValue resultValue = result.getValue();
							if (resultValue != null) {
								listener.detailComputed(value,
										getValueText(resultValue));
							} else {
								listener.detailComputed(value, CANNOT_EVALUATE);
							}
						}
					});
				}
			}
		};
		DebugPlugin.getDefault().asyncExec(postEventDispatch);
	}

	protected DetailFormatter getDetailFormatter(IScriptValue value) {
		DetailFormatter formatter = (DetailFormatter) formatters.get(value
				.getType().getName());
		if (formatter == null)
			formatter = getDefaultFormatter();
		return formatter;
	}

	private DetailFormatter getDefaultFormatter() {
		return defaultFormatter;
	}

	public void setDefaultFormatter(DetailFormatter formatter) {
		defaultFormatter = formatter;
	}

	public void addFormatter(DetailFormatter formatter) {
		formatters.put(formatter.getTypeName(), formatter);
	}

	public void removeFormatter(DetailFormatter formatter) {
		formatters.remove(formatter.getTypeName());
	}
}