uk.gov.gchq.gaffer.data.generator.CsvGenerator Maven / Gradle / Ivy
/*
* Copyright 2016-2019 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 com.fasterxml.jackson.annotation.JsonIgnore;
import org.apache.commons.lang3.StringUtils;
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.Collection;
import java.util.LinkedHashMap;
import java.util.regex.Pattern;
/**
* Generates a CSV string for each {@link Element}, based on the fields and constants provided.
*
* For example, if you provide:
* fields=[prop1, SOURCE, DESTINATION, prop2, GROUP] and constants=["constant1", "constant2"]
*
* The output will be:
* prop1Value,sourceValue,destinationValue,prop2,groupValue,constant1,constant2
*
*/
@Since("1.0.0")
@Summary("Generates a CSV string for each element")
public class CsvGenerator implements OneToOneObjectGenerator {
public static final String GROUP = "GROUP";
public static final String COMMA = ",";
private static final Pattern COMMA_PATTERN = Pattern.compile(COMMA);
private static final String COMMA_REPLACEMENT_DEFAULT = " ";
private LinkedHashMap fields = new LinkedHashMap<>();
private LinkedHashMap constants = new LinkedHashMap<>();
/**
* When set to true, each value in the csv will be wrapped in quotes.
*/
private boolean quoted = false;
/**
* Replaces commas with this string. If null then no replacement is done.
*/
private String commaReplacement = COMMA_REPLACEMENT_DEFAULT;
/**
* 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;
}
@Override
public String _apply(final Element element) {
final StringBuilder strBuilder = new StringBuilder();
for (final String field : fields.keySet()) {
final Object value = getFieldValue(element, field);
if (null != value) {
strBuilder.append(quoteString(value));
}
strBuilder.append(COMMA);
}
if (!constants.isEmpty()) {
for (final String constant : constants.keySet()) {
strBuilder.append(quoteString(constant));
strBuilder.append(COMMA);
}
}
if (strBuilder.length() < 1) {
return "";
}
return strBuilder.substring(0, strBuilder.length() - 1);
}
/**
* Generates a CSV String from, if present, the fields and constants
*
* @return a CSV String of all fields, or constants, or both.
*/
@JsonIgnore
public String getHeader() {
if (fields.isEmpty()) {
if (constants.isEmpty()) {
return "";
}
return getHeaderFields(constants.values());
}
if (constants.isEmpty()) {
return getHeaderFields(fields.values());
}
return getHeaderFields(fields.values()) + COMMA + getHeaderFields(constants.values());
}
private String getHeaderFields(final Collection fields) {
return StringUtils.join(fields.stream().map(this::quoteString).toArray(), COMMA);
}
private String quoteString(final Object s) {
String value;
if (null == s) {
value = "";
} else {
value = s.toString();
}
if (null != commaReplacement) {
value = COMMA_PATTERN.matcher(value).replaceAll(commaReplacement);
}
if (quoted) {
value = "\"" + value + "\"";
}
return value;
}
public boolean isQuoted() {
return quoted;
}
public void setQuoted(final boolean quoted) {
this.quoted = quoted;
}
public String getCommaReplacement() {
return commaReplacement;
}
public void setCommaReplacement(final String commaReplacement) {
this.commaReplacement = commaReplacement;
}
public static class Builder {
private LinkedHashMap fields = new LinkedHashMap<>();
private LinkedHashMap constants = new LinkedHashMap<>();
private String commaReplacement = COMMA_REPLACEMENT_DEFAULT;
private Boolean quoted;
/**
* Stores the group of an {@link Element}.
*
* @param columnHeader the group of the {@code Element}
* @return a new {@link Builder}
*/
public Builder group(final String columnHeader) {
fields.put(GROUP, columnHeader);
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 columnHeader the value of the property
* @return a new {@link Builder}
*/
public Builder property(final String propertyName, final String columnHeader) {
fields.put(propertyName, columnHeader);
return this;
}
/**
* Stores the Vertex of an {@link uk.gov.gchq.gaffer.data.element.Entity}
*
* @param columnHeader the vertex contained within the {@code Entity}
* @return a new {@link Builder}
*/
public Builder vertex(final String columnHeader) {
return identifier(IdentifierType.VERTEX, columnHeader);
}
/**
* Stores the Source Vertex of an {@link uk.gov.gchq.gaffer.data.element.Edge}.
*
* @param columnHeader the source vertex
* @return a new {@link Builder}
*/
public Builder source(final String columnHeader) {
return identifier(IdentifierType.SOURCE, columnHeader);
}
/**
* Stores the Destination Vertex of an {@link uk.gov.gchq.gaffer.data.element.Entity}
*
* @param columnHeader the destination vertex
* @return a new {@link Builder}
*/
public Builder destination(final String columnHeader) {
return identifier(IdentifierType.DESTINATION, columnHeader);
}
/**
* Stores the Direction flag, indicating whether or not the {@link uk.gov.gchq.gaffer.data.element.Edge}
* is directed.
*
* @param columnHeader true or false for if the {@code Edge} is directed or not
* @return a new {@link Builder}
*/
public Builder direction(final String columnHeader) {
return identifier(IdentifierType.DIRECTED, columnHeader);
}
/**
* 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 columnHeader the value for the corresponding field
* @return a new {@link Builder}
*/
public Builder identifier(final IdentifierType identifierType, final String columnHeader) {
fields.put(identifierType.name(), columnHeader);
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;
}
/**
* Stores the String with which any encountered commas will be replaced.
*
* @param commaReplacement the replacement String
* @return a new {@link Builder}
*/
public Builder commaReplacement(final String commaReplacement) {
this.commaReplacement = commaReplacement;
return this;
}
/**
* Stores the flag for whether or not each distinct value should be wrapped in quotation marks.
*
* @param quoted true or false
* @return a new {@link Builder}
*/
public Builder quoted(final boolean quoted) {
this.quoted = quoted;
return this;
}
/**
* Passes all of the configured fields and constants about an {@link Element} to a new {@link CsvGenerator},
* including the comma replacement String, and the flag for whether values should be quoted.
*
* @return a new {@code CsvGenerator}, containing all configured information
*/
public CsvGenerator build() {
final CsvGenerator generator = new CsvGenerator();
generator.setFields(fields);
generator.setConstants(constants);
generator.setCommaReplacement(commaReplacement);
if (null != quoted) {
generator.setQuoted(quoted);
}
return generator;
}
}
}
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