bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/registry/MarkerQueryResult.java

/*******************************************************************************
 * Copyright (c) 2000, 2004 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.ui.internal.ide.registry;

/**
 * Instances of this class represent the result of a specific marker
 * query. Specifically they contain an ordered collection of marker 
 * attribute values.
 */

public class MarkerQueryResult {
    /**
     * An ordered collection of marker attribute values.
     */
    private String[] values;

    /**
     * Cached hash code value
     */
    private int hashCode;

    /**
     * Creates a new marker query result with the given values.
     * <p>
     * The values may not be empty.
     * </p>
     * 
     * @param markerAttributeValues the target marker's attribute values
     */
    public MarkerQueryResult(String[] markerAttributeValues) {
        if (markerAttributeValues == null) {
            throw new IllegalArgumentException();
        }
        values = markerAttributeValues;
        computeHashCode();
    }

    /* (non-Javadoc)
     * Method declared on Object.
     */
    public boolean equals(Object o) {
        if (!(o instanceof MarkerQueryResult))
            return false;

        if (o == this)
            return true;

        MarkerQueryResult mqr = (MarkerQueryResult) o;
        if (values.length != mqr.values.length)
            return false;

        for (int i = 0; i < values.length; i++) {
            if (!(values[i].equals(mqr.values[i])))
                return false;
        }

        return true;
    }

    /* (non-Javadoc)
     * Method declared on Object.
     */
    public int hashCode() {
        return hashCode;
    }

    /**
     * Computes the hash code for this instance.
     */
    public void computeHashCode() {
        hashCode = 19;

        for (int i = 0; i < values.length; i++) {
            hashCode = hashCode * 37 + values[i].hashCode();
        }
    }
}