com.izforge.izpack.installer.requirement.JavaVersionChecker Maven / Gradle / Ivy

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/*
 * IzPack - Copyright 2001-2012 Julien Ponge, All Rights Reserved.
 *
 * http://izpack.org/
 * http://izpack.codehaus.org/
 *
 * Copyright 2012 Tim Anderson
 *
 * 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 com.izforge.izpack.installer.requirement;

import com.izforge.izpack.api.data.InstallData;
import com.izforge.izpack.api.handler.Prompt;
import com.izforge.izpack.api.installer.RequirementChecker;
import com.izforge.izpack.api.rules.ComparisonOperator;
import com.izforge.izpack.core.rules.process.CompareVersionsMajorCondition;

/**
 * Verifies that the correct java version is available for installation to proceed.
 *
 * @author Tim Anderson
 */
public class JavaVersionChecker implements RequirementChecker
{

    /**
     * The installation data.
     */
    private final InstallData installData;

    /**
     * The prompt.
     */
    private final Prompt prompt;


    /**
     * Constructs a JavaVersionChecker.
     *
     * @param installData the installation data
     * @param prompt      the prompt
     */
    public JavaVersionChecker(InstallData installData, Prompt prompt)
    {
        this.installData = installData;
        this.prompt = prompt;
    }

    /**
     * Checks the Java version.
     *
     * @return true if requirements are met, otherwise false
     */
    @Override
    public boolean check()
    {
        String version = getJavaVersion();
        String required = installData.getInfo().getJavaVersion();
        if (required == null || version == null)
        {
            return true;
        }
        CompareVersionsMajorCondition comparator = new CompareVersionsMajorCondition();
        comparator.setInstallData(installData);
        comparator.setLeftOperand(version);
        comparator.setRightOperand(required);
        comparator.setOperator(ComparisonOperator.GREATEREQUAL);
        if (!comparator.isTrue())
        {
            versionNotAvailable(version, required);
            return false;
        }
        return true;
    }

    /**
     * Invoked when the required java version is not available.
     *
     * @param version         the current version
     * @param requiredVersion the required version
     */
    protected void versionNotAvailable(String version, String requiredVersion)
    {
        prompt.message(Prompt.Type.ERROR, getVersionNotAvailable(version, requiredVersion));
    }

    /**
     * Formats a message indicating the required java version isn't available.
     *
     * @param version         the current version
     * @param requiredVersion the required version
     * @return the formatted message
     */
    protected String getVersionNotAvailable(String version, String requiredVersion)
    {
        StringBuilder msg = new StringBuilder();
        msg.append("The application that you are trying to install requires a ");
        msg.append(requiredVersion);
        msg.append(" version or later of the Java platform.\n");
        msg.append("You are running a ");
        msg.append(version);
        msg.append(" version of the Java platform.\n");
        msg.append("Please upgrade to a newer version.");
        return msg.toString();
    }

    /**
     * Returns the java version.
     *
     * @return the java version, as determined by the java.version system property
     */
    protected String getJavaVersion()
    {
        return System.getProperty("java.version");
    }
}