com.google.apphosting.utils.config.IndexesXml Maven / Gradle / Ivy
/*
* Copyright 2021 Google LLC
*
* 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
*
* https://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 com.google.apphosting.utils.config;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Parsed datastore-indexes.xml file.
*
* Any additions to this class should also be made to the YAML
* version in IndexYamlReader.java.
*
*/
public class IndexesXml implements Iterable{
// Shared XML/YAML constants.
public static final String DIRECTION_VALUE_ASC = "asc";
public static final String DIRECTION_VALUE_DESC = "desc";
public static final String MODE_VALUE_GEOSPATIAL = "geospatial";
/**
* A simple value object, encapsulating the specification of the
* part of the index configuration attributable to a single
* property.
*/
public static class PropertySort {
private final String propName;
private final String direction;
private final String mode;
// TODO: rename this class, because it's now encapsulating
// more than just the sort order (of a Property's contribution to
// an index).
public PropertySort(String propName, String direction, String mode) {
this.propName = propName;
this.direction = direction;
this.mode = mode;
}
public String getPropertyName() {
return propName;
}
public String getDirection() {
return direction;
}
public String getMode() {
return mode;
}
}
/**
* The type of index.
*
* This is needed during parsing and validation. The type is not explicitly mentioned in the
* XML, but must be inferred from the presence of various attributes. Once the type is
* established, it constrains the attributes the may appear in the rest of the index
* configuration.
*/
// TODO: consider representing by proper subclasses of class Index
public enum Type {
/**
* A traditional Datastore index, with properties appearing in
* ascending or descending order.
*/
ORDERED,
/**
* An index supporting 2-dimensional distance queries on points on
* the surface of the Earth.
*/
GEO_SPATIAL
};
/**
*/
public static class Index {
private final String kind;
private final Boolean ancestors;
private final List properties;
public Index(String kind, Boolean ancestors) {
this.kind = kind;
this.ancestors = ancestors;
this.properties = new ArrayList();
}
public void addNewProperty(String name, String direction, String mode) {
properties.add(new PropertySort(name, direction, mode));
}
public String getKind() {
return kind;
}
public boolean doIndexAncestors() {
return ancestors;
}
public List getProperties() {
return properties;
}
public String toYaml() {
return toLocalStyleYaml();
}
/**
* Builds a Yaml String representing this index, using the style of Yaml
* generation appropriate for a local indexes.yaml files.
* @return A Yaml String
*/
private String toLocalStyleYaml(){
StringBuilder builder = new StringBuilder(50 * (1 + properties.size()));
builder.append("- kind: \"" + kind + "\"\n");
if (Boolean.TRUE.equals(ancestors)) {
builder.append(" ancestor: yes\n");
}
if (!properties.isEmpty()) {
builder.append(" properties:\n");
for (PropertySort prop : properties) {
builder.append(" - name: \"" + prop.getPropertyName() + "\"\n");
if (prop.getDirection() != null) {
builder.append(" direction: " + prop.getDirection() + "\n");
}
if (prop.getMode() != null) {
builder.append(" mode: " + prop.getMode() + "\n");
}
}
}
return builder.toString();
}
/**
* Builds a Yaml string representing this index, mimicking the style of Yaml
* generation used on the admin server. Since the admin server is written in
* python, it generates a slightly different style of yaml. This method is
* useful only for testing that the client-side code is able to parse this
* style of yaml.
*
* @return An admin-server-style Yaml String.
*/
private String toServerStyleYaml() {
StringBuilder builder = new StringBuilder(50 * (1 + properties.size()));
builder.append("- ").append(IndexYamlReader.INDEX_TAG).append("\n");
builder.append(" kind: " + kind + "\n");
if (Boolean.TRUE.equals(ancestors)) {
builder.append(" ancestor: yes\n");
}
if (!properties.isEmpty()) {
builder.append(" properties:\n");
for (PropertySort prop : properties) {
builder.append(" - ");
builder.append(IndexYamlReader.PROPERTY_TAG);
builder.append(" {");
if (prop.getDirection() != null) {
builder.append("direction: ");
builder.append(prop.getDirection());
builder.append(",\n");
}
if (prop.getMode() != null) {
builder.append("mode: ");
builder.append(prop.getMode());
builder.append(",\n");
}
builder.append(" ");
builder.append("name: " + prop.getPropertyName());
builder.append("}\n");
}
}
return builder.toString();
}
public String toXmlString() {
StringBuilder builder = new StringBuilder(100 * (1 + properties.size()));
String ancestorAttribute = ancestors == null ? ""
: String.format(" ancestor=\"%s\"", ancestors);
builder.append("\n");
for (PropertySort prop : properties) {
builder.append(" \n");
return builder.toString();
}
}
private final List indexes;
public IndexesXml() {
indexes = new ArrayList();
}
@Override
public Iterator iterator() {
return indexes.iterator();
}
public int size(){
return indexes.size();
}
public Index addNewIndex(String kind, Boolean ancestors) {
Index index = new Index(kind, ancestors);
indexes.add(index);
return index;
}
/**
* Adds the given {@link Index} to the collection
* contained in this object. Note that given {@link Index}
* is not cloned. The provided object instance will become
* incorporated into this object's collection.
* @param index
*/
public void addNewIndex(Index index){
indexes.add(index);
}
public String toYaml() {
return toYaml(false);
}
/**
* Builds yaml string representing the indexes
*
* @param serverStyle Use the admin server style of yaml generation. Since the
* admin server is written in python, it generates a slightly different
* style of yaml. Setting this parameter to {@code true} is useful only
* for testing that the client-side code is able to parse this style of
* yaml.
* @return A Yaml string.
*/
public String toYaml(boolean serverStyle) {
StringBuilder builder = new StringBuilder(1024);
if (serverStyle) {
builder.append(IndexYamlReader.INDEX_DEFINITIONS_TAG).append("\n");
}
builder.append("indexes:");
int numIndexes = (null == indexes ? 0 : indexes.size());
if (0 == numIndexes && serverStyle) {
builder.append(" []");
}
builder.append("\n");
for (Index index : indexes) {
String indexYaml = (serverStyle ? index.toServerStyleYaml() : index.toLocalStyleYaml());
builder.append(indexYaml);
}
return builder.toString();
}
}