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org.apache.openjpa.jdbc.meta.QueryResultMapping Maven / Gradle / Ivy
/*
* 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.openjpa.jdbc.meta;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.lang.StringUtils;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.sql.Joins;
import org.apache.openjpa.lib.meta.SourceTracker;
import org.apache.openjpa.lib.util.Localizer;
import org.apache.openjpa.lib.xml.Commentable;
import org.apache.openjpa.meta.JavaTypes;
import org.apache.openjpa.meta.MetaDataContext;
import org.apache.openjpa.meta.MetaDataModes;
import org.apache.openjpa.util.MetaDataException;
import serp.util.Strings;
/**
* Mapping of a query result set to scalar and/or persistence-capable
* object-level values.
*
* @author Pinaki Poddar
* @author Abe White
*/
public class QueryResultMapping
implements MetaDataModes, SourceTracker, Commentable {
private static final Localizer _loc = Localizer.forPackage
(QueryResultMapping.class);
private final String _name;
private final MappingRepository _repos;
private File _file = null;
private Object _scope = null;
private int _srcType = SRC_OTHER;
private int _lineNum = 0;
private int _colNum = 0;
private int _mode = MODE_QUERY;
private Class _class = null;
private int _idx = 0;
private String[] _comments = null;
private List _colList = null; // list of column ids, typically the column name.
private List _pcList = null;
private PCResult[] _pcs = null;
private Object[] _cols = null;
/**
* Construct with the given name.
*/
QueryResultMapping(String name, MappingRepository repos) {
_name = name;
_repos = repos;
}
/**
* Return the name for this query result.
*/
public String getName() {
return _name;
}
/**
* The class that defines this query result, or null if none.
*/
public Class getDefiningType() {
return _class;
}
/**
* The class that defines this query result, or null if none.
*/
public void setDefiningType(Class cls) {
_class = cls;
}
/**
* Ids of mapped scalar columns in the result. These will typically be
* column names.
*
* @see org.apache.openjpa.jdbc.sql.Result
*/
public Object[] getColumnResults() {
if (_cols == null) {
Object[] cols;
if (_colList == null)
cols = new Object[0];
else
cols = _colList.toArray();
_cols = cols;
}
return _cols;
}
/**
* Add the id of a mapped column in the query result. This will typically
* be a column name.
*
* @see org.apache.openjpa.jdbc.sql.Result
*/
public void addColumnResult(Object id) {
_cols = null;
if (_colList == null) {
_colList = new ArrayList();
}
_colList.add(id);
}
/**
* Return the mapped persistence-capable types in the query result.
*/
public PCResult[] getPCResults() {
if (_pcs == null) {
PCResult[] pcs;
if (_pcList == null) {
pcs = new PCResult[0];
}
else {
pcs = _pcList.toArray(new PCResult[_pcList.size()]);
}
_pcs = pcs;
}
return _pcs;
}
/**
* Add a mapped persistence-capable result with the given candidate type.
*/
public PCResult addPCResult(Class candidate) {
_pcs = null;
PCResult pc = new PCResult(candidate);
if (_pcList == null) {
_pcList = new ArrayList();
}
_pcList.add(pc);
return pc;
}
/**
* The source mode of this query result.
*/
public int getSourceMode() {
return _mode;
}
/**
* The source mode of this query result.
*/
public void setSourceMode(int mode) {
_mode = mode;
}
/**
* Relative order of result mapping in metadata.
*/
public int getListingIndex() {
return _idx;
}
/**
* Relative order of result mapping in metadata.
*/
public void setListingIndex(int idx) {
_idx = idx;
}
public String toString() {
return _name;
}
///////////////
// Commentable
///////////////
public String[] getComments() {
return (_comments == null) ? EMPTY_COMMENTS : _comments;
}
public void setComments(String[] comments) {
_comments = comments;
}
////////////////////////////////
// SourceTracker implementation
////////////////////////////////
public File getSourceFile() {
return _file;
}
public Object getSourceScope() {
return _scope;
}
public int getSourceType() {
return _srcType;
}
public void setSource(File file, Object scope, int srcType) {
_file = file;
_scope = scope;
_srcType = srcType;
}
public String getResourceName() {
return (_class == null) ? _name : _class.getName() + ":" + _name;
}
public int getLineNumber() {
return _lineNum;
}
public void setLineNumber(int lineNum) {
_lineNum = lineNum;
}
public int getColNumber() {
return _colNum;
}
public void setColNumber(int colNum) {
_colNum = colNum;
}
/**
* A persistence-capable result.
*/
public class PCResult {
/**
* Path token to represent a discriminator.
*/
public static final String DISCRIMINATOR = "";
private final Class _candidate;
private ClassMapping _candidateMap = null;
private Map _rawMappings = null;
private Map, ColumnMap> _mappings = null;
private Map, FetchInfo> _eager = null;
private FetchInfo _fetchInfo = null; // for top-level
/**
* Supply candidate type on construction.
*/
private PCResult(Class candidate) {
_candidate = candidate;
}
/**
* The result candidate class.
*/
public Class getCandidateType() {
return _candidate;
}
/**
* Candidate mapping.
*/
public ClassMapping getCandidateTypeMapping() {
if (_candidateMap == null)
_candidateMap = _repos.getMapping(_candidate, null, true);
return _candidateMap;
}
/**
* Return the raw mapping paths supplied with {@link #addMapping}, or
* empty array if none.
*/
public String[] getMappingPaths() {
if (_rawMappings == null) {
return new String[0];
}
Collection keys = _rawMappings.keySet();
return keys.toArray(new String[keys.size()]);
}
/**
* Return the mapping id for the given path supplied with
* {@link #addMapping}, or null if none.
*/
public Object getMapping(String path) {
return (_rawMappings == null) ? null : _rawMappings.get(path);
}
/**
* Map the given path to the given result id.
*/
public void addMapping(String path, Object id) {
if (StringUtils.isEmpty(path))
throw new MetaDataException(_loc.get("null-path",
QueryResultMapping.this, _candidate));
_mappings = null;
_eager = null;
_fetchInfo = null;
if (_rawMappings == null) {
_rawMappings = new HashMap();
}
_rawMappings.put(path, id);
}
/**
* Map the given request onto a result id.
*
* @param path stack of data requests (see
* {@link org.apache.openjpa.jdbc.sql.Result#startDataRequest})
* @param id requested id or column (see
* {@link org.apache.openjpa.jdbc.sql.Result} APIs)
* @param joins requested joins, or null
* @return the id or column to fetch from the result
* (typically a column name)
*/
public Object map(List path, Object id, Joins joins) {
if (_rawMappings == null || !(id instanceof Column)) {
return id;
}
resolve();
ColumnMap cm = _mappings.get(path);
return (cm == null) ? id : cm.map((Column) id);
}
/**
* Return true if the mapped result contains eager data for the given
* field at the given path.
*
* @param path stack of data requests (see
* {@link org.apache.openjpa.jdbc.sql.Result#startDataRequest})
*/
public boolean hasEager(List path, FieldMapping field) {
if (_rawMappings == null) {
return false;
}
resolve();
if (path.isEmpty()) {
return _fetchInfo.eager.get(field.getIndex());
}
if (_eager == null) {
return false;
}
FetchInfo info = _eager.get(path);
return info != null && info.eager.get(field.getIndex());
}
/**
* Return the field indexes to exclude when loading data for the
* given path.
*/
public BitSet getExcludes(List path) {
if (_rawMappings == null) {
return null;
}
resolve();
if (path.isEmpty()) {
return _fetchInfo.excludes;
}
if (_eager == null) {
return null;
}
FetchInfo info = _eager.get(path);
return (info == null) ? null : info.excludes;
}
/**
* Resolve internal datastructures from raw mappings.
*/
private synchronized void resolve() {
if (_rawMappings == null || _mappings != null) {
return;
}
_mappings = new HashMap, ColumnMap>();
_fetchInfo = new FetchInfo(getCandidateTypeMapping());
for(Map.Entry entry : _rawMappings.entrySet()) {
resolveMapping(entry.getKey(), entry.getValue());
}
}
/**
* Resolve the given mapping path.
*/
private void resolveMapping(String path, Object id) {
// build up path to second-to-last token
String[] tokens = Strings.split(path, ".", 0);
List rpath = new ArrayList(tokens.length);
ClassMapping candidate = getCandidateTypeMapping();
FieldMapping fm = null;
for (int i = 0; i < tokens.length - 1; i++) {
fm = candidate.getFieldMapping(tokens[i]);
if (fm == null)
throw new MetaDataException(_loc.get("bad-path",
QueryResultMapping.this, _candidate, path));
if (fm.getEmbeddedMapping() != null) {
recordIncluded(candidate, rpath, fm);
candidate = fm.getEmbeddedMapping();
} else
candidate = fm.getTypeMapping();
if (candidate == null)
throw new MetaDataException(_loc.get("untraversable-path",
QueryResultMapping.this, _candidate, path));
rpath.add(fm);
}
String lastToken = tokens[tokens.length - 1];
if (DISCRIMINATOR.equals(lastToken)) {
Discriminator discrim = candidate.getDiscriminator();
rpath.add(discrim);
assertSingleColumn(discrim.getColumns(), path);
_mappings.put(rpath, new SingleColumnMap(id));
} else {
FieldMapping last = candidate.getFieldMapping(lastToken);
if (last == null)
throw new MetaDataException(_loc.get("untraversable-path",
QueryResultMapping.this, _candidate, path));
Column[] cols = last.getColumns();
assertSingleColumn(cols, path);
Column col = cols[0];
// special-case oid fields, since path lists supplied for
// them at runtime don't include the embedded fields
if (fm != null && fm.getDeclaredTypeCode() == JavaTypes.OID) {
addComplexColumnMapping(fm, rpath, col, id);
return;
}
if (fm != null && fm.getForeignKey() != null) {
// if the last field is one of the joinables used in the
// relation's foreign key, map to relation field path.
// otherwise, record that we have an eager result
Column fkCol = fm.getForeignKey().getColumn(col);
if (fkCol != null)
addComplexColumnMapping(fm, new ArrayList(rpath),
fkCol, id);
else {
recordEager(candidate, rpath, fm);
recordIncluded(candidate, rpath, last);
}
} else
recordIncluded(candidate, rpath, last);
// map to related field path. because the SingleColumnMap
// doesn't test the requested column, it will accept
// requests for both the fk col or the related field col
rpath.add(last);
_mappings.put(rpath, new SingleColumnMap(id));
}
}
/**
* Create an appropriate column mapping for the given field.
*/
private void addComplexColumnMapping(FieldMapping fm, List rpath,
Column col, Object id) {
if (fm.getColumns().length == 1)
_mappings.put(rpath, new SingleColumnMap(id));
else {
MultiColumnMap mcm = (MultiColumnMap) _mappings.get(rpath);
if (mcm == null) {
mcm = new MultiColumnMap(fm.getColumns());
_mappings.put(rpath, mcm);
}
mcm.set(col, id);
}
}
/**
* For now, we only allow mappings with a single column. In the
* future we might introduce a syntax to map multiple columns.
*/
private void assertSingleColumn(Column[] cols, String path) {
if (cols.length != 1)
throw new MetaDataException(_loc.get("num-cols-path",
QueryResultMapping.this, _candidate, path));
}
/**
* Record that there may be eager data for the given field at the given
* path.
*/
private void recordEager(ClassMapping candidate, List path,
FieldMapping fm) {
if (path.size() == 1) {
_fetchInfo.eager.set(fm.getIndex());
_fetchInfo.excludes.clear(fm.getIndex());
} else {
// record at previous path
List copy = new ArrayList(path.size() - 1);
for (int i = 0; i < copy.size(); i++)
copy.add(path.get(i));
if (_eager == null)
_eager = new HashMap, FetchInfo>();
FetchInfo info = _eager.get(copy);
if (info == null) {
info = new FetchInfo(candidate);
_eager.put(copy, info);
}
info.eager.set(fm.getIndex());
info.excludes.clear(fm.getIndex());
}
}
/**
* Record that the field at the given path is included in the results.
*/
private void recordIncluded(ClassMapping candidate, List path,
FieldMapping fm) {
if (path.isEmpty())
_fetchInfo.excludes.clear(fm.getIndex());
else {
if (_eager == null)
_eager = new HashMap, FetchInfo>();
FetchInfo info = _eager.get(path);
if (info == null) {
info = new FetchInfo(candidate);
_eager.put(new ArrayList(path), info);
}
info.excludes.clear(fm.getIndex());
}
}
}
/**
* Fetch information.
*/
private static class FetchInfo {
/**
* Indexes of fields to exclude from loading.
*/
public final BitSet excludes;
/**
* Indexes of eager fields.
*/
public final BitSet eager;
public FetchInfo(ClassMapping type) {
FieldMapping[] fms = type.getFieldMappings();
eager = new BitSet(fms.length);
excludes = new BitSet(fms.length);
for (int i = 0; i < fms.length; i++)
if (!fms[i].isPrimaryKey())
excludes.set(i);
}
}
/**
* Mapping of columns to result ids.
*/
private static interface ColumnMap {
/**
* Return the result id for the given column, or the given colum
* if none.
*/
public Object map(Column col);
}
/**
* {@link ColumnMap} specialized for a single column.
*/
private static class SingleColumnMap
implements ColumnMap {
private final Object _id;
public SingleColumnMap(Object id) {
_id = id;
}
public Object map(Column col) {
return _id;
}
public String toString() {
return _id.toString();
}
}
/**
* {@link ColumnMap} specialized for a multiple columns.
* Maps columns in linear time.
*/
private static class MultiColumnMap
implements ColumnMap {
private final List _cols;
private final Object[] _ids;
public MultiColumnMap(Column[] cols) {
_cols = Arrays.asList(cols);
_ids = new Object[cols.length];
}
public Object map(Column col) {
int idx = _cols.indexOf(col);
return (idx == -1) ? col : _ids[idx];
}
public void set(Column col, Object id) {
int idx = _cols.indexOf(col);
if (idx != -1)
_ids[idx] = id;
}
public String toString() {
return _cols + "=" + Arrays.asList(_ids);
}
}
}
