helma/src/helma/objectmodel/db/Relation.java
2006-01-25 16:42:02 +00:00

1313 lines
44 KiB
Java

/*
* Helma License Notice
*
* The contents of this file are subject to the Helma License
* Version 2.0 (the "License"). You may not use this file except in
* compliance with the License. A copy of the License is available at
* http://adele.helma.org/download/helma/license.txt
*
* Copyright 1998-2003 Helma Software. All Rights Reserved.
*
* $RCSfile$
* $Author$
* $Revision$
* $Date$
*/
package helma.objectmodel.db;
import helma.framework.core.Application;
import helma.objectmodel.INode;
import helma.objectmodel.IProperty;
import helma.util.StringUtils;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Enumeration;
import java.util.Vector;
/**
* This describes how a property of a persistent Object is stored in a
* relational database table. This can be either a scalar property (string, date, number etc.)
* or a reference to one or more other objects.
*/
public final class Relation {
// these constants define different type of property-to-db-mappings
// there is an error in the description of this relation
public final static int INVALID = -1;
// a mapping of a non-object, scalar type
public final static int PRIMITIVE = 0;
// a 1-to-1 relation, i.e. a field in the table is a foreign key to another object
public final static int REFERENCE = 1;
// a 1-to-many relation, a field in another table points to objects of this type
public final static int COLLECTION = 2;
// a 1-to-1 reference with multiple or otherwise not-trivial constraints
// this is managed differently than REFERENCE, hence the separate type.
public final static int COMPLEX_REFERENCE = 3;
// constraints linked together by OR or AND if applicable?
public final static String AND = " AND ";
public final static String OR = " OR ";
public final static String XOR = " XOR ";
private String logicalOperator = AND;
// prefix to use for symbolic names of joined tables. The name is composed
// from this prefix and the name of the property we're doing the join for
final static String JOIN_PREFIX = "JOIN_";
// direct mapping is a very powerful feature:
// objects of some types can be directly accessed
// by one of their properties/db fields.
// public final static int DIRECT = 3;
// the DbMapping of the type we come from
DbMapping ownType;
// the DbMapping of the prototype we link to, unless this is a "primitive" (non-object) relation
DbMapping otherType;
// the column type, as defined in java.sql.Types
int columnType;
// if this relation defines a virtual node, we need to provide a DbMapping for these virtual nodes
DbMapping virtualMapping;
String propName;
String columnName;
int reftype;
Constraint[] constraints;
boolean virtual;
boolean readonly;
boolean aggressiveLoading;
boolean aggressiveCaching;
boolean isPrivate = false;
boolean referencesPrimaryKey = false;
String accessName; // db column used to access objects through this relation
String order;
String groupbyOrder;
String groupby;
String prototype;
String groupbyPrototype;
String filter;
private String additionalTables;
private boolean additionalTablesJoined = false;
String queryHints;
Vector filterFragments;
Vector filterPropertyRefs;
int maxSize = 0;
/**
* This constructor makes a copy of an existing relation. Not all fields are copied, just those
* which are needed in groupby- and virtual nodes defined by this relation.
*/
private Relation(Relation rel) {
// Note: prototype, groupby, groupbyPrototype and groupbyOrder aren't copied here.
// these are set by the individual get*Relation() methods as appropriate.
this.ownType = rel.ownType;
this.otherType = rel.otherType;
this.propName = rel.propName;
this.columnName = rel.columnName;
this.reftype = rel.reftype;
this.order = rel.order;
this.filter = rel.filter;
this.filterFragments = rel.filterFragments;
this.filterPropertyRefs = rel.filterPropertyRefs;
this.additionalTables = rel.additionalTables;
this.additionalTablesJoined = rel.additionalTablesJoined;
this.queryHints = rel.queryHints;
this.maxSize = rel.maxSize;
this.constraints = rel.constraints;
this.accessName = rel.accessName;
this.maxSize = rel.maxSize;
this.logicalOperator = rel.logicalOperator;
this.aggressiveLoading = rel.aggressiveLoading;
this.aggressiveCaching = rel.aggressiveCaching;
}
/**
* Reads a relation entry from a line in a properties file.
*/
public Relation(String propName, DbMapping ownType) {
this.ownType = ownType;
this.propName = propName;
otherType = null;
}
////////////////////////////////////////////////////////////////////////////////////////////
// parse methods for new file format
////////////////////////////////////////////////////////////////////////////////////////////
public void update(String desc, Properties props) {
Application app = ownType.getApplication();
if ((desc == null) || "".equals(desc.trim())) {
if (propName != null) {
reftype = PRIMITIVE;
columnName = propName;
} else {
reftype = INVALID;
columnName = propName;
}
} else {
desc = desc.trim();
int open = desc.indexOf("(");
int close = desc.indexOf(")");
if ((open > -1) && (close > open)) {
String ref = desc.substring(0, open).trim();
String proto = desc.substring(open + 1, close).trim();
if ("collection".equalsIgnoreCase(ref)) {
virtual = !"_children".equalsIgnoreCase(propName);
reftype = COLLECTION;
} else if ("mountpoint".equalsIgnoreCase(ref)) {
virtual = true;
reftype = COLLECTION;
prototype = proto;
} else if ("object".equalsIgnoreCase(ref)) {
virtual = false;
if (reftype != COMPLEX_REFERENCE) {
reftype = REFERENCE;
}
} else {
throw new RuntimeException("Invalid property Mapping: " + desc);
}
otherType = app.getDbMapping(proto);
if (otherType == null) {
throw new RuntimeException("DbMapping for " + proto +
" not found from " + ownType.getTypeName());
}
// make sure the type we're referring to is up to date!
if (otherType.needsUpdate()) {
otherType.update();
}
} else {
virtual = false;
columnName = desc;
reftype = PRIMITIVE;
}
}
readonly = "true".equalsIgnoreCase(props.getProperty(propName + ".readonly"));
isPrivate = "true".equalsIgnoreCase(props.getProperty(propName + ".private"));
// the following options only apply to object and collection relations
if ((reftype != PRIMITIVE) && (reftype != INVALID)) {
Vector newConstraints = new Vector();
parseOptions(newConstraints, props);
constraints = new Constraint[newConstraints.size()];
newConstraints.copyInto(constraints);
if (reftype == REFERENCE || reftype == COMPLEX_REFERENCE) {
if (constraints.length == 0) {
referencesPrimaryKey = true;
} else {
boolean rprim = false;
for (int i=0; i<constraints.length; i++) {
if (constraints[0].foreignKeyIsPrimary()) {
rprim = true;
}
}
referencesPrimaryKey = rprim;
}
// check if this is a non-trivial reference
if (constraints.length > 0 && !usesPrimaryKey()) {
reftype = COMPLEX_REFERENCE;
} else {
reftype = REFERENCE;
}
}
if (reftype == COLLECTION) {
referencesPrimaryKey = (accessName == null) ||
accessName.equalsIgnoreCase(otherType.getIDField());
}
// if DbMapping for virtual nodes has already been created,
// update its subnode relation.
// FIXME: needs to be synchronized?
if (virtualMapping != null) {
virtualMapping.lastTypeChange = ownType.lastTypeChange;
virtualMapping.subRelation = getVirtualSubnodeRelation();
virtualMapping.propRelation = getVirtualPropertyRelation();
}
} else {
referencesPrimaryKey = false;
}
}
protected void parseOptions(Vector cnst, Properties props) {
String loading = props.getProperty(propName + ".loadmode");
aggressiveLoading = (loading != null) &&
"aggressive".equalsIgnoreCase(loading.trim());
String caching = props.getProperty(propName + ".cachemode");
aggressiveCaching = (caching != null) &&
"aggressive".equalsIgnoreCase(caching.trim());
// get order property
order = props.getProperty(propName + ".order");
if ((order != null) && (order.trim().length() == 0)) {
order = null;
}
// get additional filter property
filter = props.getProperty(propName + ".filter");
if (filter != null) {
if (filter.trim().length() == 0) {
filter = null;
filterFragments = filterPropertyRefs = null;
} else {
// parenthesise filter
Vector fragments = new Vector();
Vector propertyRefs = new Vector();
parsePropertyString(filter, fragments, propertyRefs);
// if no references where found, just use the filter string
// otherwise use the filter fragments and proeprty refs instead
if (propertyRefs.size() > 0) {
filterFragments = fragments;
filterPropertyRefs = propertyRefs;
} else {
filterFragments = filterPropertyRefs = null;
}
}
}
// get additional tables
additionalTables = props.getProperty(propName + ".filter.additionalTables");
if (additionalTables != null) {
if (additionalTables.trim().length() == 0) {
additionalTables = null;
} else {
String ucTables = additionalTables.toUpperCase();
// create dependencies implied by additional tables
DbSource dbsource = otherType.getDbSource();
if (dbsource != null) {
String[] tables = StringUtils.split(ucTables, ", ");
for (int i=0; i<tables.length; i++) {
// Skip some join-related keyworks we might encounter here
if ("AS".equals(tables[i]) || "ON".equals(tables[i])) {
continue;
}
DbMapping dbmap = dbsource.getDbMapping(tables[i]);
if (dbmap != null) {
dbmap.addDependency(otherType);
}
}
}
// see wether the JOIN syntax is used. look for " join " with whitespaces on both sides
// and for "join " at the beginning:
additionalTablesJoined = (ucTables.indexOf(" JOIN ") != -1 ||
ucTables.startsWith("STRAIGHT_JOIN ") || ucTables.startsWith("JOIN "));
}
}
// get query hints
queryHints = props.getProperty(propName + ".hints");
// get max size of collection
String max = props.getProperty(propName + ".maxSize");
if (max != null) {
try {
maxSize = Integer.parseInt(max);
} catch (NumberFormatException nfe) {
maxSize = 0;
}
} else {
maxSize = 0;
}
// get group by property
groupby = props.getProperty(propName + ".group");
if ((groupby != null) && (groupby.trim().length() == 0)) {
groupby = null;
}
if (groupby != null) {
groupbyOrder = props.getProperty(propName + ".group.order");
if ((groupbyOrder != null) && (groupbyOrder.trim().length() == 0)) {
groupbyOrder = null;
}
groupbyPrototype = props.getProperty(propName + ".group.prototype");
if ((groupbyPrototype != null) && (groupbyPrototype.trim().length() == 0)) {
groupbyPrototype = null;
}
// aggressive loading and caching is not supported for groupby-nodes
// aggressiveLoading = aggressiveCaching = false;
}
// check if subnode condition should be applied for property relations
accessName = props.getProperty(propName + ".accessname");
// parse contstraints
String local = props.getProperty(propName + ".local");
String foreign = props.getProperty(propName + ".foreign");
if ((local != null) && (foreign != null)) {
cnst.addElement(new Constraint(local, foreign, false));
columnName = local;
}
// parse additional contstraints from *.1 to *.9
for (int i=1; i<10; i++) {
local = props.getProperty(propName + ".local."+i);
foreign = props.getProperty(propName + ".foreign."+i);
if ((local != null) && (foreign != null)) {
cnst.addElement(new Constraint(local, foreign, false));
}
}
// parse constraints logic
if (cnst.size() > 1) {
String logic = props.getProperty(propName + ".logicalOperator");
if ("and".equalsIgnoreCase(logic)) {
logicalOperator = AND;
} else if ("or".equalsIgnoreCase(logic)) {
logicalOperator = OR;
} else if ("xor".equalsIgnoreCase(logic)) {
logicalOperator = XOR;
} else {
logicalOperator = AND;
}
} else {
logicalOperator = AND;
}
}
///////////////////////////////////////////////////////////////////////////////////////////
/**
* Does this relation describe a virtual (collection) node?
*/
public boolean isVirtual() {
return virtual;
}
/**
* Return the target type of this relation, or null if this is a primitive mapping.
*/
public DbMapping getTargetType() {
return otherType;
}
/**
* Get the reference type of this relation.
*/
public int getRefType() {
return reftype;
}
/**
* Tell if this relation represents a primitive (scalar) value mapping.
*/
public boolean isPrimitive() {
return reftype == PRIMITIVE;
}
/**
* Returns true if this Relation describes an object reference property
*/
public boolean isReference() {
return reftype == REFERENCE;
}
/**
* Returns true if this Relation describes a collection.
* <b>NOTE:</b> this will return true both for collection objects
* (aka virtual nodes) and direct child object relations, so
* isVirtual() should be used to identify relations that define
* <i>collection properties</i>!
*/
public boolean isCollection() {
return reftype == COLLECTION;
}
/**
* Returns true if this Relation describes a complex object reference property
*/
public boolean isComplexReference() {
return reftype == COMPLEX_REFERENCE;
}
/**
* Tell wether the property described by this relation is to be handled as private, i.e.
* a change on it should not result in any changed object/collection relations.
*/
public boolean isPrivate() {
return isPrivate;
}
/**
* Check whether aggressive loading is set for this relation
*/
public boolean loadAggressively() {
return aggressiveLoading;
}
/**
* Returns the number of constraints for this relation.
*/
public int countConstraints() {
if (constraints == null)
return 0;
return constraints.length;
}
/**
* Returns true if the object represented by this Relation has to be
* created on demand at runtime by the NodeManager. This is true for:
*
* - collection (aka virtual) nodes
* - nodes accessed via accessname
* - group nodes
* - complex reference nodes
*/
public boolean createOnDemand() {
if (otherType == null) {
return false;
}
return virtual ||
(otherType.isRelational() && accessName != null) ||
(groupby != null) || isComplexReference();
}
/**
* Returns true if the object represented by this Relation has to be
* persisted in the internal db in order to be functional. This is true if
* the subnodes contained in this collection are stored in the embedded
* database. In this case, the collection itself must also be an ordinary
* object stored in the db, since a virtual collection would lose its
* its content after restarts.
*/
public boolean needsPersistence() {
if (!virtual) {
// ordinary object references always need to be persisted
return true;
}
// collections/mountpoints need to be persisted if the
// child object type is non-relational.
if (prototype == null) {
return !otherType.isRelational();
}
DbMapping sub = otherType.getSubnodeMapping();
return (sub != null) && !sub.isRelational();
}
/**
* Return the prototype to be used for object reached by this relation
*/
public String getPrototype() {
return prototype;
}
/**
* Return the name of the local property this relation is defined for
*/
public String getPropName() {
return propName;
}
/**
*
*
* @param ct ...
*/
public void setColumnType(int ct) {
columnType = ct;
}
/**
*
*
* @return ...
*/
public int getColumnType() {
return columnType;
}
/**
* Get the group for a collection relation, if defined.
*
* @return the name of the column used to group child objects, if any.
*/
public String getGroup() {
return groupby;
}
/**
* Add a constraint to the current list of constraints
*/
protected void addConstraint(Constraint c) {
if (constraints == null) {
constraints = new Constraint[1];
constraints[0] = c;
} else {
Constraint[] nc = new Constraint[constraints.length + 1];
System.arraycopy(constraints, 0, nc, 0, constraints.length);
nc[nc.length - 1] = c;
constraints = nc;
}
}
/**
*
*
* @return true if the foreign key used for this relation is the
* other object's primary key.
*/
public boolean usesPrimaryKey() {
return referencesPrimaryKey;
}
/**
*
*
* @return ...
*/
public boolean hasAccessName() {
return accessName != null;
}
/**
*
*
* @return ...
*/
public String getAccessName() {
return accessName;
}
/**
*
*
* @return ...
*/
public Relation getSubnodeRelation() {
// return subnoderelation;
return null;
}
/**
* Return the local field name for updates.
*/
public String getDbField() {
return columnName;
}
/**
* This is taken from org.apache.tools.ant ProjectHelper.java
* distributed under the Apache Software License, Version 1.1
*
* Parses a string containing <code>${xxx}</code> style property
* references into two lists. The first list is a collection
* of text fragments, while the other is a set of string property names.
* <code>null</code> entries in the first list indicate a property
* reference from the second list.
*
* @param value Text to parse. Must not be <code>null</code>.
* @param fragments List to add text fragments to.
* Must not be <code>null</code>.
* @param propertyRefs List to add property names to.
* Must not be <code>null</code>.
*/
protected void parsePropertyString(String value, Vector fragments, Vector propertyRefs) {
int prev = 0;
int pos;
//search for the next instance of $ from the 'prev' position
while ((pos = value.indexOf("$", prev)) >= 0) {
//if there was any text before this, add it as a fragment
//TODO, this check could be modified to go if pos>prev;
//seems like this current version could stick empty strings
//into the list
if (pos > 0) {
fragments.addElement(value.substring(prev, pos));
}
//if we are at the end of the string, we tack on a $
//then move past it
if (pos == (value.length() - 1)) {
fragments.addElement("$");
prev = pos + 1;
} else if (value.charAt(pos + 1) != '{') {
//peek ahead to see if the next char is a property or not
//not a property: insert the char as a literal
/*
fragments.addElement(value.substring(pos + 1, pos + 2));
prev = pos + 2;
*/
if (value.charAt(pos + 1) == '$') {
//backwards compatibility two $ map to one mode
fragments.addElement("$");
prev = pos + 2;
} else {
//new behaviour: $X maps to $X for all values of X!='$'
fragments.addElement(value.substring(pos, pos + 2));
prev = pos + 2;
}
} else {
//property found, extract its name or bail on a typo
int endName = value.indexOf('}', pos);
if (endName < 0) {
throw new RuntimeException("Syntax error in property: "
+ value);
}
String propertyName = value.substring(pos + 2, endName);
fragments.addElement(null);
propertyRefs.addElement(propertyName);
prev = endName + 1;
}
}
//no more $ signs found
//if there is any tail to the file, append it
if (prev < value.length()) {
fragments.addElement(value.substring(prev));
}
}
/**
* get a DbMapping to use for virtual aka collection nodes.
*/
public DbMapping getVirtualMapping() {
// return null unless this relation describes a virtual/collection node.
if (!virtual) {
return null;
}
// if the collection node is prototyped, return the app's DbMapping
// for that prototype
if (prototype != null) {
return otherType;
}
// create a synthetic DbMapping that describes how to fetch the
// collection's child objects.
if (virtualMapping == null) {
virtualMapping = new DbMapping(ownType.app);
virtualMapping.subRelation = getVirtualSubnodeRelation();
virtualMapping.propRelation = getVirtualPropertyRelation();
}
return virtualMapping;
}
/**
* Return a Relation that defines the subnodes of a virtual node.
*/
Relation getVirtualSubnodeRelation() {
if (!virtual) {
throw new RuntimeException("getVirtualSubnodeRelation called on non-virtual relation");
}
Relation vr = new Relation(this);
vr.groupby = groupby;
vr.groupbyOrder = groupbyOrder;
vr.groupbyPrototype = groupbyPrototype;
return vr;
}
/**
* Return a Relation that defines the properties of a virtual node.
*/
Relation getVirtualPropertyRelation() {
if (!virtual) {
throw new RuntimeException("getVirtualPropertyRelation called on non-virtual relation");
}
Relation vr = new Relation(this);
vr.groupby = groupby;
vr.groupbyOrder = groupbyOrder;
vr.groupbyPrototype = groupbyPrototype;
return vr;
}
/**
* Return a Relation that defines the subnodes of a group-by node.
*/
Relation getGroupbySubnodeRelation() {
if (groupby == null) {
throw new RuntimeException("getGroupbySubnodeRelation called on non-group-by relation");
}
Relation vr = new Relation(this);
vr.prototype = groupbyPrototype;
vr.addConstraint(new Constraint(null, groupby, true));
return vr;
}
/**
* Return a Relation that defines the properties of a group-by node.
*/
Relation getGroupbyPropertyRelation() {
if (groupby == null) {
throw new RuntimeException("getGroupbyPropertyRelation called on non-group-by relation");
}
Relation vr = new Relation(this);
vr.prototype = groupbyPrototype;
vr.addConstraint(new Constraint(null, groupby, true));
return vr;
}
/**
* Build the second half of an SQL select statement according to this relation
* and a local object.
*/
public String buildQuery(INode home, INode nonvirtual, String kstr, String pre,
boolean useOrder) throws SQLException {
StringBuffer q = new StringBuffer();
String prefix = pre;
if (kstr != null && !isComplexReference()) {
q.append(prefix);
String accessColumn = (accessName == null) ? otherType.getIDField() : accessName;
if (accessColumn.indexOf('(') == -1 && accessColumn.indexOf('.') == -1) {
q.append(otherType.getTableName());
q.append(".");
}
q.append(accessColumn);
q.append(" = ");
// check if column is string type and value needs to be quoted
if (otherType.needsQuotes(accessColumn)) {
q.append("'");
q.append(escape(kstr));
q.append("'");
} else {
q.append(escape(kstr));
}
prefix = " AND ";
}
// render the constraints and filter
renderConstraints(q, home, nonvirtual, prefix);
// add joined fetch constraints
ownType.addJoinConstraints(q, prefix);
// add group and order clauses
if (groupby != null) {
q.append(" GROUP BY ").append(groupby);
if (useOrder && (groupbyOrder != null)) {
q.append(" ORDER BY ").append(groupbyOrder);
}
} else if (useOrder && (order != null)) {
q.append(" ORDER BY ").append(order);
}
return q.toString();
}
protected void appendAdditionalTables(StringBuffer q) {
if (additionalTables != null) {
q.append(additionalTablesJoined ? ' ' : ',');
q.append(additionalTables);
}
}
/**
* Build the filter.
*/
protected void appendFilter(StringBuffer q, INode nonvirtual, String prefix) {
q.append(prefix);
q.append('(');
if (filterFragments == null) {
q.append(filter);
} else {
Enumeration i = filterFragments.elements();
Enumeration j = filterPropertyRefs.elements();
while (i.hasMoreElements()) {
String fragment = (String) i.nextElement();
if (fragment == null) {
// begin column version
String columnName = (String) j.nextElement();
Object value = null;
if (columnName != null) {
DbMapping dbmap = nonvirtual.getDbMapping();
String propertyName = dbmap.columnNameToProperty(columnName);
if (propertyName != null) {
IProperty property = nonvirtual.get(propertyName);
if (property != null) {
value = property.getStringValue();
}
}
if (value == null) {
if (columnName.equals(dbmap.getIDField())) {
value = nonvirtual.getID();
} else if (columnName.equals(dbmap.getNameField())) {
value = nonvirtual.getName();
} else if (columnName.equals(dbmap.getPrototypeField())) {
value = nonvirtual.getPrototype();
}
}
}
// end column version
if (value != null) {
q.append(escape(value.toString()));
} else {
q.append("NULL");
}
} else {
q.append(fragment);
}
}
}
q.append(')');
}
/**
* Render contraints and filter conditions to an SQL query string buffer
*
* @param q the query string
* @param home our home node
* @param nonvirtual our non-virtual home node
* @param prefix the prefix to use to append to the existing query (e.g. " AND ")
*
* @throws SQLException ...
*/
public void renderConstraints(StringBuffer q, INode home,
INode nonvirtual, String prefix)
throws SQLException {
if (constraints.length > 1 && logicalOperator != AND) {
q.append(prefix);
q.append("(");
prefix = "";
}
for (int i = 0; i < constraints.length; i++) {
q.append(prefix);
constraints[i].addToQuery(q, home, nonvirtual);
prefix = logicalOperator;
}
if (constraints.length > 1 && logicalOperator != AND) {
q.append(")");
prefix = " AND ";
}
if (filter != null) {
appendFilter(q, nonvirtual, prefix);
}
}
/**
* Render the constraints for this relation for use within
* a left outer join select statement for the base object.
*
* @param select the string buffer to write to
* @param isOracle create Oracle pre-9 style left outer join
*/
public void renderJoinConstraints(StringBuffer select, boolean isOracle) {
for (int i = 0; i < constraints.length; i++) {
select.append(ownType.getTableName());
select.append(".");
select.append(constraints[i].localName);
select.append(" = ");
select.append(JOIN_PREFIX);
select.append(propName);
select.append(".");
select.append(constraints[i].foreignName);
if (isOracle) {
// create old oracle style join - see
// http://www.praetoriate.com/oracle_tips_outer_joins.htm
select.append("(+)");
}
if (i == constraints.length-1) {
select.append(" ");
} else {
select.append(" AND ");
}
}
}
/**
* Get the order section to use for this relation
*/
public String getOrder() {
if (groupby != null) {
return groupbyOrder;
} else {
return order;
}
}
/**
* Tell wether the property described by this relation is to be handled
* as readonly/write protected.
*/
public boolean isReadonly() {
return readonly;
}
/**
* Check if the child node fullfills the constraints defined by this relation.
* FIXME: This always returns false if the relation has a filter value set,
* since we can't determine if the filter constraints are met without
* querying the database.
*
* @param parent the parent object - may be a virtual or group node
* @param child the child object
* @return true if all constraints are met
*/
public boolean checkConstraints(Node parent, Node child) {
// problem: if a filter property is defined for this relation,
// i.e. a piece of static SQL-where clause, we'd have to evaluate it
// in order to check the constraints. Because of this, if a filter
// is defined, we return false as soon as the modified-time is greater
// than the create-time of the child, i.e. if the child node has been
// modified since it was first fetched from the db.
if (filter != null && child.lastModified() > child.created()) {
return false;
}
// counter for constraints and satisfied constraints
int count = 0;
int satisfied = 0;
INode nonvirtual = parent.getNonVirtualParent();
for (int i = 0; i < constraints.length; i++) {
String propname = constraints[i].foreignProperty();
if (propname != null) {
INode home = constraints[i].isGroupby ? parent
: nonvirtual;
String value = null;
if (constraints[i].localKeyIsPrimary(home.getDbMapping())) {
value = home.getID();
} else if (ownType.isRelational()) {
value = home.getString(constraints[i].localProperty());
} else {
value = home.getString(constraints[i].localName);
}
count++;
if (value != null && value.equals(child.getString(propname))) {
satisfied++;
}
}
}
// check if enough constraints are met depending on logical operator
if (logicalOperator == OR) {
return satisfied > 0;
} else if (logicalOperator == XOR) {
return satisfied == 1;
} else {
return satisfied == count;
}
}
/**
* Make sure that the child node fullfills the constraints defined by this relation by setting the
* appropriate properties
*/
public void setConstraints(Node parent, Node child) {
// if logical operator is OR or XOR we just return because we
// wouldn't know what to do anyway
if (logicalOperator != AND) {
return;
}
Node home = parent.getNonVirtualParent();
for (int i = 0; i < constraints.length; i++) {
// don't set groupby constraints since we don't know if the
// parent node is the base node or a group node
if (constraints[i].isGroupby) {
continue;
}
// check if we update the local or the other object, depending on
// whether the primary key of either side is used.
if (constraints[i].foreignKeyIsPrimary()) {
String localProp = constraints[i].localProperty();
if (localProp == null) {
System.err.println ("Error: column "+constraints[i].localName+
" must be mapped in order to be used as constraint in "+
Relation.this);
} else {
home.setString(localProp, child.getID());
}
continue;
}
Relation crel = otherType.columnNameToRelation(constraints[i].foreignName);
if (crel != null) {
// INode home = constraints[i].isGroupby ? parent : nonVirtual;
if (constraints[i].localKeyIsPrimary(home.getDbMapping())) {
// only set node if property in child object is defined as reference.
if (crel.reftype == REFERENCE) {
INode currentValue = child.getNode(crel.propName);
// we set the backwards reference iff the reference is currently unset, if
// is set to a transient object, or if the new target is not transient. This
// prevents us from overwriting a persistent refererence with a transient one,
// which would most probably not be what we want.
if ((currentValue == null) ||
((currentValue != home) &&
((currentValue.getState() == Node.TRANSIENT) ||
(home.getState() != Node.TRANSIENT)))) try {
child.setNode(crel.propName, home);
} catch (Exception ignore) {
// in some cases, getNonVirtualParent() doesn't work
// correctly for transient nodes, so this may fail.
}
} else if (crel.reftype == PRIMITIVE) {
child.setString(crel.propName, home.getID());
}
} else if (crel.reftype == PRIMITIVE) {
Property prop = null;
if (ownType.isRelational()) {
prop = home.getProperty(constraints[i].localProperty());
} else {
prop = home.getProperty(constraints[i].localName);
}
if (prop != null) {
child.set(crel.propName, prop.getValue(), prop.getType());
}
}
}
}
}
/**
* Unset the constraints that link two objects together.
*/
public void unsetConstraints(Node parent, INode child) {
Node home = parent.getNonVirtualParent();
for (int i = 0; i < constraints.length; i++) {
// don't set groupby constraints since we don't know if the
// parent node is the base node or a group node
if (constraints[i].isGroupby) {
continue;
}
// check if we update the local or the other object, depending on
// whether the primary key of either side is used.
if (constraints[i].foreignKeyIsPrimary()) {
String localProp = constraints[i].localProperty();
if (localProp != null) {
home.setString(localProp, null);
}
continue;
}
Relation crel = otherType.columnNameToRelation(constraints[i].foreignName);
if (crel != null) {
// INode home = constraints[i].isGroupby ? parent : nonVirtual;
if (constraints[i].localKeyIsPrimary(home.getDbMapping())) {
// only set node if property in child object is defined as reference.
if (crel.reftype == REFERENCE) {
INode currentValue = child.getNode(crel.propName);
if ((currentValue == home)) {
child.setString(crel.propName, null);
}
} else if (crel.reftype == PRIMITIVE) {
child.setString(crel.propName, null);
}
} else if (crel.reftype == PRIMITIVE) {
Property prop = null;
if (ownType.isRelational()) {
prop = home.getProperty(constraints[i].localProperty());
} else {
prop = home.getProperty(constraints[i].localName);
}
if (prop != null) {
child.setString(crel.propName, null);
}
}
}
}
}
/**
* Returns a map containing the key/value pairs for a specific Node
*/
public Map getKeyParts(INode home) {
Map map = new HashMap();
for (int i=0; i<constraints.length; i++) {
if (ownType.getIDField().equals(constraints[i].localName)) {
map.put(constraints[i].foreignName, home.getID());
} else {
map.put(constraints[i].foreignName, home.getString(constraints[i].localProperty()));
}
}
return map;
}
// a utility method to escape single quotes
String escape(String str) {
if (str == null) {
return null;
}
if (str.indexOf("'") < 0) {
return str;
}
int l = str.length();
StringBuffer sbuf = new StringBuffer(l + 10);
for (int i = 0; i < l; i++) {
char c = str.charAt(i);
if (c == '\'') {
sbuf.append('\'');
}
sbuf.append(c);
}
return sbuf.toString();
}
/**
*
*
* @return ...
*/
public String toString() {
String c = "";
String spacer = "";
if (constraints != null) {
c = " constraints: ";
for (int i = 0; i < constraints.length; i++) {
c += spacer;
c += constraints[i].toString();
spacer = ", ";
}
}
String target = otherType == null ? columnName : otherType.toString();
return "Relation " + ownType+"."+propName + " -> " + target + c;
}
/**
* The Constraint class represents a part of the where clause in the query used to
* establish a relation between database mapped objects.
*/
class Constraint {
String localName;
String foreignName;
boolean isGroupby;
Constraint(String local, String foreign, boolean groupby) {
localName = local;
foreignName = foreign;
isGroupby = groupby;
}
public void addToQuery(StringBuffer q, INode home, INode nonvirtual)
throws SQLException {
String local = null;
INode ref = isGroupby ? home : nonvirtual;
if ((localName == null) ||
localName.equalsIgnoreCase(ref.getDbMapping().getIDField())) {
local = ref.getID();
} else {
String homeprop = ownType.columnNameToProperty(localName);
local = ref.getString(homeprop);
}
if (foreignName.indexOf('(') == -1 && foreignName.indexOf('.') == -1) {
q.append(otherType.getTableName());
q.append(".");
}
q.append(foreignName);
q.append(" = ");
if (otherType.needsQuotes(foreignName)) {
q.append("'");
q.append(escape(local));
q.append("'");
} else {
q.append(escape(local));
}
}
public boolean foreignKeyIsPrimary() {
return (foreignName == null) ||
foreignName.equalsIgnoreCase(otherType.getIDField());
}
public boolean localKeyIsPrimary(DbMapping homeMapping) {
return (homeMapping == null) || (localName == null) ||
localName.equalsIgnoreCase(homeMapping.getIDField());
}
public String foreignProperty() {
return otherType.columnNameToProperty(foreignName);
}
public String localProperty() {
return ownType.columnNameToProperty(localName);
}
public String toString() {
return localName + "=" + otherType.getTypeName() + "." + foreignName;
}
}
}