CompositeDiff.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.diff;

import java.io.StringWriter;
import java.io.Writer;

import org.eclipse.persistence.tools.workbench.utility.io.IndentingPrintWriter;


/**
 * Allow a collection of diffs to be treated as a single diff.
 */
public class CompositeDiff implements Diff {
    /** the compared objects */
    private final Object object1;
    private final Object object2;

    /** the component diffs */
    private final Diff[] diffs;

    /** the differentiator the performed the comparison */
    private final Differentiator differentiator;


    public CompositeDiff(Object object1, Object object2, Diff[] diffs, Differentiator differentiator) {
        super();
        this.object1 = object1;
        this.object2 = object2;
        this.diffs = diffs;
        this.differentiator = differentiator;
    }

    /**
     * @see Diff#getObject1()
     */
    public Object getObject1() {
        return this.object1;
    }

    /**
     * @see Diff#getObject2()
     */
    public Object getObject2() {
        return this.object2;
    }

    /**
     * @see Diff#identical()
     */
    public boolean identical() {
        return ! this.different();
    }

    /**
     * @see Diff#different()
     */
    public boolean different() {
        // if any component diff is different, the entire diff is different
        for (int i = this.diffs.length; i-- > 0; ) {
            if (this.diffs[i].different()) {
                return true;
            }
        }
        return false;
    }

    /**
     * @see Diff#getDifferentiator()
     */
    public Differentiator getDifferentiator() {
        return this.differentiator;
    }

    /**
     * @see Diff#getDescription()
     */
    public String getDescription() {
        if (this.identical()) {
            return "";
        }
        Writer sw = new StringWriter();
        IndentingPrintWriter pw = new IndentingPrintWriter(sw, "    ");
        this.appendHeader(pw);
        pw.indent();
            this.appendDescription(pw);
        pw.undent();
        return sw.toString();
    }

    protected void appendHeader(IndentingPrintWriter pw) {
        pw.print("Objects are different:");
        pw.println();
        pw.print("object 1: ");
        pw.print(this.object1);
        pw.println();
        pw.print("object 2: ");
        pw.print(this.object2);
        pw.println();
    }

    /**
     * @see Diff#appendDescription(org.eclipse.persistence.tools.workbench.utility.io.IndentingPrintWriter)
     */
    public void appendDescription(IndentingPrintWriter pw) {
        // preserve the order of the component diffs
        int len = this.diffs.length;
        for (int i = 0; i < len; i++) {
            this.diffs[i].appendDescription(pw);
        }
    }

    /**
     * return the composite's component diffs
     */
    public Diff[] getDiffs() {
        return this.diffs;
    }

    /**
     * return the specified component diff
     */
    public Diff getDiff(int index) {
        return this.diffs[index];
    }

    /**
     * @see Object#toString()
     */
    public String toString() {
        return (this.identical()) ? NO_DIFFERENCE_DESCRIPTION : this.getDescription();
    }

}