| /* |
| * 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.kernel.exps; |
| |
| import java.util.LinkedList; |
| import java.util.ListIterator; |
| import java.util.Objects; |
| |
| import org.apache.openjpa.kernel.Broker; |
| import org.apache.openjpa.kernel.Filters; |
| import org.apache.openjpa.kernel.OpenJPAStateManager; |
| import org.apache.openjpa.kernel.StoreContext; |
| import org.apache.openjpa.meta.ClassMetaData; |
| import org.apache.openjpa.meta.FieldMetaData; |
| import org.apache.openjpa.meta.XMLMetaData; |
| import org.apache.openjpa.util.ImplHelper; |
| |
| /** |
| * A path represents a traversal into fields of a candidate object. |
| * |
| * @author Abe White |
| */ |
| public class CandidatePath |
| extends Val |
| implements Path { |
| |
| |
| private static final long serialVersionUID = 1L; |
| protected LinkedList _actions = null; |
| protected String _correlationVar = null; |
| |
| /** |
| * Traverse into the given field of the current object, and update |
| * the current object to that field value. |
| */ |
| @Override |
| public void get(FieldMetaData field, boolean nullTraversal) { |
| if (_actions == null) |
| _actions = new LinkedList(); |
| _actions.add(new Traversal(field, nullTraversal)); |
| } |
| |
| @Override |
| public Class getType() { |
| if (_actions == null) |
| return getCandidateType(); |
| |
| Object last = _actions.getLast(); |
| if (last instanceof Class) |
| return (Class) last; |
| FieldMetaData fmd = ((Traversal) last).field; |
| return fmd.getDeclaredType(); |
| } |
| |
| protected Class getCandidateType() { |
| ClassMetaData meta = getMetaData(); |
| if (meta == null) |
| return Object.class; |
| return meta.getDescribedType(); |
| } |
| |
| @Override |
| public void setImplicitType(Class type) { |
| } |
| |
| @Override |
| public FieldMetaData last() { |
| if (_actions == null) |
| return null; |
| |
| ListIterator itr = _actions.listIterator(_actions.size()); |
| Object prev; |
| while (itr.hasPrevious()) { |
| prev = itr.previous(); |
| if (prev instanceof Traversal) |
| return ((Traversal) prev).field; |
| } |
| return null; |
| } |
| |
| /** |
| * Cast this path to the given type. |
| */ |
| public void castTo(Class type) { |
| if (_actions == null) |
| _actions = new LinkedList(); |
| _actions.add(type); |
| } |
| |
| @Override |
| protected Object eval(Object candidate, Object orig, |
| StoreContext ctx, Object[] params) { |
| if (_actions == null) |
| return candidate; |
| |
| Object action; |
| OpenJPAStateManager sm; |
| Broker tmpBroker = null; |
| for (Object o : _actions) { |
| action = o; |
| |
| // fail on null value |
| if (candidate == null) { |
| if (action instanceof Traversal |
| && ((Traversal) action).nullTraversal) |
| return null; |
| throw new NullPointerException(); |
| } |
| |
| // check that the cast is valid |
| if (action instanceof Class) { |
| candidate = Filters.convert(candidate, (Class) action); |
| continue; |
| } |
| |
| // make sure we can access the instance; even non-pc vals might |
| // be proxyable |
| sm = null; |
| tmpBroker = null; |
| if (ImplHelper.isManageable(candidate)) |
| sm = (OpenJPAStateManager) (ImplHelper.toPersistenceCapable( |
| candidate, ctx.getConfiguration())). |
| pcGetStateManager(); |
| if (sm == null) { |
| tmpBroker = ctx.getBroker(); |
| tmpBroker.transactional(candidate, false, null); |
| sm = tmpBroker.getStateManager(candidate); |
| } |
| |
| try { |
| // get the specified field value and switch candidate |
| Traversal traversal = (Traversal) action; |
| candidate = sm.fetchField(traversal.field.getIndex(), true); |
| } |
| finally { |
| // transactional does not clear the state, which is |
| // important since tmpCandidate might be also managed by |
| // another broker if it's a proxied non-pc instance |
| if (tmpBroker != null) |
| tmpBroker.nontransactional(sm.getManagedInstance(), null); |
| } |
| } |
| return candidate; |
| } |
| |
| @Override |
| public int hashCode() { |
| return (_actions == null) ? 0 : _actions.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (other == this) |
| return true; |
| if (!(other instanceof CandidatePath)) |
| return false; |
| return Objects.equals(_actions, ((CandidatePath) other)._actions); |
| } |
| |
| /** |
| * Represents a traversal through a field. |
| */ |
| public static class Traversal { |
| |
| public final FieldMetaData field; |
| public final boolean nullTraversal; |
| |
| private Traversal(FieldMetaData field, boolean nullTraversal) { |
| this.field = field; |
| this.nullTraversal = nullTraversal; |
| } |
| |
| @Override |
| public int hashCode() { |
| return field.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (other == this) |
| return true; |
| return ((Traversal) other).field.equals(field); |
| } |
| } |
| |
| @Override |
| public void get(FieldMetaData fmd, XMLMetaData meta) { |
| } |
| |
| @Override |
| public void get(XMLMetaData meta, String name) { |
| } |
| |
| @Override |
| public XMLMetaData getXmlMapping() { |
| return null; |
| } |
| |
| @Override |
| public void setSchemaAlias(String schemaAlias) { |
| } |
| |
| @Override |
| public String getSchemaAlias() { |
| return null; |
| } |
| |
| @Override |
| public void setSubqueryContext(Context conext, String correlationVar) { |
| } |
| |
| @Override |
| public String getCorrelationVar() { |
| return _correlationVar; |
| } |
| } |