AbstractExtension.java

/**
* OLAT - Online Learning and Training<br>
* http://www.olat.org
* <p>
* Licensed under the Apache License, Version 2.0 (the "License"); <br>
* you may not use this file except in compliance with the License.<br>
* You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing,<br>
* software distributed under the License is distributed on an "AS IS" BASIS, <br>
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
* See the License for the specific language governing permissions and <br>
* limitations under the License.
* <p>
* Copyright (c) since 2004 at Multimedia- & E-Learning Services (MELS),<br>
* University of Zurich, Switzerland.
* <hr>
* <a href="http://www.openolat.org">
* OpenOLAT - Online Learning and Training</a><br>
* This file has been modified by the OpenOLAT community. Changes are licensed
* under the Apache 2.0 license as the original file.  
* <p>
*/ 

package org.olat.core.extensions;

import org.olat.core.configuration.AbstractConfigOnOff;
import org.olat.core.extensions.action.ActionExtensionSecurityCallback;
import org.olat.core.gui.UserRequest;
import org.olat.core.logging.AssertException;

/**
 * @author Christian Guretzki
 */
abstract public class AbstractExtension extends AbstractConfigOnOff implements Extension {

	private int order = 0;
	private String secCallbackName = null;
	private String nodeIdentifierIfParent;
	private String parentTreeNodeIdentifier;
	
	public int getOrder() {
		return order;
	}
	
	// used by Spring
	public void setOrder(int order){
		this.order = order;
	}
	
	@Override
	public int compareTo(Extension o) {
		if(getOrder() < o.getOrder()) return -1;
		if(getOrder() > o.getOrder()) return 1;
		return 0;
	}
	
	/**
	 * @overrides
	 * @see org.olat.core.extensions.Extension#getUniqueExtensionID()
	 */
	public String getUniqueExtensionID(){
		StringBuilder sb = new StringBuilder();
		sb.append(this.getClass().getName()).append(":").append(order).append(":");
		return sb.toString();
	}
	
	/**
	 * [ Spring ]
	 * define the name of a class implementing ActionExtensionSecurityCallback.
	 * this gets asked later on to validate a UserRequest
	 */
	public void setSecurityCallbackClassName(String secCallbackName){
		this.secCallbackName = secCallbackName;
	}
	
	/**
	 * returns the defined securityCallback, if none was defined a default SecurityCallback is returned
	 */
	public ActionExtensionSecurityCallback getActionExtensionSecurityCallback() {
		ActionExtensionSecurityCallback securityCallback = null;
		if (secCallbackName != null) {
			// try to lazy instantiate the callback Object
			Class<?> cclazz;
			Exception re = null;
			try {
				cclazz = Thread.currentThread().getContextClassLoader().loadClass(secCallbackName);
				Object o = cclazz.newInstance();
				securityCallback = (ActionExtensionSecurityCallback) o;
			} catch (ClassNotFoundException e) {
				re = e;
			} catch (SecurityException e) {
				re = e;
			} catch (IllegalArgumentException e) {
				re = e;
			} catch (InstantiationException e) {
				re = e;
			} catch (IllegalAccessException e) {
				re = e;
			} finally {
				if (re != null) { throw new AssertException("Could not create ActionExtensionSecurityCallback via reflection. classname: "
						+ secCallbackName, re); }
			}
		} else {
			// load a default callback
			ActionExtensionSecurityCallback aescDefault = new ActionExtensionSecurityCallback() {
				@Override
				public boolean isAllowedToLaunchActionController(UserRequest ureq) {
					return true;
				}
			};
			securityCallback = aescDefault;
		}
		return securityCallback;
	}


	/**
	 * @return Returns the nodeIdentifierIfParent.
	 * if this is a parent node it should have a nodeIdentifierIfParent
	 */
	public String getNodeIdentifierIfParent() {
		return nodeIdentifierIfParent;
	}

	/**
	 * [ Spring ]
	 * @param nodeIdentifierIfParent The nodeIdentifierIfParent to set.
	 * if this is a parent node it should have a nodeIdentifierIfParent
	 */
	public void setNodeIdentifierIfParent(String nodeIdentifierIfParent) {
		this.nodeIdentifierIfParent = nodeIdentifierIfParent;
	}

	/**
	 * @return Returns the parentTreeNodeIdentifier.
	 * get the corresponding parentNodeIdentifier, this actionExtension will get attached to
	 */
	public String getParentTreeNodeIdentifier() {
		return parentTreeNodeIdentifier;
	}

	/**
	 * [ Spring ]
	 * @param parentTreeNodeIdentifier The parentTreeNodeIdentifier to set.
	 * set the corresponding parentNodeIdentifier, this actionExtension will get attached to
	 */
	public void setParentTreeNodeIdentifier(String parentTreeNodeIdentifier) {
		this.parentTreeNodeIdentifier = parentTreeNodeIdentifier;
	}

	/**
	 * if there is a security-callback provided, go and check access for user
	 * @see org.olat.core.extensions.Extension#getExtensionFor(java.lang.String, org.olat.core.gui.UserRequest)
	 */
	@Override
	public ExtensionElement getExtensionFor(String extensionPoint, UserRequest ureq) {
		ExtensionElement extEl = getExtensionFor(extensionPoint);
		if (extEl != null && isSecCallbackNameSet()) {
			// no session on dmz!
			boolean isDMZ = ureq.getUserSession() == null || ureq.getUserSession().getIdentityEnvironment().getRoles() == null;
			if (isDMZ || !getActionExtensionSecurityCallback().isAllowedToLaunchActionController(ureq)) {
				return null;
			}
		}
		return extEl;
	}
	
	protected abstract ExtensionElement getExtensionFor(String extensionPoint);
	
	
	public boolean isSecCallbackNameSet(){
		return secCallbackName != null;
	}
	
}