/*******************************************************************************
* Copyright (c) 2006, 2015 Wind River Systems and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Wind River Systems - initial API and implementation
*******************************************************************************/
package org.eclipse.cdt.dsf.ui.viewmodel;
import org.eclipse.core.runtime.Platform;
/**
* Implementation of basic view model context interface.
* <p> The main purpose of the VMC wrapper is to re-direct adapter
* queries. The redirecting of adapter queries follows this order:
* <ol>
* <li>If context implements the adapter itself, it is returned.</li>
* <li>If the VM Adapter implements the adapter, the VM Adapter is returned.</li>
* <li>If the VM Provider implements the adapter, the VM Provider is returned.</li>
* <li>If the VM Node implements the adapter, the VM Node is returned.</li>
* </ol>
* </p>
* <p>
* Note: Deriving classes must override the Object.equals/hashCode methods.
* This is because the view model context objects are just wrappers that are
* created by the view model on demand, so the equals methods must use the
* object being wrapped to perform a meaningful comparison.
*
* @since 1.0
*/
abstract public class AbstractVMContext implements IVMContext {
protected final IVMNode fNode;
public AbstractVMContext(IVMNode node) {
fNode = node;
}
@Override
public IVMNode getVMNode() { return fNode; }
@SuppressWarnings("unchecked")
@Override
public <T> T getAdapter(Class<T> adapter) {
// If the context implements the given adapter directly, it always takes
// precedence.
if (adapter.isInstance(this)) {
return (T)this;
}
IVMProvider vmProvider = getVMNode().getVMProvider();
IVMAdapter vmAdapter = vmProvider.getVMAdapter();
if (adapter.isInstance(vmAdapter)) {
return (T)vmAdapter;
} else if (adapter.isInstance(vmProvider)) {
return (T)vmProvider;
} else if (adapter.isInstance(getVMNode())) {
return (T)getVMNode();
}
return Platform.getAdapterManager().getAdapter(this, adapter);
}
/** Deriving classes must override. */
@Override
abstract public boolean equals(Object obj);
/** Deriving classes must override. */
@Override
abstract public int hashCode();
}