/*
* Copyright 2012 the original author or authors.
*
* 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 org.springframework.data.gemfire.repository.query;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.geode.cache.Region;
import org.springframework.data.domain.Sort;
import org.springframework.data.gemfire.repository.query.support.OqlKeyword;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
/**
* {@link QueryString} is a utility class used to construct GemFire OQL query statement syntax.
*
* @author Oliver Gierke
* @author David Turanski
* @author John Blum
* @see java.util.regex.Pattern
* @see org.springframework.data.domain.Sort
* @see org.springframework.data.gemfire.repository.query.support.OqlKeyword
* @see org.apache.geode.cache.Region
*/
public class QueryString {
protected static final Pattern HINT_PATTERN = Pattern.compile("<HINT '\\w+'(, '\\w+')*>");
protected static final Pattern IMPORT_PATTERN = Pattern.compile("IMPORT .+;");
protected static final Pattern LIMIT_PATTERN = Pattern.compile("LIMIT \\d+");
protected static final Pattern TRACE_PATTERN = Pattern.compile("<TRACE>");
// OQL Query Templates
private static final String HINTS_OQL_TEMPLATE = "<HINT %1$s> %2$s";
private static final String IMPORT_OQL_TEMPLATE = "IMPORT %1$s; %2$s";
private static final String LIMIT_OQL_TEMPLATE = "%1$s LIMIT %2$d";
private static final String SELECT_OQL_TEMPLATE = "SELECT %1$s FROM /%2$s";
private static final String TRACE_OQL_TEMPLATE = "<TRACE> %1$s";
// OQL Query Regular Expression Patterns
private static final String IN_PATTERN = "(?<=IN (SET|LIST) )\\$\\d";
private static final String IN_PARAMETER_PATTERN = "(?<=IN (SET|LIST) \\$)\\d";
private static final String REGION_PATTERN = "\\/(\\/?\\w)+";
private final String query;
/* (non-Javadoc) */
static String asQuery(Class<?> domainType, boolean isCountQuery) {
return String.format(SELECT_OQL_TEMPLATE, (isCountQuery ? "count(*)" : "*"),
validateDomainType(domainType).getSimpleName());
}
/* (non-Javadoc) */
static <T> Class<T> validateDomainType(Class<T> domainType) {
Assert.notNull(domainType, "domainType must not be null");
return domainType;
}
/* (non-Javadoc) */
static String validateQuery(String query) {
Assert.hasText(query, "An OQL Query must be specified");
return query;
}
/**
* Constructs an instance of {@link QueryString} initialized with the given GemFire OQL Query {@link String}.
*
* @param query {@link String} specifying the GemFire OQL Query.
* @throws IllegalArgumentException if the query string is unspecified (null or empty).
*/
public QueryString(String query) {
this.query = validateQuery(query);
}
/**
* Constructs a GemFire OQL {@literal SELECT} Query for the given domain class.
*
* @param domainType application domain object type to query; must not be {@literal null}.
* @see #QueryString(Class, boolean)
*/
@SuppressWarnings("unused")
public QueryString(Class<?> domainType) {
this(domainType, false);
}
/**
* Constructs a GemFire OQL {@literal SELECT} Query for the given domain class. {@code isCountQuery} indicates
* whether to select a count or select the contents of the objects of the given domain object type.
*
* @param domainType application domain object type to query; must not be {@literal null}.
* @param isCountQuery boolean value to indicate if this is a count query.
* @throws IllegalArgumentException if {@code domainType} is null.
* @see #QueryString(String)
*/
public QueryString(Class<?> domainType, boolean isCountQuery) {
this(asQuery(domainType, isCountQuery));
}
/**
* Binds the given {@link Collection} of values into the {@literal IN} parameters of the OQL Query by expanding
* the given values into a comma-separated {@link String}.
*
* @param values the values to bind, returns the {@link QueryString} as is if {@literal null} is given.
* @return a Query String having "in" parameters bound with values.
*/
public QueryString bindIn(Collection<?> values) {
if (values != null) {
return new QueryString(this.query.replaceFirst(IN_PATTERN, String.format("(%s)",
StringUtils.collectionToDelimitedString(values, ", ", "'", "'"))));
}
return this;
}
/**
* Replaces the domain classes referenced inside the current query with the given {@link Region}.
*
* @param domainClass the class type of the GemFire persistent entity to query; must not be {@literal null}.
* @param region the GemFire Region in which to query; must not be {@literal null}.
* @return a Query String with the FROM clause in the OQL statement evaluated and replaced with
* the fully-qualified Region to query.
* @see org.apache.geode.cache.Region
*/
@SuppressWarnings("unused")
public QueryString forRegion(Class<?> domainClass, Region<?, ?> region) {
return new QueryString(this.query.replaceAll(REGION_PATTERN, region.getFullPath()));
}
/**
* Returns the parameter indexes used in this query.
*
* @return the parameter indexes used in this query or an empty {@link Iterable} if none are used.
* @see java.lang.Iterable
*/
public Iterable<Integer> getInParameterIndexes() {
Pattern pattern = Pattern.compile(IN_PARAMETER_PATTERN);
Matcher matcher = pattern.matcher(query);
List<Integer> result = new ArrayList<>();
while (matcher.find()) {
result.add(Integer.parseInt(matcher.group()));
}
return result;
}
/**
* Appends the {@link Sort} order to this GemFire OQL Query string.
*
* @param sort {@link Sort} indicating the order of the query results.
* @return a new {@link QueryString} with an ORDER BY clause if {@link Sort} is not {@literal null},
* or this {@link QueryString} as-is if {@link Sort} is {@literal null}.
* @see org.springframework.data.domain.Sort
* @see org.springframework.data.gemfire.repository.query.QueryString
*/
public QueryString orderBy(Sort sort) {
if (hasSort(sort)) {
StringBuilder orderClause = new StringBuilder("ORDER BY ");
int count = 0;
for (Sort.Order order : sort) {
orderClause.append(count++ > 0 ? ", " : "");
orderClause.append(String.format("%1$s %2$s", order.getProperty(), order.getDirection()));
}
return new QueryString(String.format("%1$s %2$s", makeDistinct(this.query), orderClause.toString()));
}
return this;
}
/* (non-Javadoc) */
private boolean hasSort(Sort sort) {
return (sort != null && sort.iterator().hasNext());
}
/**
* Replaces the SELECT query with a SELECT DISTINCT query if the query does not contain the DISTINCT OQL keyword.
*
* @param query {@link String} containing the query to evaluate.
* @return a SELECT DISTINCT query if {@code query} does not contain the DISTINCT OQL keyword.
*/
String makeDistinct(String query) {
return (query.contains(OqlKeyword.DISTINCT.getKeyword()) ? query
: query.replaceFirst(OqlKeyword.SELECT.getKeyword(),
String.format("%1$s %2$s", OqlKeyword.SELECT.getKeyword(), OqlKeyword.DISTINCT.getKeyword())));
}
/**
* Applies HINTS to the OQL Query.
*
* @param hints array of {@link String Strings} containing query hints.
* @return a new {@link QueryString} if hints are not null or empty, or return this {@link QueryString}.
*/
public QueryString withHints(String... hints) {
if (!ObjectUtils.isEmpty(hints)) {
StringBuilder builder = new StringBuilder();
for (String hint : hints) {
builder.append(builder.length() > 0 ? ", " : "");
builder.append(String.format("'%1$s'", hint));
}
return new QueryString(String.format(HINTS_OQL_TEMPLATE, builder.toString(), query));
}
return this;
}
/**
* Applies an IMPORT to the OQL Query.
*
* @param importExpression {@link String} containing the import clause.
* @return a new {@link QueryString} if an import was declared, or return this {@link QueryString}.
*/
public QueryString withImport(String importExpression) {
return (StringUtils.hasText(importExpression) ?
new QueryString(String.format(IMPORT_OQL_TEMPLATE, importExpression, query)) : this);
}
/**
* Applies a LIMIT to the OQL Query.
*
* @param limit {@link Integer} indicating the number of results to return from the query.
* @return a new {@link QueryString} if a limit was specified, or return this {@link QueryString}.
*/
public QueryString withLimit(Integer limit) {
return (limit != null ? new QueryString(String.format(LIMIT_OQL_TEMPLATE, query, limit)) : this);
}
/**
* Applies TRACE logging to the OQL Query.
*
* @return a new {@link QueryString} with tracing enabled.
*/
public QueryString withTrace() {
return new QueryString(String.format(TRACE_OQL_TEMPLATE, query));
}
/*
* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return query;
}
}