bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/internal/p2/metadata/RequirementChange.java

/*******************************************************************************
 *  Copyright (c) 2007, 2009 IBM Corporation 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:
 *      IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.equinox.internal.p2.metadata;

import org.eclipse.equinox.internal.provisional.p2.core.Version;
import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
import org.eclipse.equinox.internal.provisional.p2.metadata.IRequiredCapability;
import org.eclipse.equinox.internal.provisional.p2.metadata.IRequirementChange;

public class RequirementChange implements IRequirementChange {
	private IRequiredCapability applyOn;
	private IRequiredCapability newValue;

	public RequirementChange(IRequiredCapability applyOn2, IRequiredCapability newValue2) {
		if (applyOn2 == null && newValue2 == null)
			throw new IllegalArgumentException();
		this.applyOn = applyOn2;
		this.newValue = newValue2;
	}

	public IRequiredCapability applyOn() {
		return applyOn;
	}

	public IRequiredCapability newValue() {
		return newValue;
	}

	public boolean matches(IRequiredCapability toMatch) {
		if (!toMatch.getNamespace().equals(applyOn.getNamespace()))
			return false;
		if (!toMatch.getName().equals(applyOn.getName()))
			return false;
		if (toMatch.getRange().equals(applyOn.getRange()))
			return true;

		return intersect(toMatch.getRange(), applyOn.getRange()) == null ? false : true;
	}

	private VersionRange intersect(VersionRange r1, VersionRange r2) {
		Version resultMin = null;
		boolean resultMinIncluded = false;
		Version resultMax = null;
		boolean resultMaxIncluded = false;

		int minCompare = r1.getMinimum().compareTo(r2.getMinimum());
		if (minCompare < 0) {
			resultMin = r2.getMinimum();
			resultMinIncluded = r2.getIncludeMinimum();
		} else if (minCompare > 0) {
			resultMin = r1.getMinimum();
			resultMinIncluded = r1.getIncludeMinimum();
		} else if (minCompare == 0) {
			resultMin = r1.getMinimum();
			resultMinIncluded = r1.getIncludeMinimum() && r2.getIncludeMinimum();
		}

		int maxCompare = r1.getMaximum().compareTo(r2.getMaximum());
		if (maxCompare > 0) {
			resultMax = r2.getMaximum();
			resultMaxIncluded = r2.getIncludeMaximum();
		} else if (maxCompare < 0) {
			resultMax = r1.getMaximum();
			resultMaxIncluded = r1.getIncludeMaximum();
		} else if (maxCompare == 0) {
			resultMax = r1.getMaximum();
			resultMaxIncluded = r1.getIncludeMaximum() && r2.getIncludeMaximum();
		}

		int resultRangeComparison = resultMin.compareTo(resultMax);
		if (resultRangeComparison < 0)
			return new VersionRange(resultMin, resultMinIncluded, resultMax, resultMaxIncluded);
		else if (resultRangeComparison == 0 && resultMinIncluded == resultMaxIncluded)
			return new VersionRange(resultMin, resultMinIncluded, resultMax, resultMaxIncluded);
		else
			return null;
	}

	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((applyOn == null) ? 0 : applyOn.hashCode());
		result = prime * result + ((newValue == null) ? 0 : newValue.hashCode());
		return result;
	}

	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (!(obj instanceof IRequirementChange))
			return false;
		final IRequirementChange other = (IRequirementChange) obj;
		if (applyOn == null) {
			if (other.applyOn() != null)
				return false;
		} else if (!applyOn.equals(other.applyOn()))
			return false;
		if (newValue == null) {
			if (other.newValue() != null)
				return false;
		} else if (!newValue.equals(other.newValue()))
			return false;
		return true;
	}

	public String toString() {
		return applyOn + " --> " + newValue; //$NON-NLS-1$
	}
}