# AbstractGroupVisitor.java

    /*******************************************************************************
     * Copyright (c) 2009, 2013 Mountainminds GmbH & Co. KG and Contributors
     * 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:
     *    Marc R. Hoffmann - initial API and implementation
     *
     *******************************************************************************/
    package org.jacoco.report.internal;

    import java.io.IOException;

    import org.jacoco.core.analysis.CoverageNodeImpl;
    import org.jacoco.core.analysis.IBundleCoverage;
    import org.jacoco.core.analysis.ICoverageNode.ElementType;
    import org.jacoco.report.IReportGroupVisitor;
    import org.jacoco.report.ISourceFileLocator;

    /**
     * Internal base visitor to calculate group counter summaries for hierarchical
     * reports.
     */
    public abstract class AbstractGroupVisitor implements IReportGroupVisitor {

    	/** coverage node for this group to total counters */
    	protected final CoverageNodeImpl total;

    	private AbstractGroupVisitor lastChild;

    	/**
    	 * Creates a new group with the given name.
    	 *
    	 * @param name
    	 *            name for the coverage node created internally
    	 */
    	protected AbstractGroupVisitor(final String name) {
    		total = new CoverageNodeImpl(ElementType.GROUP, name);
    	}

    	public final void visitBundle(final IBundleCoverage bundle,
    			final ISourceFileLocator locator) throws IOException {
    		finalizeLastChild();
    		total.increment(bundle);
    		handleBundle(bundle, locator);
    	}

    	/**
    	 * Called to handle the given bundle in a specific way.
    	 *
    	 * @param bundle
    	 *            analyzed bundle
    	 * @param locator
    	 *            source locator
    	 * @throws IOException
    	 *             if the report can't be written
    	 */
    	protected abstract void handleBundle(IBundleCoverage bundle,
    			ISourceFileLocator locator) throws IOException;

    	public final IReportGroupVisitor visitGroup(final String name)
    			throws IOException {
    		finalizeLastChild();
    		lastChild = handleGroup(name);
    		return lastChild;
    	}

    	/**
    	 * Called to handle a group with the given name in a specific way.
    	 *
    	 * @param name
    	 *            name of the group
    	 * @return created child group
    	 * @throws IOException
    	 *             if the report can't be written
    	 */
    	protected abstract AbstractGroupVisitor handleGroup(final String name)
    			throws IOException;

    	/**
    	 * Must be called at the end of every group.
    	 *
    	 * @throws IOException
    	 *             if the report can't be written
    	 */
    	public final void visitEnd() throws IOException {
    		finalizeLastChild();
    		handleEnd();
    	}

    	/**
    	 * Called to handle the end of this group in a specific way.
    	 *
    	 * @throws IOException
    	 *             if the report can't be written
    	 */
    	protected abstract void handleEnd() throws IOException;

    	private void finalizeLastChild() throws IOException {
    		if (lastChild != null) {
    			lastChild.visitEnd();
    			total.increment(lastChild.total);
    			lastChild = null;
    		}
    	}

    }