source: events/src/main/java/geniusweb/actions/FileLocation.java@ 42

package geniusweb.actions;

import java.io.File;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.UUID;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonValue;

/**
 * This contains a "system independent" {@link File}. This is represented by a
 * {@link UUID}. See {@link #getFile()} to get the file referenced by this. The
 * file may or may not yet exist (depending on whether your party already wrote
 * some contents in that file in previous runs), may or may not be empty (your
 * choice), and can contain any type of data. The original intent of this is
 * that parties can store learned data in this file, while the name can be kept
 * for later re-use in later runs (eg negotiation sessions) on the same machine.
 * <p>
 * This file is to be used locally on some other machine (typically a
 * partiesserver). This object itself only contains a file name.
 * {@link #getFile()} turns it into a system-specific {@link File}. <br>
 * <h2>WARNING</h2> if used multiple times on different machines, multiple,
 * separate files will be involved, there is no magical synchronization of
 * multiple items with the same UUID used on different machines.
 */
public class FileLocation {

        @JsonValue
        private final UUID name;

        private final static String TMP = System.getProperty("java.io.tmpdir");
        private final static String GENIUSWEB = "geniusweb";
        private final static Path rootpath = Paths.get(TMP, GENIUSWEB);
        private final static File rootfolder = rootpath.toFile();

        /**
         * @param name the name of the file (must be UUID to prevent injection of
         *             bad filenames like /.. or C:) Use {@link #FileLocation()} to
         *             create new FileLocation. That should ensure a new UUID that
         *             does not collide with existing ones.
         */
        @JsonCreator
        public FileLocation(UUID name) {
                if (!rootfolder.exists()) {
                        rootfolder.mkdir();
                        System.out
                                        .println("created FileLocation root dir at " + rootfolder);
                }

                this.name = name;
        }

        /**
         * Creates a new "random" FileLocation.
         */
        public FileLocation() {
                this(UUID.randomUUID());
        }

        /**
         * @return the UUID string
         */
        public String getUUIDString() {
                return name.toString();
        }

        /**
         * 
         * @return Actual file that can be used for read/write operations. This file
         *         usually resides in the geniusweb folder inside the java.io.tmpdir
         *         system property. This temp dir depends on the run configuration,
         *         eg some directory inside the user's home directory, or a temp
         *         folder inside tomcat.
         */
        public File getFile() {
                return Paths.get(TMP, GENIUSWEB, name.toString()).toFile();
        }

        @Override
        public String toString() {
                return "FileLocation[" + name + "]";
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result + ((name == null) ? 0 : name.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                FileLocation other = (FileLocation) obj;
                if (name == null) {
                        if (other.name != null)
                                return false;
                } else if (!name.equals(other.name))
                        return false;
                return true;
        }
}