/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with this
* work for additional information regarding copyright ownership. The ASF
* licenses this file to You 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.apache.jackrabbit.oak.query;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import org.apache.jackrabbit.oak.api.PropertyValue;
import org.apache.jackrabbit.oak.api.Tree;
import org.apache.jackrabbit.oak.commons.PathUtils;
import org.apache.jackrabbit.oak.namepath.JcrPathParser;
import org.apache.jackrabbit.oak.namepath.NamePathMapper;
import org.apache.jackrabbit.oak.query.ast.AstVisitorBase;
import org.apache.jackrabbit.oak.query.ast.BindVariableValueImpl;
import org.apache.jackrabbit.oak.query.ast.ChildNodeImpl;
import org.apache.jackrabbit.oak.query.ast.ChildNodeJoinConditionImpl;
import org.apache.jackrabbit.oak.query.ast.ColumnImpl;
import org.apache.jackrabbit.oak.query.ast.ComparisonImpl;
import org.apache.jackrabbit.oak.query.ast.ConstraintImpl;
import org.apache.jackrabbit.oak.query.ast.DescendantNodeImpl;
import org.apache.jackrabbit.oak.query.ast.DescendantNodeJoinConditionImpl;
import org.apache.jackrabbit.oak.query.ast.EquiJoinConditionImpl;
import org.apache.jackrabbit.oak.query.ast.FullTextSearchImpl;
import org.apache.jackrabbit.oak.query.ast.FullTextSearchScoreImpl;
import org.apache.jackrabbit.oak.query.ast.LengthImpl;
import org.apache.jackrabbit.oak.query.ast.LiteralImpl;
import org.apache.jackrabbit.oak.query.ast.LowerCaseImpl;
import org.apache.jackrabbit.oak.query.ast.NodeLocalNameImpl;
import org.apache.jackrabbit.oak.query.ast.NodeNameImpl;
import org.apache.jackrabbit.oak.query.ast.OrderingImpl;
import org.apache.jackrabbit.oak.query.ast.PropertyExistenceImpl;
import org.apache.jackrabbit.oak.query.ast.PropertyValueImpl;
import org.apache.jackrabbit.oak.query.ast.SameNodeImpl;
import org.apache.jackrabbit.oak.query.ast.SameNodeJoinConditionImpl;
import org.apache.jackrabbit.oak.query.ast.SelectorImpl;
import org.apache.jackrabbit.oak.query.ast.SourceImpl;
import org.apache.jackrabbit.oak.query.ast.UpperCaseImpl;
import org.apache.jackrabbit.oak.spi.query.Filter;
import org.apache.jackrabbit.oak.spi.query.PropertyValues;
import org.apache.jackrabbit.oak.spi.query.QueryIndex;
import org.apache.jackrabbit.oak.spi.state.NodeState;
import org.apache.jackrabbit.oak.util.TreeUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Represents a parsed query. Lifecycle: use the constructor to create a new
* object. Call init() to initialize the bind variable map. If the query is
* re-executed, a new instance is created.
*/
public class Query {
/**
* The "jcr:path" pseudo-property.
*/
// TODO jcr:path isn't an official feature, support it?
public static final String JCR_PATH = "jcr:path";
/**
* The "jcr:score" pseudo-property.
*/
public static final String JCR_SCORE = "jcr:score";
/**
* The "rep:excerpt" pseudo-property.
*/
public static final String REP_EXCERPT = "rep:excerpt";
private static final Logger LOG = LoggerFactory.getLogger(Query.class);
final SourceImpl source;
final String statement;
final ConstraintImpl constraint;
final HashMap<String, PropertyValue> bindVariableMap = new HashMap<String, PropertyValue>();
final HashMap<String, Integer> selectorIndexes = new HashMap<String, Integer>();
final ArrayList<SelectorImpl> selectors = new ArrayList<SelectorImpl>();
private QueryEngineImpl queryEngine;
private final OrderingImpl[] orderings;
private ColumnImpl[] columns;
private boolean explain, measure;
private long limit = Long.MAX_VALUE;
private long offset;
private long size = -1;
private boolean prepared;
private Tree rootTree;
private NodeState rootState;
private NamePathMapper namePathMapper;
Query(String statement, SourceImpl source, ConstraintImpl constraint, OrderingImpl[] orderings,
ColumnImpl[] columns) {
this.statement = statement;
this.source = source;
this.constraint = constraint;
this.orderings = orderings;
this.columns = columns;
}
public void init() {
final Query query = this;
new AstVisitorBase() {
@Override
public boolean visit(BindVariableValueImpl node) {
node.setQuery(query);
bindVariableMap.put(node.getBindVariableName(), null);
return true;
}
@Override
public boolean visit(ChildNodeImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(ChildNodeJoinConditionImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(ColumnImpl node) {
node.setQuery(query);
return true;
}
@Override
public boolean visit(DescendantNodeImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(DescendantNodeJoinConditionImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(EquiJoinConditionImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(FullTextSearchImpl node) {
node.setQuery(query);
node.bindSelector(source);
return super.visit(node);
}
@Override
public boolean visit(FullTextSearchScoreImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(LiteralImpl node) {
node.setQuery(query);
return true;
}
@Override
public boolean visit(NodeLocalNameImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(NodeNameImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(PropertyExistenceImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(PropertyValueImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(SameNodeImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(SameNodeJoinConditionImpl node) {
node.setQuery(query);
node.bindSelector(source);
return true;
}
@Override
public boolean visit(SelectorImpl node) {
String name = node.getSelectorName();
if (selectorIndexes.put(name, selectors.size()) != null) {
throw new IllegalArgumentException("Two selectors with the same name: " + name);
}
selectors.add(node);
node.setQuery(query);
return true;
}
@Override
public boolean visit(LengthImpl node) {
node.setQuery(query);
return super.visit(node);
}
@Override
public boolean visit(UpperCaseImpl node) {
node.setQuery(query);
return super.visit(node);
}
@Override
public boolean visit(LowerCaseImpl node) {
node.setQuery(query);
return super.visit(node);
}
@Override
public boolean visit(ComparisonImpl node) {
node.setQuery(query);
return super.visit(node);
}
}.visit(this);
source.setQueryConstraint(constraint);
source.init(this);
for (ColumnImpl column : columns) {
column.bindSelector(source);
}
}
public ColumnImpl[] getColumns() {
return columns;
}
public ConstraintImpl getConstraint() {
return constraint;
}
public OrderingImpl[] getOrderings() {
return orderings;
}
public SourceImpl getSource() {
return source;
}
void bindValue(String varName, PropertyValue value) {
bindVariableMap.put(varName, value);
}
public void setLimit(long limit) {
this.limit = limit;
}
public void setOffset(long offset) {
this.offset = offset;
}
public void setExplain(boolean explain) {
this.explain = explain;
}
public void setMeasure(boolean measure) {
this.measure = measure;
}
public ResultImpl executeQuery() {
return new ResultImpl(this);
}
Iterator<ResultRowImpl> getRows() {
prepare();
Iterator<ResultRowImpl> it;
if (explain) {
String plan = getPlan();
columns = new ColumnImpl[] { new ColumnImpl("explain", "plan", "plan")};
ResultRowImpl r = new ResultRowImpl(this,
new String[0],
new PropertyValue[] { PropertyValues.newString(plan)},
null);
it = Arrays.asList(r).iterator();
} else {
if (LOG.isDebugEnabled()) {
LOG.debug("query execute {} ", statement);
LOG.debug("query plan {}", getPlan());
}
if (orderings == null) {
// can apply limit and offset directly
it = new RowIterator(rootState, limit, offset);
} else {
// read and order first; skip and limit afterwards
it = new RowIterator(rootState, Long.MAX_VALUE, 0);
}
long readCount = 0;
if (orderings != null) {
// TODO "order by" is not necessary if the used index returns
// rows in the same order
// avoid overflow (both offset and limit could be Long.MAX_VALUE)
int keep = (int) Math.min(Integer.MAX_VALUE,
Math.min(Integer.MAX_VALUE, offset) +
Math.min(Integer.MAX_VALUE, limit));
ArrayList<ResultRowImpl> list = new ArrayList<ResultRowImpl>();
while (it.hasNext()) {
readCount++;
ResultRowImpl r = it.next();
list.add(r);
// from time to time, sort and truncate
// this should results in O(n*log(2*keep)) operations,
// which is close to the optimum O(n*log(keep))
if (list.size() > keep * 2) {
// remove tail entries right now, to save memory
Collections.sort(list);
keepFirst(list, keep);
}
}
Collections.sort(list);
keepFirst(list, keep);
it = list.iterator();
// skip the head (this is more efficient than removing
// if there are many entries)
for (int i = 0; i < offset && it.hasNext(); i++) {
it.next();
}
size = list.size() - offset;
} else if (measure) {
while (it.hasNext()) {
readCount++;
it.next();
}
}
if (measure) {
columns = new ColumnImpl[] {
new ColumnImpl("measure", "selector", "selector"),
new ColumnImpl("measure", "scanCount", "scanCount")
};
ArrayList<ResultRowImpl> list = new ArrayList<ResultRowImpl>();
ResultRowImpl r = new ResultRowImpl(this,
new String[0],
new PropertyValue[] {
PropertyValues.newString("query"),
PropertyValues.newLong(readCount)
},
null);
list.add(r);
for (SelectorImpl selector : selectors) {
r = new ResultRowImpl(this,
new String[0],
new PropertyValue[] {
PropertyValues.newString(selector.getSelectorName()),
PropertyValues.newLong(selector.getScanCount()),
},
null);
list.add(r);
}
it = list.iterator();
}
}
return it;
}
/**
* Truncate a list.
*
* @param list the list
* @param keep the maximum number of entries to keep
*/
private static void keepFirst(ArrayList<ResultRowImpl> list, int keep) {
while (list.size() > keep) {
// remove the entries starting at the end,
// to avoid n^2 performance
list.remove(list.size() - 1);
}
}
public int compareRows(PropertyValue[] orderValues,
PropertyValue[] orderValues2) {
int comp = 0;
for (int i = 0, size = orderings.length; i < size; i++) {
PropertyValue a = orderValues[i];
PropertyValue b = orderValues2[i];
if (a == null || b == null) {
if (a == b) {
comp = 0;
} else if (a == null) {
// TODO order by: nulls first (it looks like), or low?
comp = -1;
} else {
comp = 1;
}
} else {
comp = a.compareTo(b);
}
if (comp != 0) {
if (orderings[i].isDescending()) {
comp = -comp;
}
break;
}
}
return comp;
}
/**
* Get the query plan. The query must already be prepared.
*
* @return the query plan
*/
private String getPlan() {
return source.getPlan(rootState);
}
void prepare() {
if (prepared) {
return;
}
prepared = true;
source.prepare();
}
/**
* An iterator over result rows.
*/
class RowIterator implements Iterator<ResultRowImpl> {
private final NodeState rootState;
private ResultRowImpl current;
private boolean started, end;
private long limit, offset, rowIndex;
RowIterator(NodeState rootState, long limit, long offset) {
this.rootState = rootState;
this.limit = limit;
this.offset = offset;
}
private void fetchNext() {
if (end) {
return;
}
if (rowIndex >= limit) {
end = true;
return;
}
if (!started) {
source.execute(rootState);
started = true;
}
while (true) {
if (source.next()) {
if (constraint == null || constraint.evaluate()) {
if (offset > 0) {
offset--;
continue;
}
current = currentRow();
rowIndex++;
break;
}
} else {
current = null;
end = true;
break;
}
}
}
@Override
public boolean hasNext() {
if (end) {
return false;
}
if (current == null) {
fetchNext();
}
return !end;
}
@Override
public ResultRowImpl next() {
if (end) {
return null;
}
if (current == null) {
fetchNext();
}
ResultRowImpl r = current;
current = null;
return r;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
ResultRowImpl currentRow() {
int selectorCount = selectors.size();
String[] paths = new String[selectorCount];
for (int i = 0; i < selectorCount; i++) {
SelectorImpl s = selectors.get(i);
paths[i] = s.currentPath();
}
int columnCount = columns.length;
PropertyValue[] values = new PropertyValue[columnCount];
for (int i = 0; i < columnCount; i++) {
ColumnImpl c = columns[i];
values[i] = c.currentProperty();
}
PropertyValue[] orderValues;
if (orderings == null) {
orderValues = null;
} else {
int size = orderings.length;
orderValues = new PropertyValue[size];
for (int i = 0; i < size; i++) {
orderValues[i] = orderings[i].getOperand().currentProperty();
}
}
return new ResultRowImpl(this, paths, values, orderValues);
}
public int getSelectorIndex(String selectorName) {
Integer index = selectorIndexes.get(selectorName);
if (index == null) {
throw new IllegalArgumentException("Unknown selector: " + selectorName);
}
return index;
}
public int getColumnIndex(String columnName) {
for (int i = 0, size = columns.length; i < size; i++) {
ColumnImpl c = columns[i];
String cn = c.getColumnName();
if (cn != null && cn.equals(columnName)) {
return i;
}
}
throw new IllegalArgumentException("Column not found: " + columnName);
}
public PropertyValue getBindVariableValue(String bindVariableName) {
PropertyValue v = bindVariableMap.get(bindVariableName);
if (v == null) {
throw new IllegalArgumentException("Bind variable value not set: " + bindVariableName);
}
return v;
}
public List<SelectorImpl> getSelectors() {
return Collections.unmodifiableList(selectors);
}
public List<String> getBindVariableNames() {
return new ArrayList<String>(bindVariableMap.keySet());
}
public void setQueryEngine(QueryEngineImpl queryEngine) {
this.queryEngine = queryEngine;
}
public QueryIndex getBestIndex(Filter filter) {
return queryEngine.getBestIndex(this, rootState, filter);
}
public void setRootTree(Tree rootTree) {
this.rootTree = rootTree;
}
public void setRootState(NodeState rootState) {
this.rootState = rootState;
}
public void setNamePathMapper(NamePathMapper namePathMapper) {
this.namePathMapper = namePathMapper;
}
public NamePathMapper getNamePathMapper() {
return namePathMapper;
}
public Tree getTree(String path) {
return TreeUtil.getTree(rootTree, PathUtils.isAbsolute(path) ? path.substring(1) : path);
}
/**
* Validate a path is syntactically correct.
*
* @param path the path to validate
*/
public void validatePath(String path) {
if (!JcrPathParser.validate(path)) {
throw new IllegalArgumentException("Invalid path: " + path);
}
}
@Override
public String toString() {
StringBuilder buff = new StringBuilder();
buff.append("select ");
int i = 0;
for (ColumnImpl c : columns) {
if (i++ > 0) {
buff.append(", ");
}
buff.append(c);
}
buff.append(" from ").append(source);
if (constraint != null) {
buff.append(" where ").append(constraint);
}
if (orderings != null) {
buff.append(" order by ");
i = 0;
for (OrderingImpl o : orderings) {
if (i++ > 0) {
buff.append(", ");
}
buff.append(o);
}
}
return buff.toString();
}
public long getSize() {
return size;
}
public String getStatement() {
return statement;
}
}