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/*
* 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.datacache;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import org.apache.commons.lang.ObjectUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.openjpa.enhance.PCRegistry;
import org.apache.openjpa.kernel.Query;
import org.apache.openjpa.kernel.QueryContext;
import org.apache.openjpa.kernel.StoreContext;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.meta.JavaTypes;
import org.apache.openjpa.meta.MetaDataRepository;
import org.apache.openjpa.util.ImplHelper;
/**
* This class stores information about a particular invocation of
* a query. It contains a reference to the external properties of the
* query that was executed, as well as any parameters used to execute
* that query, with one exception: first-class objects used as
* parameter values are converted to OIDs.
*
* @author Patrick Linskey
*/
public class QueryKey
implements Externalizable {
// initialize the set of unmodifiable classes. This allows us
// to avoid cloning collections that are not modifiable,
// provided that they do not contain mutable objects.
private static Collection s_unmod = new HashSet();
static {
// handle the set types; jdk uses different classes for collection,
// set, and sorted set
TreeSet s = new TreeSet();
s_unmod.add(Collections.unmodifiableCollection(s).getClass());
s_unmod.add(Collections.unmodifiableSet(s).getClass());
s_unmod.add(Collections.unmodifiableSortedSet(s).getClass());
// handle the list types; jdk uses different classes for standard
// and random access lists
List l = new LinkedList();
s_unmod.add(Collections.unmodifiableList(l).getClass());
l = new ArrayList(0);
s_unmod.add(Collections.unmodifiableList(l).getClass());
// handle the constant types
s_unmod.add(Collections.EMPTY_SET.getClass());
s_unmod.add(Collections.EMPTY_LIST.getClass());
}
// caching state; no need to include parameter and variable declarations
// because they are implicit in the filter
private String _candidateClassName;
private boolean _subclasses;
private Set _accessPathClassNames;
private String _query;
private boolean _ignoreChanges;
private Map _params;
private long _rangeStart;
private long _rangeEnd;
// ### pcl: 2 May 2003: should this timeout take into account the
// ### timeouts for classes in the access path of the query?
// ### Currently, it only considers the candidate class and its
// ### subclasses. Note that this value is used to decide whether
// ### or not OIDs should be registered for expiration callbacks
private int _timeout = -1;
/**
* Return a key for the given query, or null if it is not cacheable.
*/
public static QueryKey newInstance(Query q) {
return newInstance(q, (Object[]) null);
}
/**
* Return a key for the given query, or null if it is not cacheable.
*/
public static QueryKey newInstance(Query q, Object[] args) {
// compile to make sure info encoded in query string is available
// via API calls (candidate class, result class, etc)
q.compile();
return newInstance(q, false, args, q.getCandidateType(),
q.hasSubclasses(), q.getStartRange(), q.getEndRange());
}
/**
* Return a key for the given query, or null if it is not cacheable.
*/
public static QueryKey newInstance(Query q, Map args) {
// compile to make sure info encoded in query string is available
// via API calls (candidate class, result class, etc)
q.compile();
return newInstance(q, false, args, q.getCandidateType(),
q.hasSubclasses(), q.getStartRange(), q.getEndRange());
}
/**
* Return a key for the given query, or null if it is not cacheable.
*/
static QueryKey newInstance(QueryContext q, boolean packed, Object[] args,
Class candidate, boolean subs, long startIdx, long endIdx) {
QueryKey key = createKey(q, packed, candidate, subs, startIdx, endIdx);
if (key != null && setParams(key, q, args))
return key;
return null;
}
/**
* Return a key for the given query, or null if it is not cacheable.
*/
static QueryKey newInstance(QueryContext q, boolean packed, Map args,
Class candidate, boolean subs, long startIdx, long endIdx) {
QueryKey key = createKey(q, packed, candidate, subs, startIdx, endIdx);
if (key != null && (args == null || args.isEmpty() ||
setParams(key, q.getStoreContext(), new HashMap(args))))
return key;
return null;
}
/**
* Extract the relevant identifying information from
* q. This includes information such as candidate
* class, query filter, etc.
*/
private static QueryKey createKey(QueryContext q, boolean packed,
Class candidateClass, boolean subclasses, long startIdx, long endIdx) {
if (candidateClass == null)
return null;
// can only cache datastore queries
if (q.getCandidateCollection() != null)
return null;
// no support already-packed results
if (q.getResultType() != null && packed)
return null;
// can't cache non-serializable non-managed complex types
Class[] types = q.getProjectionTypes();
for (int i = 0; i < types.length; i++) {
switch (JavaTypes.getTypeCode(types[i])) {
case JavaTypes.ARRAY:
return null;
case JavaTypes.COLLECTION:
case JavaTypes.MAP:
case JavaTypes.OBJECT:
if (!ImplHelper.isManagedType(
q.getStoreContext().getConfiguration(), types[i]))
return null;
break;
}
}
// we can't cache the query if we don't know which classes are in the
// access path
ClassMetaData[] metas = q.getAccessPathMetaDatas();
if (metas.length == 0)
return null;
Set accessPathClassNames = new HashSet((int) (metas.length * 1.33 + 1));
ClassMetaData meta;
for (int i = 0; i < metas.length; i++) {
// since the class change framework deals with least-derived types,
// record the least-derived access path types
meta = metas[i];
accessPathClassNames.add(meta.getDescribedType().getName());
while (meta.getPCSuperclass() != null) {
meta = meta.getPCSuperclassMetaData();
}
accessPathClassNames.add(meta.getDescribedType().getName());
}
// if any of the types are currently dirty, we can't cache this query
StoreContext ctx = q.getStoreContext();
if (intersects(accessPathClassNames, ctx.getPersistedTypes())
|| intersects(accessPathClassNames, ctx.getUpdatedTypes())
|| intersects(accessPathClassNames, ctx.getDeletedTypes()))
return null;
// calculate the timeout for the key
MetaDataRepository repos = ctx.getConfiguration().
getMetaDataRepositoryInstance();
// won't find metadata for interfaces.
if (candidateClass.isInterface())
return null;
meta = repos.getMetaData(candidateClass, ctx.getClassLoader(), true);
int timeout = meta.getDataCacheTimeout();
if (subclasses) {
metas = meta.getPCSubclassMetaDatas();
int subTimeout;
for (int i = 0; i < metas.length; i++) {
if (metas[i].getDataCache() == null)
return null;
accessPathClassNames.add(metas[i].getDescribedType().getName());
subTimeout = metas[i].getDataCacheTimeout();
if (subTimeout != -1 && subTimeout < timeout)
timeout = subTimeout;
}
}
// tests all passed; cacheable
QueryKey key = new QueryKey();
key._candidateClassName = candidateClass.getName();
key._subclasses = subclasses;
key._accessPathClassNames = accessPathClassNames;
key._timeout = timeout;
key._query = q.getQueryString();
key._ignoreChanges = q.getIgnoreChanges();
key._rangeStart = startIdx;
key._rangeEnd = endIdx;
return key;
}
/**
* Convert an array of arguments into the corresponding parameter
* map, and do any PC to OID conversion necessary.
*/
private static boolean setParams(QueryKey key, QueryContext q,
Object[] args) {
if (args == null || args.length == 0)
return true;
// Create a map for the given parameters, and convert the
// parameter list into a map, using the query's parameter
// declaration to determine ordering etc.
Map types = q.getOrderedParameterTypes();
Map map = new HashMap((int) (types.size() * 1.33 + 1));
int idx = 0;
for (Iterator iter = types.keySet().iterator(); iter.hasNext(); idx++)
map.put(iter.next(), args[idx]);
return setParams(key, q.getStoreContext(), map);
}
/**
* Convert parameters to a form that is cacheable. Mutable params
* will be cloned.
*/
private static boolean setParams(QueryKey key, StoreContext ctx,
Map params) {
if (params == null || params.isEmpty())
return true;
Map.Entry e;
Object v;
for (Iterator iter = params.entrySet().iterator(); iter.hasNext();) {
e = (Map.Entry) iter.next();
v = e.getValue();
if (ImplHelper.isManageable(v)) {
if (!ctx.isPersistent(v) || ctx.isNew(v) || ctx.isDeleted(v))
return false;
e.setValue(ctx.getObjectId(v));
}
if (v instanceof Collection) {
Collection c = (Collection) v;
boolean contentsAreDates = false;
if (c.iterator().hasNext()) {
// this assumes that the collection is homogeneous
Object o = c.iterator().next();
if (ImplHelper.isManageable(o))
return false;
// pcl: 27 Jun 2004: if we grow this logic to
// handle other mutable types that are not
// known to be cloneable, we will have to add
// logic to handle them. This is because we
// can't just cast to Cloneable and invoke
// clone(), as clone() is a protected method
// in Object.
if (o instanceof Date)
contentsAreDates = true;
// if the collection is not a known immutable
// type, or if it contains mutable instances,
// clone it for good measure.
if (contentsAreDates || !s_unmod.contains(c.getClass())) {
// copy the collection
Collection copy;
if (c instanceof SortedSet)
copy = new TreeSet();
else if (c instanceof Set)
copy = new HashSet();
else
copy = new ArrayList(c.size());
if (contentsAreDates) {
// must go through by hand and do the
// copy, since Date is mutable.
for (Iterator itr2 = c.iterator(); itr2.hasNext();)
copy.add(((Date) itr2.next()).clone());
} else
copy.addAll(c);
e.setValue(copy);
}
}
} else if (v instanceof Date)
e.setValue(((Date) v).clone());
}
key._params = params;
return true;
}
/**
* Public constructor for externalization only.
*/
public QueryKey() {
}
/**
* Returns the candidate class name for this query.
*/
public String getCandidateTypeName() {
return _candidateClassName;
}
/**
* Return the amount of time this key is good for.
*/
public int getTimeout() {
return _timeout;
}
/**
* Returns true if modifications to any of the
* classes in changed results in a possible
* invalidation of this query; otherwise returns
* false. Invalidation is possible if one or more of
* the classes in this query key's access path has been changed.
*/
public boolean changeInvalidatesQuery(Collection changed) {
return intersects(_accessPathClassNames, changed);
}
/**
* Whether the given set of least-derived class names intersects with
* the given set of changed classes.
*/
private static boolean intersects(Collection names, Collection changed) {
Class cls;
Class sup;
for (Iterator iter = changed.iterator(); iter.hasNext();) {
cls = (Class) iter.next();
while ((sup = PCRegistry.getPersistentSuperclass(cls)) != null)
cls = sup;
if (names.contains(cls.getName()))
return true;
}
return false;
}
/**
* Determine equality based on identifying information. Keys
* created for queries that specify a candidate collection are
* always not equal.
*/
public boolean equals(Object ob) {
if (this == ob)
return true;
if (ob == null || getClass() != ob.getClass())
return false;
QueryKey other = (QueryKey) ob;
return StringUtils.equals(_candidateClassName,
other._candidateClassName)
&& _subclasses == other._subclasses
&& _ignoreChanges == other._ignoreChanges
&& _rangeStart == other._rangeStart
&& _rangeEnd == other._rangeEnd
&& StringUtils.equals(_query, other._query)
&& ObjectUtils.equals(_params, other._params);
}
/**
* Define a hashing algorithm corresponding to the {@link #equals}
* method defined above.
*/
public int hashCode() {
int code = 37 * 17 + _candidateClassName.hashCode();
if (_query != null)
code = 37 * code + _query.hashCode();
if (_params != null)
code = 37 * code + _params.hashCode();
return code;
}
public String toString() {
StringBuilder buf = new StringBuilder(1024);
buf.append(super.toString()).
append("[query:[").append(_query).append("]").
append(",access path:").append(_accessPathClassNames).
append(",subs:").append(_subclasses).
append(",ignoreChanges:").append(_ignoreChanges).
append(",startRange:").append(_rangeStart).
append(",endRange:").append(_rangeEnd).
append(",timeout:").append(_timeout).
append("]");
return buf.toString();
}
// ---------- Externalizable implementation ----------
public void writeExternal(ObjectOutput out)
throws IOException {
out.writeObject(_candidateClassName);
out.writeBoolean(_subclasses);
out.writeObject(_accessPathClassNames);
out.writeObject(_query);
out.writeBoolean(_ignoreChanges);
out.writeObject(_params);
out.writeLong(_rangeStart);
out.writeLong(_rangeEnd);
out.writeInt(_timeout);
}
public void readExternal(ObjectInput in)
throws IOException, ClassNotFoundException {
_candidateClassName = (String) in.readObject();
_subclasses = in.readBoolean();
_accessPathClassNames = (Set) in.readObject();
_query = (String) in.readObject();
_ignoreChanges = in.readBoolean();
_params = (Map) in.readObject();
_rangeStart = in.readLong();
_rangeEnd = in.readLong ();
_timeout = in.readInt ();
}
/**
* Returns the set of the accessPathClassnames that exists in the query
* @return -- Returns a set of accesspath classnames.
*/
public Set getAcessPathClassNames() {
return this._accessPathClassNames;
}
}
