001/** 002 * Copyright 2015 DuraSpace, Inc. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016package org.fcrepo.http.commons.api.rdf; 017 018import java.util.Comparator; 019 020import com.hp.hpl.jena.graph.Triple; 021import com.hp.hpl.jena.shared.PrefixMapping; 022 023/** 024 * Comparator to sort a list of Quads by subject, predicate, and object 025 * to ensure a consistent order for human-readable output 026 * 027 * @author awoods 028 */ 029public class TripleOrdering implements Comparator<Triple> { 030 031 private final PrefixMapping prefixMapping; 032 033 /** 034 * When sorting predicates, take into account the given PrefixMapping 035 * @param prefixMapping the prefix mapping 036 */ 037 public TripleOrdering(final PrefixMapping prefixMapping) { 038 super(); 039 040 this.prefixMapping = prefixMapping; 041 } 042 043 @Override 044 public int compare(final Triple left, final Triple right) { 045 046 final int s = 047 left.getSubject().toString(prefixMapping, false).compareTo( 048 right.getSubject().toString(prefixMapping, false)); 049 050 if (s != 0) { 051 return s; 052 } 053 054 final int p = 055 left.getPredicate().toString(prefixMapping, false).compareTo( 056 right.getPredicate().toString(prefixMapping, false)); 057 058 if (p != 0) { 059 return p; 060 } 061 062 return left.getObject().toString(false).compareTo( 063 right.getObject().toString(false)); 064 065 } 066 067}