framework/bundles/org.eclipse.ecf.identity/src/org/eclipse/ecf/core/identity/BaseID.java

/*******************************************************************************
 * Copyright (c) 2004 Composent, Inc. 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: Composent, Inc. - initial API and implementation
 ******************************************************************************/
package org.eclipse.ecf.core.identity;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IAdapterManager;
import org.eclipse.ecf.internal.core.identity.Activator;

/**
 * Base class for ID implementation classes
 * 
 * Extensions for the <b>org.eclipse.ecf.namespace</b> extension point that
 * expose new Namespace subclasses and their own ID implementations are
 * recommended (but not required) to use this class as a superclass.
 * 
 */
public abstract class BaseID implements ID {

	private static final long serialVersionUID = -6242599410460002514L;

	protected Namespace namespace;

	protected BaseID() {
		// 
	}

	protected BaseID(Namespace namespace) {
		Assert.isNotNull(namespace, "namespace cannot be null"); //$NON-NLS-1$
		this.namespace = namespace;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Comparable#compareTo(T)
	 */
	public int compareTo(Object o) {
		Assert.isTrue(o != null && o instanceof BaseID, "incompatible types for compare"); //$NON-NLS-1$
		return namespace.getCompareToForObject(this, (BaseID) o);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	public boolean equals(Object o) {
		if (o == null)
			return false;
		if (!(o instanceof BaseID)) {
			return false;
		}
		return namespace.testIDEquals(this, (BaseID) o);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ecf.core.identity.ID#getName()
	 */
	public String getName() {
		return namespace.getNameForID(this);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ecf.core.identity.ID#getNamespace()
	 */
	public Namespace getNamespace() {
		return namespace;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode() {
		return namespace.getHashCodeForID(this);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ecf.core.identity.ID#toExternalForm()
	 */
	public String toExternalForm() {
		return namespace.toExternalForm(this);
	}

	/**
	 * Called by {@link Namespace#getCompareToForObject(BaseID, BaseID)}.
	 * 
	 * @param o the other ID to compare to.  Will not be <code>null</code>.
	 * @return the appropriate value as per {@link Comparable} contract.
	 */
	protected abstract int namespaceCompareTo(BaseID o);

	/**
	 * Called by {@link Namespace#testIDEquals(BaseID, BaseID)}.
	 * @param o the other ID to test against.  May be <code>null</code>.
	 * @return <code>true</code> if this ID is equal to the given ID.  <code>false</code> otherwise.
	 */
	protected abstract boolean namespaceEquals(BaseID o);

	/**
	 * Called by {@link Namespace#getNameForID(BaseID)}.
	 * 
	 * @return String name for this ID.  Must not be <code>null</code>.  Value returned should be unique within this Namespace.
	 */
	protected abstract String namespaceGetName();

	/**
	 * Called by {@link Namespace#getHashCodeForID(BaseID)}.
	 * 
	 * @return int hashCode for this ID.  Returned value must be unique within this process.
	 */
	protected abstract int namespaceHashCode();

	/**
	 * Called by {@link Namespace#toExternalForm(BaseID)}. 
	 * 
	 * @return String that represents this ID.  Default implementation is to return
	 * <pre>
	 * namespace.getScheme() + Namespace.SCHEME_SEPARATOR + namespaceGetName();
	 * </pre>
	 */
	protected String namespaceToExternalForm() {
		return namespace.getScheme() + Namespace.SCHEME_SEPARATOR + namespaceGetName();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.runtime.IAdaptable#getAdapter(java.lang.Class)
	 */
	public Object getAdapter(Class clazz) {
		IAdapterManager adapterManager = Activator.getDefault().getAdapterManager();
		if (adapterManager == null)
			return null;
		return adapterManager.loadAdapter(this, clazz.getName());
	}
}