source: release-kits/lirk3/bin/ant-installer/src/org/tp23/antinstaller/runtime/IfPropertyHelper.java@ 14982

/* 
 * Copyright 2005 Paul Hinds
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.tp23.antinstaller.runtime;

import org.tp23.antinstaller.InstallException;
import org.tp23.antinstaller.InstallerContext;
import org.tp23.antinstaller.page.Page;
import org.tp23.antinstaller.page.SimpleInputPage;
import org.tp23.antinstaller.runtime.logic.Expression;
import org.tp23.antinstaller.runtime.logic.ExpressionBuilder;


/**
 * <p>Encapsulates code fo the ifProperty feature</p>
 * N.B.  It is the installer generator's responsibility to ensure that properties passed
 * to the less than or greater than test are valid Numbers.
 * The internal Java format used is a Double so avalid regex would be
 * something like [0-9]+\.*[0-9]*  or [0-9]+ for an Integer.
 * The rather strange -=  and += syntax is used because &gt; and &lt;
 * must be escaped to &amp;gt; and &amp;lt; in XML attributes and the legibility
 * of the configuration files would be impared.
 * REF: 1145496
 * @author Paul Hinds
 * @version $Id: IfPropertyHelper.java,v 1.5 2007/01/19 00:24:36 teknopaul Exp $
 */
public class IfPropertyHelper {
    
    private InstallerContext ctx = null;
    public IfPropertyHelper(InstallerContext ctx){
        this.ctx = ctx;
    }

    /**
     * @return boolean true to SHOW the page
     */
    public boolean ifProperty(Page next) throws InstallException {
        // show page if ifProperty is specified and property is correct
        if(next instanceof SimpleInputPage) {
            SimpleInputPage conditionalPage = (SimpleInputPage) next;
            String ifProperty = conditionalPage.getIfProperty();
            if (ifProperty != null) {
                Expression expression;
                try {
                    expression = ExpressionBuilder.parseLogicalExpressions( ctx.getInstaller().getResultContainer(),
                                                                                   ifProperty );
                }
                catch( ConfigurationException configExc ) {
                    throw new InstallException( "Error parsing ifProperty condition for page " + next.getName(),
                                                configExc );    
                }
                return expression.evaluate();
            }

        }
        return true; // show the page by default
    }
    
    /**
     * @return boolean true to SHOW the page
     */
    public boolean ifTarget(Page next, Page[] pages){
        // skip iftarget specified and target is missing
        if(next instanceof SimpleInputPage){
            SimpleInputPage conditionalPage = (SimpleInputPage) next;
            String ifTarget = conditionalPage.getIfTarget();
            if (ifTarget != null) {
                boolean show = false;
                for (int p = 0; p < pages.length; p++) {
                    show |= pages[p].isTarget(ifTarget);
                }
                return show;
            }
        }
        return true;
    }
}