org.n52.movingcode.runtime.codepackage.PID.java Source code

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Here is the source code for org.n52.movingcode.runtime.codepackage.PID.java

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/**
 * Copyright (C) 2012 52North Initiative for Geospatial Open Source Software GmbH
 *
 * 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.n52.movingcode.runtime.codepackage;

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;

/**
 * A immutable class for package IDs
 * 
 * @author matthias
 *
 */
public class PID implements Comparable<PID> {

    public final String name;
    public final DateTime timestamp;

    public PID(final String name, final DateTime timestamp) {
        this.name = name;
        this.timestamp = timestamp;
    }

    /**
     * Parses a packageId of the form
     * my.package.name(version-timestamp)
     * 
     * 
     * @param s
     * @return
     */
    public static final PID fromString(String s) {
        int versionStart = s.lastIndexOf("_");
        String name = s.substring(0, versionStart);
        DateTime timestamp = DateTime.parse(s.substring(versionStart + 1, s.length()));
        return new PID(name, timestamp);
    }

    public boolean isNewerThan(final PID packageId) {
        return timestamp.isAfter(packageId.timestamp);
    }

    /**
     * Canonical String representation of this PID
     * pattern: <name>_<timestamp>
     * 
     * @return
     */
    public String getCanonicalName() {
        return new StringBuilder().append(name).append("_").append(timestamp.withZone(DateTimeZone.UTC).toString())
                .toString();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o instanceof PID) {
            PID otherPID = (PID) o;
            return this.name.equals((otherPID).name) && this.timestamp.isEqual((otherPID).timestamp);
        } else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        int hash = 17;
        hash = hash * 31 + name.hashCode();
        hash = hash * 13 + (int) timestamp.getMillis();
        return hash;
    }

    // TODO: check classes calling this method.
    // if they rely on the canonical String representation
    // they should be calling #getCanonicalName()
    @Override
    public String toString() {
        return new StringBuilder().append(name).append("_").append(timestamp.withZone(DateTimeZone.UTC).toString())
                .toString();
    }

    /**
     * Compares two PID by name and timestamp. The name is evaluated first and compared
     * lexicographically. 
     * 
     * @return
     * 0: both PID are equal
     * +: this PID is greater than the argument
     * -: this PID is smaller than the argument
     * 
     */
    @Override
    public int compareTo(PID other) {
        int retval = this.name.compareTo(other.name);
        if (retval == 0) {
            return this.timestamp.compareTo(other.timestamp);
        } else {
            return retval;
        }
    }

}