plugins/org.eclipse.epp.installer.core/src/org/eclipse/epp/installer/core/ExtendableInstallConfiguration.java

package org.eclipse.epp.installer.core;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.epp.installer.core.model.IInstallStep;
import org.eclipse.epp.installer.core.model.IStepProcessor;
import org.eclipse.epp.installer.core.model.InstallStep;
import org.eclipse.epp.installer.core.model.Installer;
import org.eclipse.osgi.framework.internal.core.AbstractBundle;
import org.osgi.framework.Bundle;

public class ExtendableInstallConfiguration implements IConfigurationProvider {

	public static final String EXTENSION_POINT_NAME = 
		"org.eclipse.epp.installer.core.steps"; //$NON-NLS-1$

	private String id;
	
	public void configure(Installer installer) {
		final InstallOptions options = installer.getOptions();
		installer.setTitle(
			options.getString(InstallOptions.OPTION_PRODUCT_NAME) + " Installer"); //$NON-NLS-1$
		
		InstallStepFactory factory = InstallStepFactory.getInstance();

		IExtensionRegistry registry = org.eclipse.core.runtime.Platform.getExtensionRegistry();
		IExtensionPoint extensionPoint = registry.getExtensionPoint(EXTENSION_POINT_NAME);
		IExtension[] extensions = extensionPoint.getExtensions();
		for (int a = 0; a < extensions.length; a++) {
			IExtension extension = extensions[a];
			AbstractBundle bundle = (AbstractBundle) org.eclipse.core.runtime.Platform.getBundle(
					extension.getContributor().getName());
			IConfigurationElement[] elements = extension.getConfigurationElements();
			for (int i = 0; i < elements.length; i++) {
				if ("steps".equals(elements[i].getName()) && 
						getId() != null && getId().equals(elements[i].getAttribute("providerId"))) {
					IConfigurationElement[] steps = elements[i].getChildren();
					for (int b=0; b < steps.length; b++) {
						IConfigurationElement element = steps[b];
						String entryName = element.getName();
						if ("step".equals(entryName)) { //$NON-NLS-1$
							String id = element.getAttribute("id"); //$NON-NLS-1$
							IInstallStep step = factory.createStep(id, installer);
							if (step != null) {
								String title = element.getAttribute("title"); //$NON-NLS-1$
								String description = resolveNewLineCharacters(element.getAttribute("description")); //$NON-NLS-1$
								if (step instanceof InstallStep) {
									((InstallStep) step).setTitle(title);
									((InstallStep) step).setDescription(description);
								}
								IConfigurationElement[] childs = element.getChildren();
								for (int j = 0; j < childs.length; j++) {
									String childName = childs[j].getName();
									if ("parameter".equals(childName)) { //$NON-NLS-1$
										String key = childs[j].getAttribute("key"); //$NON-NLS-1$
										String value = resolveNewLineCharacters(childs[j].getAttribute("value")); //$NON-NLS-1$
										step.setProperty(key, value);
									}
									else if ("process".equals(childName)) { //$NON-NLS-1$
										getStepProcessor(childs[j].getAttribute("class"), bundle).process(step); //$NON-NLS-1$
									}
									else if ("aboutToStep".equals(childName)) { //$NON-NLS-1$
										if (step instanceof InstallStep) {
											IConfigurationElement[] aboutToStepChilds = childs[j].getChildren();
											for (int k = 0; k < aboutToStepChilds.length; k++) {
												String aboutToStepChildName = aboutToStepChilds[k].getName();
												if ("parameter".equals(aboutToStepChildName)) { //$NON-NLS-1$
													String key = aboutToStepChilds[k].getAttribute("key"); //$NON-NLS-1$
													String value = resolveNewLineCharacters(aboutToStepChilds[k].getAttribute("value")); //$NON-NLS-1$
													((InstallStep) step).aboutToStepSetProperty(key, value);
												}
												else if ("process".equals(aboutToStepChildName)) { //$NON-NLS-1$
													IStepProcessor processor = getStepProcessor(aboutToStepChilds[k].getAttribute("class"), bundle); //$NON-NLS-1$
													((InstallStep) step).aboutToStepAddProcessor(processor);
												}
											}
										}
									}
								}
								installer.add(step);
							}
							else {
								//TODO: log error
								System.out.println("Unable to create install step \"" + id + "\"");
							}
						} 
					}
				}				
			}
		}
	}

	private String resolveNewLineCharacters(String s) {
		if (s == null) {
			return null;
		}

		StringBuffer resultString = new StringBuffer();
		int begin = 0;
		while (true) {
			int end = s.indexOf("\\n", begin);
			if (end != -1) {
				resultString.append(s.substring(begin, end));
				resultString.append("\n");
				begin = end + 2;
			}
			else {
				resultString.append(s.substring(begin));
				break;
			}
		}
				
		return resultString.toString();
	}
	
	private IStepProcessor getStepProcessor(String className, Bundle bundle) {
		try {
			Class processClass = bundle.loadClass(className);
			IStepProcessor processor = (IStepProcessor) processClass.newInstance();
			return processor;
		} catch (Throwable e) {
			throw new RuntimeException(e);
		}
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getId() {
		return id;
	}
	
}