gvSIG projects pool

package org.gvsig.jvmpreferences.nativeprefs;

import java.io.File;

/**

 * This class abstracts the complexity of reading/storing

 * memory preferences for different operating systems.

 * It has methods to

 * read and write the configured maximum memory for gvSIG, and it provides

 * other convenience methods related with memory management.

 * 

 * Note that the configuration managed by this interface is system-dependent

 * (different configuration files are used on each operating system), so

 * different implementations are provided for each system.

 * 

 * @author Cesar Martinez Izquierdo

 *

 */

public interface MemoryPreferences {

        /**

         * Gets the absolute path to the memory configuration file

         * 

         * @return

         */

        public File getConfigFile();

        /**

         * Checks whether the current Java process has write permission on the

         * memory configuration file. As, gvSIG can be installed on a folder

         * having restricted permissions, the file may not be writable unless

         * gvSIG is executed as administrator. This is usually the case in

         * Windows Vista, 7 and 8.

         * 

         * @return Returns <code>true</code> if the configuration file is writable by this process,

         * <code>false</code> otherwise.

         */

        public boolean isConfigWritable();

        /**

         * Returns the total amount of RAM memory installed on this computer.

         * 

         * @return The total amount of memory, measured in megabytes

         */

        public int getTotalSystemMemory();

        /**

         * Gets the maximum amount of memory (in megabytes) that

         * it is considered to be safe for this computer.

         * 

         * This amount is calculated based on

         * different parameters such as the total amount of available

         * RAM memory on the computer and the architecture of the

         * JVM (32 bits or 64 bits).

         * 

         * Due to the way in which the Java Virtual Machine, it is

         * unsafe to use more than ~1200 MB for 32 bit JVMs, as the

         * JVM needs a contiguous memory space and it will not start

         * at all if it is not available. Note that the availability

         * of a free, contiguous memory space also depends on the

         * previously loaded programs, so an unsafe value may work

         * on one JVM execution and fail on a different one.

         *

         * @return

         */

        public int getSafeMemoryMaximum();

        /**

         * Reads the maximum configured memory (-Xmx) from gvSIG

         * launch configuration file

         * 

         * @return The maximum configured memory, measured in megabytes

         */

        public int readConfiguredMaximum();

        /**

         * Sets the maximum memory parameter (-Xmx) on the gvSIG

         * launch configuration file. Caution: This method directly writes

         * the parameter to the configuration file.

         * 

         * @param maximumMemory The maximum memory, measured in megabytes

         */

        public void saveConguredMaximum(int maximumMemory);

        /**

         * Gets the factory default for maximum memory for gvSIG.

         * 

         * @return

         */

        public int getFactoryDefaultMaximum();

}