| package org.apache.rya.indexing; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| |
| import java.io.UnsupportedEncodingException; |
| |
| /** |
| * A time with beginning and end date and time, which could be indefinitely in |
| * the past or future. Immutable, so it's thread safe. For use in reading and |
| * writing from Rya's temporal indexing scheme. |
| * |
| */ |
| public class TemporalInterval implements Comparable<TemporalInterval> { |
| |
| // the beginning and end. Read-only because they are final references to immutable objects. |
| private final TemporalInstant hasBeginning; |
| private final TemporalInstant hasEnd; |
| |
| /** |
| * Separate the beginning and end with this. |
| * Used because Joda time library's interval uses this. |
| * TODO: Move this down to the TemporalInterval implementation. |
| * TODO: Then add a TemporalInterval.keyConcatenate(). |
| */ |
| public static final String DELIMITER = "/"; |
| |
| // /** |
| // * Empty constructor -- not allowed, no defaults. |
| // * For an infinite span of time: do it like this: |
| // * new TemporalInterval(TemporalInstantImpl.getMinimum, TemporalInstantImpl.getMaximum) |
| // */ |
| // public TemporalInterval() { |
| // hasBeginning = null; |
| // hasEnd = null; |
| // } |
| |
| /** |
| * Constructor setting beginning and end with an implementation of {@link TemporalInstant}. |
| * beginning must be less than end. |
| * |
| * @param hasBeginning |
| * @param hasEnd |
| */ |
| public TemporalInterval(TemporalInstant hasBeginning, TemporalInstant hasEnd) { |
| super(); |
| if (hasBeginning != null && hasEnd != null && 0 < hasBeginning.compareTo(hasEnd)) |
| throw new IllegalArgumentException("The Beginning instance must not compare greater than the end."); |
| this.hasBeginning = hasBeginning; |
| this.hasEnd = hasEnd; |
| } |
| |
| /** |
| * @return the hasBeginning |
| */ |
| public TemporalInstant getHasBeginning() { |
| return hasBeginning; |
| } |
| |
| /** |
| * @return the hasEnd |
| */ |
| public TemporalInstant getHasEnd() { |
| return hasEnd; |
| } |
| |
| /** |
| * True if CompareTo() says equal (0) |
| */ |
| @Override |
| public boolean equals(Object other) { |
| return other instanceof TemporalInterval |
| && this.compareTo((TemporalInterval) other) == 0; |
| }; |
| |
| /** |
| * Compare beginnings, if the same then compare ends, or equal if beginnings equal and endings equal. |
| * Nulls represent infinity. |
| */ |
| @Override |
| public int compareTo(TemporalInterval other) { |
| int compBegins = this.hasBeginning.compareTo(other.hasBeginning); |
| if (0 == compBegins) |
| return this.hasEnd.compareTo(other.hasEnd); |
| else |
| return compBegins; |
| |
| } |
| |
| /** |
| * Hashcode for |
| */ |
| @Override |
| public int hashCode() { |
| if (hasBeginning == null) |
| if (hasEnd == null) |
| return 0; |
| else |
| return hasEnd.hashCode(); |
| else |
| return hashboth(this.hasBeginning.hashCode(), |
| this.hasEnd.hashCode()); |
| } |
| |
| /** |
| * Hashcode combining two string hashcodes. |
| */ |
| protected static int hashboth(int i1, int i2) { |
| // return (int) (( 1L * i1 * i2) ; % (1L + Integer.MAX_VALUE)); |
| // let the overflow happen. It won't throw an error. |
| return (i1 + i2); |
| } |
| |
| /** |
| * Get the key use for rowid for the beginning of the interval. Use ascii |
| * for conversion to catch and prevent multi-byte chars. |
| * |
| * @return |
| */ |
| public byte[] getAsKeyBeginning() { |
| try { |
| return (hasBeginning.getAsKeyString() + DELIMITER + hasEnd |
| .getAsKeyString()).getBytes("US-ASCII"); |
| } catch (UnsupportedEncodingException e) { |
| // this is a code error, the strings are mostly numbers. |
| throw new Error("while converting key string to ascii bytes", e); |
| } |
| } |
| |
| /** |
| * get the key used for indexing the end of the interval. Use ascii for |
| * conversion to catch and prevent multi-byte chars. |
| * |
| * @return |
| */ |
| public byte[] getAsKeyEnd() { |
| try { |
| return (hasEnd.getAsKeyString() + DELIMITER + hasBeginning |
| .getAsKeyString()).getBytes("US-ASCII"); |
| } catch (UnsupportedEncodingException e) { |
| // this is a code error, the strings are mostly numbers and ascii |
| // symbols. |
| throw new Error("while converting key string to ascii bytes", e); |
| } |
| } |
| |
| /** |
| * Format as a "period" in this paper. This is not a standard, really. |
| * http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.298.8948&rep=rep1&type=pdf |
| * also consider using the typed literal syntax: |
| * "[2010-01-01,2010-01-31]"^^xs:period |
| * @return [begindate,enddate] for example: [2010-01-01,2010-01-31] |
| * |
| */ |
| public String getAsPair() { |
| return "["+hasBeginning.getAsReadable() + "," + hasEnd.getAsReadable() + "]"; |
| } |
| |
| @Override |
| public String toString() { |
| return getAsPair() ; |
| // return hasBeginning.getAsReadable() + DELIMITER + hasEnd.getAsReadable(); |
| } |
| } |