uk.gov.gchq.gaffer.data.generator.MapGenerator Maven / Gradle / Ivy
/*
* Copyright 2016-2020 Crown Copyright
*
* 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 uk.gov.gchq.gaffer.data.generator;
import uk.gov.gchq.gaffer.data.element.Element;
import uk.gov.gchq.gaffer.data.element.IdentifierType;
import uk.gov.gchq.koryphe.Since;
import uk.gov.gchq.koryphe.Summary;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* A {@code MapGenerator} is a generator which creates a representation of an {@link Element}
* using a {@link LinkedHashMap}.
*
* For example, providing an {@link uk.gov.gchq.gaffer.data.element.Edge} with fields:
*
* - Group: "EdgeGroup"
* - Source: "A"
* - Destination: "B"
* - Directed: true
* - Property1: "propValue"
*
* The generator will store these in a {@code LinkedHashMap}, for which the fields will be represented as:
*
* {
* GROUP: "EdgeGroup",
* SOURCE: "A",
* DESTINATION: "B",
* DIRECTED: "true"
* PROPERTY1: "propValue"
* }
*
* Any constants relevant to a particular {@code Element} can be added,
* and will be stored in a separate {@code LinkedHashMap}.
*/
@Since("1.0.0")
@Summary("Generates a Map for each element")
public class MapGenerator implements OneToOneObjectGenerator> {
public static final String GROUP = "GROUP";
private LinkedHashMap fields = new LinkedHashMap<>();
private LinkedHashMap constants = new LinkedHashMap<>();
@Override
public Map _apply(final Element element) {
final Map map = new LinkedHashMap<>(fields.size() + constants.size());
for (final Map.Entry entry : fields.entrySet()) {
final Object value = getFieldValue(element, entry.getKey());
if (null != value) {
map.put(entry.getValue(), value);
}
}
map.putAll(constants);
return map;
}
/**
* Attempts to find the value of a field from a given {@link Element},
* corresponding to a provided key, where the key is the name of the field.
*
* @param element the Element from which to retrieve a field value
* @param key the name of the field to be retrieved
* @return the value of the field
*/
private Object getFieldValue(final Element element, final String key) {
final IdentifierType idType = IdentifierType.fromName(key);
final Object value;
if (null == idType) {
if (GROUP.equals(key)) {
value = element.getGroup();
} else {
value = element.getProperty(key);
}
} else {
value = element.getIdentifier(idType);
}
return value;
}
public LinkedHashMap getFields() {
return fields;
}
public void setFields(final LinkedHashMap fields) {
if (null == fields) {
this.fields = new LinkedHashMap<>();
}
this.fields = fields;
}
public LinkedHashMap getConstants() {
return constants;
}
public void setConstants(final LinkedHashMap constants) {
if (null == constants) {
this.constants = new LinkedHashMap<>();
}
this.constants = constants;
}
public static class Builder {
private LinkedHashMap fields = new LinkedHashMap<>();
private LinkedHashMap constants = new LinkedHashMap<>();
/**
* Stores the group of an {@link Element}.
*
* @param mapKey the group of the {@code Element}
* @return a new {@link Builder}
*/
public Builder group(final String mapKey) {
fields.put(GROUP, mapKey);
return this;
}
/**
* Stores any additional properties of an {@link Element}.
* For example: property("count", "3").
* This would add the "count" property with a value of "3".
*
* @param propertyName the name of the property
* @param mapKey the value of the property
* @return a new {@link Builder}
*/
public Builder property(final String propertyName, final String mapKey) {
fields.put(propertyName, mapKey);
return this;
}
/**
* Stores the Vertex of an {@link uk.gov.gchq.gaffer.data.element.Entity}.
*
* @param mapKey the vertex contained within the {@code Entity}
* @return a new {@link Builder}
*/
public Builder vertex(final String mapKey) {
return identifier(IdentifierType.VERTEX, mapKey);
}
/**
* Stores the Source Vertex of an {@link uk.gov.gchq.gaffer.data.element.Edge}.
*
* @param mapKey the source vertex
* @return a new {@link Builder}
*/
public Builder source(final String mapKey) {
return identifier(IdentifierType.SOURCE, mapKey);
}
/**
* Stores the Destination Vertex of an {@link uk.gov.gchq.gaffer.data.element.Edge}
*
* @param mapKey the destination vertex
* @return a new {@link Builder}
*/
public Builder destination(final String mapKey) {
return identifier(IdentifierType.DESTINATION, mapKey);
}
/**
* Stores the Direction flag, indicating whether or not the {@link uk.gov.gchq.gaffer.data.element.Edge}
* is directed.
*
* @param mapKey true or false for if the {@code Edge} is directed or not
* @return a new {@link Builder}
*/
public Builder direction(final String mapKey) {
return identifier(IdentifierType.DIRECTED, mapKey);
}
/**
* Allows an {@link IdentifierType} of an {@link Element} to be stored, such as
* an {@link uk.gov.gchq.gaffer.data.element.Edge}'s {@link IdentifierType#MATCHED_VERTEX}.
*
* @param identifierType the {@code IdentifierType} of the {@code Element}
* @param mapKey the value for the corresponding field
* @return a new {@link Builder}
*/
public Builder identifier(final IdentifierType identifierType, final String mapKey) {
fields.put(identifierType.name(), mapKey);
return this;
}
/**
* Stores any constants specific to a given {@link Element}.
*
* @param key the name of the constant
* @param value the value of the constant
* @return a new {@link Builder}
*/
public Builder constant(final String key, final String value) {
constants.put(key, value);
return this;
}
/**
* Passes all of the configured information about an {@link Element} into a new {@link MapGenerator}
*
* @return a new {@code MapGenerator}, containing all fields and constants
*/
public MapGenerator build() {
final MapGenerator generator = new MapGenerator();
generator.setFields(fields);
generator.setConstants(constants);
return generator;
}
}
}