SdkProjectMetadata.java

/*
 * Copyright 2010-2012 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.eclipse.sdk.ui;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.IPath;

/**
 * A metadata file containing the particular version of the AWS SDK for Java being
 * used by a particular project.
 */
public class SdkProjectMetadata {
    private static final String SDK_INSTALL_ROOT_PROPERTY = "sdkInstallRoot";

    private static final String SDK_PROPERTIES_FILE_NAME = "sdk.properties";

    final IProject project;

    public SdkProjectMetadata(IProject project) {
        this.project = project;
    }

    /**
     * Returns the root directory of the version of the SDK plugin being used by
     * the specified project.
     *
     * @return The root directory of the version of the SDK plugin being used by
     * the specified project.
     * @throws IOException if the plugin root directory could not be written to.
     */
    public File getSdkInstallRootForProject() throws IOException {
        Properties properties = loadProperties();
        String installRoot = properties.getProperty(SDK_INSTALL_ROOT_PROPERTY);

        if (installRoot == null) return null;

        return new File(installRoot);
    }

    /**
     * Writes the property file containing the root directory of the specified SDK
     * version.
     *
     * @param sdkInstallRoot The root directory of an SDK installation to be recorded.
     * @throws IOException if the plugin root directory could not be written to.
     */
    public void setSdkInstallRootForProject(File sdkInstallRoot) throws IOException {
        Properties properties = loadProperties();
        properties.setProperty(SDK_INSTALL_ROOT_PROPERTY, sdkInstallRoot.getAbsolutePath());
        saveProperties(properties);
    }

    /**
     * Empties the properties file to prepare for a version change.
     *
     * @throws IOException if the plugin root directory could not be written to.
     */
    public void clear()  throws IOException {
        Properties properties = new Properties();
        saveProperties(properties);
    }

    /*
     * Private Interface
     */

    private Properties loadProperties() throws IOException {
        IPath projectMetadataLocation = project.getWorkingLocation(JavaSdkPlugin.PLUGIN_ID);
        Properties properties = new Properties();
        IPath sdkProperties = projectMetadataLocation.append(SDK_PROPERTIES_FILE_NAME);

        if (sdkProperties.toFile().exists() == false) {
            return properties;
        }

        properties.load(new FileInputStream(sdkProperties.toFile()));
        return properties;
    }

    private void saveProperties(Properties properties) throws IOException {
        IPath projectMetadataLocation = project.getWorkingLocation(JavaSdkPlugin.PLUGIN_ID);
        IPath sdkProperties = projectMetadataLocation.append(SDK_PROPERTIES_FILE_NAME);
        properties.store(new FileOutputStream(sdkProperties.toFile()), null);
    }
}