Eclipse插件开发小结

要了解swt，jface的一些机制，不过大部分都可以查阅资料清楚具体的用法。

这次代码生成插件的开发首先遇到的难点是模块的构建次序，按照jsmart的工作流程，数据库加载，实体构建，包名设定，框架选择。各模块之间的关联处理比较麻烦，主要是一些参数的传递。第一步将框架搭建起来。

第二个难点是plugin.xml的配置，其中runtime的配置没写，也就是插件运行环境的jar包没有加载，是的插件运行时总是报错，这个错误调了很久，破费周折。发现这一类的问题插件本身不会报错，但是会转向event事件的处理，感觉这种错误太隐蔽了。

第三个难点是rcp的路径选择问题。很麻烦，从这个才知道了Eclipse中有一个jdt包，包含了Eclipse工程的很多信息，感觉相当实用。路径的一些现实代码如下：

package testplugin.actions;

import java.net.URL;

import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.IWorkbenchWindowActionDelegate;
import org.eclipse.ui.internal.UIPlugin;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.adaptor.LocationManager;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.osgi.service.datalocation.Location;
import org.osgi.framework.Bundle;

import testplugin.Activator;

/**
 * Our sample action implements workbench action delegate. The action proxy will
 * be created by the workbench and shown in the UI. When the user tries to use
 * the action, this delegate will be created and execution will be delegated to
 * it.
 * 
 * @see IWorkbenchWindowActionDelegate
 */
public class SampleAction implements IWorkbenchWindowActionDelegate {
    private IWorkbenchWindow window;
    private static IProject project = null;

    /**
     * The constructor.
     */
    public SampleAction() {
    }

    /**
     * The action has been activated. The argument of the method represents the
     * 'real' action sitting in the workbench UI.
     * 
     * @see IWorkbenchWindowActionDelegate#run
     */
    public void run(IAction action) {
        Location installLoc = LocationManager.getInstallLocation();
        String path = null;
        String installPath = null;
        if (installLoc != null) {

            URL installURL = installLoc.getURL();
            // assume install URL is file: based
            path = installURL.getPath();
        }

        installPath = path.substring(1, path.length());

        Bundle bundle = Platform.getBundle("webGenerator");
        String bundleLocation = bundle.getLocation();

        String resource = SampleAction.class.getResource("generator.properties").toString();

        String msg;
        msg = "plugin abstract path:" + Activator.getDefault().getStateLocation().makeAbsolute().toFile().getAbsolutePath();
        msg += "\nworkspace:" + Platform.getInstanceLocation().getURL().getPath();
        msg += "\ninstallPath:" + installPath;
        msg += "\n" + UIPlugin.getDefault().getBundle().getHeaders().get("Bundle-Name");
        msg += "\n" + bundleLocation;
        msg += "\n" + resource;

        MessageDialog.openInformation(window.getShell(), "TestPlugin", msg);

    }

    /**
     * Selection in the workbench has been changed. We can change the state of
     * the 'real' action here if we want, but this can only happen after the
     * delegate has been created.
     * 
     * @see IWorkbenchWindowActionDelegate#selectionChanged
     */
    public void selectionChanged(IAction action, ISelection selection) {
        // Test project resource selection
        if (selection instanceof IStructuredSelection) {
            String msg;
            IStructuredSelection structuredSelect = (IStructuredSelection) selection;
            if (!structuredSelect.isEmpty()) {
                Object obj = structuredSelect.getFirstElement();
                if (obj instanceof IProject) {
                    project = ((IProject) obj).getProject();
                    msg = "getProjectName:" + getProjectName();
                    msg += "getWorkplaceName:" + getWorkplaceName();
                    msg += "getProjectPath:" + getProjectPath();
                    msg += "getPath:" + getPath();
                    msg += "getPluginPath:" + getPluginPath();
                    MessageDialog.openInformation(window.getShell(), "TestPlugin", msg);
                    return;
                } else {
                    System.out.println("The selection is not a project");
                }
            }
        }
    }

    /**
     * We can use this method to dispose of any system resources we previously
     * allocated.
     * 
     * @see IWorkbenchWindowActionDelegate#dispose
     */
    public void dispose() {
    }

    /**
     * We will cache window object in order to be able to provide parent shell
     * for the message dialog.
     * 
     * @see IWorkbenchWindowActionDelegate#init
     */
    public void init(IWorkbenchWindow window) {
        this.window = window;
    }

    /**
     * 得到项目名称
     * 
     * @return
     */
    public static String getProjectName() {
        return project.getName();
    }

    /**
     * 得到workplace的运行文件
     * 
     * @return
     */
    public static String getWorkplaceName() {
        String path = Platform.getInstanceLocation().getURL().getPath();
        return path.substring(1, path.length());
    }

    /**
     * 得到project项目的文件路径
     * 
     * @return
     */
    public static String getProjectPath() {
        return project.getProject().getLocation().toString() + "/";
    }

    /**
     * 得到Eclipse运行目录
     * 
     * @return
     */
    @SuppressWarnings("restriction")
    public static String getPath() {
        Location installLoc = LocationManager.getInstallLocation();
        String path = null;
        String installPath = null;
        if (installLoc != null) {

            URL installURL = installLoc.getURL();
            // assume install URL is file: based
            path = installURL.getPath();
        }
        installPath = path.substring(1, path.length());
        return installPath;
    }

    /**
     * 得到plugin所在的位置，文件夹为.../filename/;jar包为.../filename.jar
     * 
     * @return
     */
    public static String getPluginPath() {
        Bundle bundle = Platform.getBundle("webGenerator");
        String bundleLocation = bundle.getLocation();
        String[] items = bundleLocation.split(":");
        String pluginLocation = getPath() + items[items.length - 1];
        return pluginLocation;
    }

}

这次项目对插件的认识姑且就是这些，虽然相当肤浅，不过也算是了解的，感觉Eclipse的却比较强大，java也很强大。感觉像在编程上有所成就真是任重而道远啊。

什么时候要吧Eclipse的框架理一下啊！