com.cb.eclipse.folding.java.calculation.StrategyFactory.java Source code

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Here is the source code for com.cb.eclipse.folding.java.calculation.StrategyFactory.java

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/*******************************************************************************
 * Copyright (c) 2004 Coffee-Bytes.com and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.opensource.org/licenses/cpl.php
 * 
 * Contributors:
 *     Coffee-Bytes.com - initial API and implementation
 *******************************************************************************/
package com.cb.eclipse.folding.java.calculation;

import org.eclipse.jdt.core.IJavaElement;

// TODO - Make as many strategies as possible stateless.

/**
 * The StrategyFactory as defined here maps an IJavaElement to a
 * CalculationStrategy. This allows the projection calculator to focus on the
 * algorithm of processing a tree of IJavaElement instances exclusively.
 * 
 * @author R.J. Lorimer
 */
public class StrategyFactory {

    // NO-OP singleton.
    private static RegionCalculationStrategy NO_OP_STRATEGY = new NoOpStrategy();

    /**
     * Get a CalculationStrategy instance that is capable of handling the region
     * building for <code>elem</code>
     * 
     * @param elem
     *            The java element to find a calculation strategy for.
     * @return The Calculation strategy meant for processing elem.
     */
    public static RegionCalculationStrategy instance(JavaProjectionCalculator calculator, IJavaElement elem) {
        int type = elem.getElementType();
        switch (type) {
        case IJavaElement.TYPE:
            return new CommentPrefixStrategy(new TypeStrategy());
        case IJavaElement.FIELD:
        case IJavaElement.METHOD:
            return new CommentPrefixStrategy(new MethodStrategy());
        case IJavaElement.IMPORT_CONTAINER:
            return new ImportContainerStrategy();
        case IJavaElement.COMPILATION_UNIT:
        case IJavaElement.CLASS_FILE:
            return new UserDefinedStrategy(new RootStrategy());
        case IJavaElement.INITIALIZER:
            return new CommentPrefixStrategy(new StaticInitializerStrategy());
        default:
            return NO_OP_STRATEGY;
        }
    }

}