org.invenzzia.helium.domain.relation.Relationship.java Source code

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Here is the source code for org.invenzzia.helium.domain.relation.Relationship.java

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/*
 * Helium - a set of useful stuff for java.
 * 
 * Helium is free software: you can redistribute it and/or modify
 * it under the terms of the New BSD license as published by
 * Invenzzia Group.
 *
 * Helium is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the new BSD license
 * along with Helium. If not, see <http://invenzzia.org/license/new-bsd>.
 */
package org.invenzzia.helium.domain.relation;

import com.google.common.base.Preconditions;
import com.google.common.collect.LinkedListMultimap;
import com.google.common.collect.Multimap;
import java.util.LinkedHashMap;
import java.util.Map;
import org.invenzzia.helium.domain.MetaRelationship;
import org.invenzzia.helium.domain.exception.RelationshipException;

/**
 * Most of the classes in the domain model are connected by some form of
 * relationship. This class simplifies creating relationships by providing
 * a unified access interface for them that allows the manipulation and
 * retrieval of data. It simplifies the design, and reduces the amount
 * of code and tests that need to be done.
 * 
 * The relationship object requires two generic arguments: master (the
 * owner and subject of the relationship) and servant, which is the object.
 * Each relationship can have many servants but only one master.
 * 
 * @author Tomasz Jdrzejewski
 * @param P master object type
 * @param V servant object type
 */
public class Relationship<P, V> extends BaseRelationship<P, V> {
    public static final int DEFAULT_EXPECTED_KEYS = 100;
    /**
     * Stores 1:n relationship connections.
     */
    private Multimap<P, V> relationship;

    public Relationship(MetaRelationship info) {
        this(info, Relationship.DEFAULT_EXPECTED_KEYS);
    }

    public Relationship(MetaRelationship info, int expectedKeys) {
        super(info);
        this.relationship = LinkedListMultimap.create(expectedKeys);
        this.inverseRelationship = new LinkedHashMap<>(expectedKeys);
    }

    @Override
    public void put(P master, V servant) throws RelationshipException {
        this.filterDuplicates(servant, master.getClass());
        this.relationship.put(master, servant);
        this.putIntoInversedMap(servant, master);
    }

    @Override
    public void update(P newMaster, V servant) throws RelationshipException {
        this.filterNotUpdateable();
        P oldMaster = (P) this.relationshipInfo.getServantParentProperty().getValue(servant);
        if (null == oldMaster) {
            this.put(newMaster, servant);
        } else {
            this.relationship.remove(oldMaster, servant);
            this.relationship.put(newMaster, servant);
            this.putIntoInversedMap(servant, newMaster);
        }
    }

    @Override
    public void remove(P master, V servant) throws RelationshipException {
        this.filterNotAMaster(master, servant);
        if (this.inverseRelationship.remove(servant) != null) {
            this.relationship.remove(master, servant);
            this.relationshipInfo.getServantParentProperty().setValue(servant, null);
        }
    }

    @Override
    public void remove(V servant) {
        P master = (P) this.relationshipInfo.getServantParentProperty().getValue(servant);
        if (this.inverseRelationship.remove(servant) != null) {
            this.relationship.remove(master, servant);
            this.relationshipInfo.getServantParentProperty().setValue(servant, null);
        }
    }

    @Override
    public int sizeFor(P master) {
        return this.relationship.get(master).size();
    }
}