src/main/java/freemarker/core/SwitchBlock.java

/*
 * Copyright (c) 2003 The Visigoth Software Society. All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Visigoth Software Society (http://www.visigoths.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
 *    project contributors may be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact visigoths@visigoths.org.
 *
 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
 *    nor may "FreeMarker" or "Visigoth" appear in their names
 *    without prior written permission of the Visigoth Software Society.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Visigoth Software Society. For more
 * information on the Visigoth Software Society, please see
 * http://www.visigoths.org/
 */

package freemarker.core;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;

import freemarker.template.TemplateException;

/**
 * An instruction representing a switch-case structure.
 */
final class SwitchBlock extends TemplateElement {

    private Case defaultCase;
    private final Expression searched;

    /**
     * @param searched the expression to be tested.
     */
    SwitchBlock(Expression searched) {
        this.searched = searched;
        nestedElements = new LinkedList();
    }

    /**
     * @param cas a Case element.
     */
    void addCase(Case cas) {
        if (cas.condition == null) {
            defaultCase = cas;
        }
        nestedElements.add(cas);
    }

    void accept(Environment env) 
        throws TemplateException, IOException 
    {
        boolean processedCase = false;
        Iterator iterator = nestedElements.iterator();
        try {
            while (iterator.hasNext()) {
                Case cas = (Case)iterator.next();
                boolean processCase = false;

                // Fall through if a previous case tested true.
                if (processedCase) {
                    processCase = true;
                } else if (cas.condition != null) {
                    // Otherwise, if this case isn't the default, test it.
                    processCase = EvalUtil.compare(
                            searched,
                            EvalUtil.CMP_OP_EQUALS, "case==", cas.condition, cas.condition, env);
                }
                if (processCase) {
                    env.visitByHiddingParent(cas);
                    processedCase = true;
                }
            }

            // If we didn't process any nestedElements, and we have a default,
            // process it.
            if (!processedCase && defaultCase != null) {
                env.visitByHiddingParent(defaultCase);
            }
        }
        catch (BreakInstruction.Break br) {}
    }

    protected String dump(boolean canonical) {
        StringBuffer buf = new StringBuffer();
        if (canonical) buf.append('<');
        buf.append(getNodeTypeSymbol());
        buf.append(' ');
        buf.append(searched.getCanonicalForm());
        if (canonical) {
            buf.append('>');
            for (int i = 0; i<nestedElements.size(); i++) {
                Case cas = (Case) nestedElements.get(i);
                buf.append(cas.getCanonicalForm());
            }
            buf.append("</").append(getNodeTypeSymbol()).append('>');
        }
        return buf.toString();
    }

    String getNodeTypeSymbol() {
        return "#switch";
    }

    int getParameterCount() {
        return 1;
    }

    Object getParameterValue(int idx) {
        if (idx != 0) throw new IndexOutOfBoundsException();
        return searched;
    }

    ParameterRole getParameterRole(int idx) {
        if (idx != 0) throw new IndexOutOfBoundsException();
        return ParameterRole.VALUE;
    }
    
}