001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 */
019package org.apache.isis.viewer.restfulobjects.rendering;
020
021import java.util.Collections;
022import java.util.List;
023
024import org.apache.isis.viewer.restfulobjects.applib.JsonRepresentation;
025import org.apache.isis.viewer.restfulobjects.applib.util.PathNode;
026import org.apache.isis.viewer.restfulobjects.rendering.util.FollowSpecUtil;
027
028import com.google.common.collect.Lists;
029
030public final class LinkFollowSpecs {
031
032    public final static LinkFollowSpecs create(final List<List<String>> links) {
033        final List<List<PathNode>> specs = FollowSpecUtil.asFollowSpecs(links);
034        return new LinkFollowSpecs(specs, Mode.FOLLOWING, null);
035    }
036
037    private enum Mode {
038        FOLLOWING, TERMINATED;
039    }
040
041    private final List<List<PathNode>> pathSpecs;
042    private final Mode mode;
043    // don't care about the key, just the criteria
044    private final List<PathNode> criteriaSpecs;
045
046    private LinkFollowSpecs(final List<List<PathNode>> pathSpecs, final Mode mode, final List<PathNode> criteriaSpecs) {
047        this.pathSpecs = pathSpecs;
048        this.mode = mode;
049        this.criteriaSpecs = criteriaSpecs;
050    }
051
052    /**
053     * A little algebra...
054     */
055    public LinkFollowSpecs follow(final String pathTemplate, final Object... args) {
056        final String path = String.format(pathTemplate, args);
057        if (path == null) {
058            return terminated();
059        }
060        if (mode == Mode.TERMINATED) {
061            return terminated();
062        }
063        final PathNode candidate = PathNode.parse(path);
064        if (mode == Mode.FOLLOWING) {
065            List<List<PathNode>> remainingPathSpecs = Lists.newArrayList();
066            List<PathNode> firstSpecs = Lists.newArrayList();
067            for(List<PathNode> spec: pathSpecs) {
068                if(spec.isEmpty()) {
069                    continue;
070                }
071                PathNode first = spec.get(0);
072                if(candidate.equals(first)) {
073                    List<PathNode> remaining = spec.subList(1, spec.size());
074                    firstSpecs.add(first);
075                    remainingPathSpecs.add(remaining);
076                }
077            }
078            if(!remainingPathSpecs.isEmpty()) {
079                return new LinkFollowSpecs(remainingPathSpecs, Mode.FOLLOWING, firstSpecs);
080            }
081            return terminated();
082        }
083        return terminated();
084    }
085
086    private static LinkFollowSpecs terminated() {
087        return new LinkFollowSpecs(Collections.<List<PathNode>>emptyList(), Mode.TERMINATED, Collections.<PathNode>emptyList());
088    }
089
090    /**
091     * Not public API; use {@link #matches(JsonRepresentation)}.
092     */
093    boolean isFollowing() {
094        return mode == Mode.FOLLOWING;
095    }
096
097    public boolean isTerminated() {
098        return mode == Mode.TERMINATED;
099    }
100
101    /**
102     * Ensure that every key present in the provided map matches the criterium.
103     * 
104     * <p>
105     * Any keys in the criterium are ignored (these were matched on during the
106     * {@link #follow(String, Object...)} call).
107     */
108    public boolean matches(final JsonRepresentation jsonRepr) {
109        if (!isFollowing()) {
110            return false;
111        }
112        if(criteriaSpecs == null) {
113            return true;
114        }
115        for (PathNode criteriaSpec : criteriaSpecs) {
116            if(criteriaSpec.matches(jsonRepr)) {
117                return true;
118            }
119        }
120        return false;
121    }
122
123    @Override
124    public String toString() {
125        return mode + " : " + criteriaSpecs + " : " + pathSpecs;
126    }
127
128}