bundles/org.eclipse.wst.sse.ui/src/org/eclipse/wst/sse/ui/internal/rules/PresentationCollector.java

/*******************************************************************************
 * Copyright (c) 2009, 2011 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.wst.sse.ui.internal.rules;

import java.util.AbstractCollection;
import java.util.Iterator;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.wst.sse.ui.internal.Logger;

/**
 * Passed to LineStyleProviders as the Collection for which StyleRanges are to
 * be added. This class provides additional sanity checks on the incoming
 * StyleRanges so that we do not rely upon SWT to report Errors with no record
 * of the StyleRange or contributing LineStyleProvider, as well as a slight
 * performance increase by not allocating a redundant collection for the
 * StyleRanges.
 * 
 * This class intentionally violates the contract for java.util.Collection.
 */

class PresentationCollector extends AbstractCollection {
	private final TextPresentation fPresentation;
	private int lastOffset;

	/**
	 * @param presentation
	 *            - the Presentation being added to
	 * @param applyOnAdd
	 */
	PresentationCollector(TextPresentation presentation) {
		super();
		Assert.isNotNull(presentation);
		fPresentation = presentation;
		lastOffset = 0;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.util.Collection#add(java.lang.Object)
	 */
	public boolean add(Object o) {
		StyleRange range = (StyleRange) o;
		if (lastOffset > range.start) {
			Logger.log(Logger.ERROR, "Overlapping start in StyleRange " + range.start + ":" + range.length); //$NON-NLS-1$ //$NON-NLS-2$
			return false;
		}
		else if (range.length < 0) {
			Logger.log(Logger.ERROR, "StyleRange with negative length" + range.start + ":" + range.length); //$NON-NLS-1$ //$NON-NLS-2$
			return false;
		}
		lastOffset = range.start + range.length;
		fPresentation.addStyleRange(range);
		return true;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.util.AbstractCollection#iterator()
	 */
	public Iterator iterator() {
		return fPresentation.getNonDefaultStyleRangeIterator();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.util.AbstractCollection#size()
	 */
	public int size() {
		throw new UnsupportedOperationException();
	}
}