tests/org.eclipse.ui.tests.performance/src/org/eclipse/ui/tests/performance/ContentDescriberForTestsOnly.java

/*******************************************************************************
 * Copyright (c) 2005 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.tests.performance;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;

import org.eclipse.core.runtime.QualifiedName;
import org.eclipse.core.runtime.content.IContentDescriber;
import org.eclipse.core.runtime.content.IContentDescription;
import org.eclipse.core.runtime.content.ITextContentDescriber;

/**
 * This test ContentDescriber added specifically for OpenNavigatorFolderTest.
 * 
 */

public final class ContentDescriberForTestsOnly implements ITextContentDescriber {

	/*
	 * this "simulated time" represents how long a content describer might
	 * take parsing a file. Offhand (i.e. just guessing) 2000 msecs would be "bad case" examples. 
	 * 20 msecs would be near a good, optimistic case.
	 * I've picked 75 msecs for this test, to represent "normal" case 
	 * (such as the HTML parser that gave rise to the original bug :)  
	 * 
	 * Note: unlike a "real" ContentDescriber, this one only effects "elapsed
	 * time", not "CPU Time", since all it is doing is sleeping.
	 */
	private static final int SIMULATED_CALCULATION_TIME = 75;
	private static final QualifiedName[] SUPPORTED_OPTIONS = {IContentDescription.CHARSET, IContentDescription.BYTE_ORDER_MARK};

	public int describe(InputStream contents, IContentDescription description) throws IOException {
		int result = IContentDescriber.INDETERMINATE;

		if (description == null) {
			result = computeValidity(contents);
		}
		else {
			calculateSupportedOptions(contents, description);
			// assummming we should return same 'validity' value we did
			// when called before. (technically, could be a performance issue
			// in future, so might want to check if any 'ol value would
			// be ok here.
			result = computeValidity(contents);
		}

		return result;
	}

	public int describe(Reader contents, IContentDescription description) throws IOException {
		int result = IContentDescriber.INDETERMINATE;

		if (description == null) {
			result = computeValidity(contents);
		}
		else {
			calculateSupportedOptions(contents, description);
			// assummming we should return same 'validity' value we did
			// when called before. (technically, could be a performance issue
			// in future, so might want to check if hard coded 'valid' would
			// be ok here.
			result = computeValidity(contents);
		}

		return result;
	}

	public QualifiedName[] getSupportedOptions() {

		return SUPPORTED_OPTIONS;
	}

	private void calculateSupportedOptions(InputStream contents, IContentDescription description) throws IOException {
		if (isRelevent(description)) {
			makeBusy();
		}
	}

	private void makeBusy() {
		// for this test "content type", we don't
		// really calculate anything. We just
		// just take a long time doing nothing.
		try {
			Thread.sleep(SIMULATED_CALCULATION_TIME);
		}
		catch (InterruptedException e) {
			// never expected
			e.printStackTrace();
		}
	}

	/**
	 * @param contents
	 * @param description
	 * @throws IOException
	 */
	private void calculateSupportedOptions(Reader contents, IContentDescription description) throws IOException {
		if (isRelevent(description)) {
			makeBusy();
		}
	}

	private int computeValidity(InputStream inputStream) {
		// currently no contents specific check for valid HTML contents
		// (this may change once we add XHTML content type)
		return IContentDescriber.INDETERMINATE;
	}

	private int computeValidity(Reader reader) {
		// no contents specific check for valid HTML contents
		// (this may change once we add XHTML content type)
		return IContentDescriber.INDETERMINATE;
	}

	/**
	 * @param description
	 * @return
	 */
	private boolean isRelevent(IContentDescription description) {
		boolean result = false;
		if (description == null)
			result = false;
		else if (description.isRequested(IContentDescription.BYTE_ORDER_MARK))
			result = true;
		else if (description.isRequested(IContentDescription.CHARSET))
			result = true;
		return result;
	}

}