| /* |
| * 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.strats; |
| |
| import java.lang.reflect.Modifier; |
| import java.sql.Types; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.TreeSet; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| |
| import org.apache.openjpa.jdbc.kernel.JDBCStore; |
| import org.apache.openjpa.jdbc.meta.ClassMapping; |
| import org.apache.openjpa.jdbc.meta.Discriminator; |
| import org.apache.openjpa.jdbc.meta.DiscriminatorMappingInfo; |
| import org.apache.openjpa.jdbc.schema.Column; |
| import org.apache.openjpa.jdbc.schema.Schemas; |
| import org.apache.openjpa.lib.util.Localizer; |
| import org.apache.openjpa.meta.JavaTypes; |
| import org.apache.openjpa.util.MetaDataException; |
| |
| /** |
| * Maps metadata-given values to classes. |
| * |
| * @author Abe White |
| */ |
| public class ValueMapDiscriminatorStrategy |
| extends InValueDiscriminatorStrategy { |
| |
| private static final long serialVersionUID = 1L; |
| |
| public static final String ALIAS = "value-map"; |
| |
| private static final Localizer _loc = Localizer.forPackage |
| (ValueMapDiscriminatorStrategy.class); |
| |
| private Map<String, Class<?>> _vals; |
| private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock(true); |
| private final Lock _readLock = rwl.readLock(); |
| private final Lock _writeLock = rwl.writeLock(); |
| |
| @Override |
| public String getAlias() { |
| return ALIAS; |
| } |
| |
| @Override |
| protected int getJavaType() { |
| Object val = disc.getValue(); |
| if (val != null && val != Discriminator.NULL) |
| return JavaTypes.getTypeCode(val.getClass()); |
| |
| // if the user wants the type to be null, we need a jdbc-type |
| // on the column or an existing column to figure out the java type |
| DiscriminatorMappingInfo info = disc.getMappingInfo(); |
| List<Column> cols = info.getColumns(); |
| Column col = (cols.isEmpty()) ? null : cols.get(0); |
| if (col != null) { |
| if (col.getJavaType() != JavaTypes.OBJECT) |
| return col.getJavaType(); |
| if (col.getType() != Types.OTHER) |
| return JavaTypes.getTypeCode(Schemas.getJavaType |
| (col.getType(), col.getSize(), col.getDecimalDigits())); |
| } |
| return JavaTypes.STRING; |
| } |
| |
| @Override |
| protected Object getDiscriminatorValue(ClassMapping cls) { |
| Object val = cls.getDiscriminator().getValue(); |
| return (val == Discriminator.NULL) ? null : val; |
| } |
| |
| @Override |
| protected Class getClass(Object val, JDBCStore store) |
| throws ClassNotFoundException { |
| |
| if(_vals == null) { |
| _writeLock.lock(); |
| try { |
| if(_vals == null) { |
| _vals = constructCache(disc); |
| } |
| } finally { |
| _writeLock.unlock(); |
| } |
| } |
| |
| String className = (val == null) ? null : val.toString(); |
| _readLock.lock(); |
| try { |
| Class<?> clz = _vals.get(className); |
| if (clz != null) |
| return clz; |
| } finally { |
| _readLock.unlock(); |
| } |
| |
| _writeLock.lock(); |
| try { |
| Class<?> clz = _vals.get(className); |
| if (clz != null) |
| return clz; |
| |
| //Rebuild the cache to check for updates |
| _vals = constructCache(disc); |
| |
| //Try get again |
| clz = _vals.get(className); |
| if (clz != null) |
| return clz; |
| throw new ClassNotFoundException(_loc.get("unknown-discrim-value", |
| new Object[]{ className, disc.getClassMapping().getDescribedType(). |
| getName(), new TreeSet<String>(_vals.keySet()) }).getMessage()); |
| } finally { |
| _writeLock.unlock(); |
| } |
| } |
| |
| /** |
| * Build a class cache map from the discriminator |
| */ |
| private static Map<String, Class<?>> constructCache(Discriminator disc) { |
| //Build the cache map |
| ClassMapping cls = disc.getClassMapping(); |
| ClassMapping[] subs = cls.getJoinablePCSubclassMappings(); |
| Map<String, Class<?>> map = new HashMap<String, Class<?>>((int) ((subs.length + 1) * 1.33 + 1)); |
| mapDiscriminatorValue(cls, map); |
| for (int i = 0; i < subs.length; i++) |
| mapDiscriminatorValue(subs[i], map); |
| return map; |
| } |
| |
| /** |
| * Map the stringified version of the discriminator value of the given type. |
| */ |
| private static void mapDiscriminatorValue(ClassMapping cls, Map<String, Class<?>> map) { |
| // possible that some types will never be persisted and therefore |
| // can have no discriminator value |
| Object val = cls.getDiscriminator().getValue(); |
| if (val == null) |
| return; |
| |
| String str = (val == Discriminator.NULL) ? null : val.toString(); |
| Class<?> exist = map.get(str); |
| if (exist != null) |
| throw new MetaDataException(_loc.get("dup-discrim-value", |
| str, exist, cls)); |
| map.put(str, cls.getDescribedType()); |
| } |
| |
| @Override |
| public void map(boolean adapt) { |
| Object val = disc.getMappingInfo().getValue(disc, adapt); |
| if (val == null && !Modifier.isAbstract(disc.getClassMapping(). |
| getDescribedType().getModifiers())) |
| throw new MetaDataException(_loc.get("no-discrim-value", |
| disc.getClassMapping())); |
| |
| // we set the value before mapping to use to calculate the template |
| // column's java type |
| disc.setValue(val); |
| super.map(adapt); |
| } |
| } |