package org.drools.rule;
/*
* Copyright 2005 JBoss Inc
*
* Licensed 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.
*/
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.drools.common.DroolsObjectInputStream;
import org.drools.facttemplates.FactTemplate;
import org.drools.ruleflow.common.core.Process;
import org.drools.util.StringUtils;
/**
* Collection of related <code>Rule</code>s.
*
* @see Rule
*
* @author <a href="mail:bob@werken.com">bob mcwhirter </a>
*
* @version $Id: Package.java,v 1.1 2005/07/26 01:06:31 mproctor Exp $
*/
public class Package
implements
Externalizable {
// ------------------------------------------------------------
// Constants`
// ------------------------------------------------------------
/**
*
*/
private static final long serialVersionUID = 400L;
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** Name of the pkg. */
private String name;
/** Set of all rule-names in this <code>Package</code>. */
private Map rules;
private Set imports;
private List functions;
private Set staticImports;
private Map globals;
private Map factTemplates;
private Map ruleFlows;
private PackageCompilationData packageCompilationData;
/** This is to indicate the the package has no errors during the compilation/building phase */
private boolean valid = true;
/** This will keep a summary error message as to why this package is not valid */
private String errorSummary;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Default constructor - for Externalizable. This should never be used by a user, as it
* will result in an invalid state for the instance.
*/
public Package() {
}
/**
* Construct.
*
* @param name
* The name of this <code>Package</code>.
*/
public Package(final String name) {
this( name,
null );
}
/**
* Construct.
*
* @param name
* The name of this <code>Package</code>.
*/
public Package(final String name,
ClassLoader parentClassLoader) {
this.name = name;
this.imports = new HashSet();
this.staticImports = Collections.EMPTY_SET;
this.rules = new LinkedHashMap();
this.ruleFlows = Collections.EMPTY_MAP;
this.globals = Collections.EMPTY_MAP;
this.factTemplates = Collections.EMPTY_MAP;
this.functions = Collections.EMPTY_LIST;
// This classloader test should only be here for unit testing, too much legacy api to want to change by hand at the moment
if ( parentClassLoader == null ) {
parentClassLoader = Thread.currentThread().getContextClassLoader();
if ( parentClassLoader == null ) {
parentClassLoader = getClass().getClassLoader();
}
}
this.packageCompilationData = new PackageCompilationData( parentClassLoader );
}
/**
* Handles the write serialization of the Package. Patterns in Rules may reference generated data which cannot be serialized by default methods.
* The Package uses PackageCompilationData to hold a reference to the generated bytecode. The generated bytecode must be restored before any Rules.
*
*/
public void writeExternal(final ObjectOutput stream) throws IOException {
stream.writeObject( this.packageCompilationData );
stream.writeObject( this.name );
stream.writeObject( this.imports );
stream.writeObject( this.staticImports );
stream.writeObject( this.functions );
stream.writeObject( this.factTemplates );
stream.writeObject( this.ruleFlows );
stream.writeObject( this.globals );
stream.writeBoolean( this.valid );
// Rules must be restored by an ObjectInputStream that can resolve using a given ClassLoader to handle seaprately by storing as
// a byte[]
final ByteArrayOutputStream bos = new ByteArrayOutputStream();
final ObjectOutput out = new ObjectOutputStream( bos );
out.writeObject( this.rules );
stream.writeObject( bos.toByteArray() );
}
/**
* Handles the read serialization of the Package. Patterns in Rules may reference generated data which cannot be serialized by default methods.
* The Package uses PackageCompilationData to hold a reference to the generated bytecode; which must be restored before any Rules.
* A custom ObjectInputStream, able to resolve classes against the bytecode in the PackageCompilationData, is used to restore the Rules.
*
*/
public void readExternal(final ObjectInput stream) throws IOException,
ClassNotFoundException {
// PackageCompilationData must be restored before Rules as it has the ClassLoader needed to resolve the generated code references in Rules
this.packageCompilationData = (PackageCompilationData) stream.readObject();
this.name = (String) stream.readObject();
this.imports = (Set) stream.readObject();
this.staticImports = (Set) stream.readObject();
this.functions = (List) stream.readObject();
this.factTemplates = (Map) stream.readObject();
this.ruleFlows = (Map) stream.readObject();
this.globals = (Map) stream.readObject();
this.valid = stream.readBoolean();
// Return the rules stored as a byte[]
final byte[] bytes = (byte[]) stream.readObject();
// Use a custom ObjectInputStream that can resolve against a given classLoader
final DroolsObjectInputStream streamWithLoader = new DroolsObjectInputStream( new ByteArrayInputStream( bytes ),
this.packageCompilationData.getClassLoader() );
this.rules = (Map) streamWithLoader.readObject();
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Retrieve the name of this <code>Package</code>.
*
* @return The name of this <code>Package</code>.
*/
public String getName() {
return this.name;
}
public void addImport(final String importEntry) {
this.imports.add( importEntry );
}
public void removeImport(final String importEntry) {
this.imports.remove( importEntry );
}
public Set getImports() {
return this.imports;
}
public void addStaticImport(final String functionImport) {
if ( this.staticImports == Collections.EMPTY_SET ) {
this.staticImports = new HashSet( 2 );
}
this.staticImports.add( functionImport );
}
public void addFunction(final String functionName) {
if ( this.functions == Collections.EMPTY_LIST ) {
this.functions = new ArrayList( 1 );
}
this.functions.add( functionName );
}
public List getFunctions() {
return this.functions;
}
public void removeFunctionImport(final String functionImport) {
this.staticImports.remove( functionImport );
}
public Set getStaticImports() {
return this.staticImports;
}
public void addGlobal(final String identifier,
final Class clazz) {
if ( this.globals == Collections.EMPTY_MAP ) {
this.globals = new HashMap( 1 );
}
this.globals.put( identifier,
clazz );
}
public void removeGlobal(final String identifier) {
this.globals.remove( identifier );
}
public Map getGlobals() {
return this.globals;
}
public PackageCompilationData removeFunction(final String functionName) {
if ( !this.functions.remove( functionName )) {
return null;
}
this.packageCompilationData.remove( this.name + "." + StringUtils.ucFirst( functionName ) );
return this.packageCompilationData;
}
public FactTemplate getFactTemplate(final String name) {
return (FactTemplate) this.factTemplates.get( name );
}
public void addFactTemplate(final FactTemplate factTemplate) {
if ( this.factTemplates == Collections.EMPTY_MAP ) {
this.factTemplates = new HashMap( 1 );
}
this.factTemplates.put( factTemplate.getName(),
factTemplate );
}
/**
* Add a <code>Rule</code> to this <code>Package</code>.
*
* @param rule
* The rule to add.
*
* @throws DuplicateRuleNameException
* If the <code>Rule</code> attempting to be added has the
* same name as another previously added <code>Rule</code>.
* @throws InvalidRuleException
* If the <code>Rule</code> is not valid.
*/
public void addRule(final Rule rule) {
final String name = rule.getName();
this.rules.put( name,
rule );
rule.setLoadOrder( this.rules.size() );
}
/**
* Add a rule flow to this package.
*/
public void addRuleFlow(Process process) {
if ( this.ruleFlows == Collections.EMPTY_MAP ) {
this.ruleFlows = new HashMap();
}
this.ruleFlows.put( process.getId(),
process );
}
/**
* Get the rule flows for this package. The key is the ruleflow id.
* It will be Collections.EMPTY_MAP if none have been added.
*/
public Map getRuleFlows() {
return this.ruleFlows;
}
/**
* Rule flows can be removed by ID.
*/
public void removeRuleFlow(String id) {
if ( !this.ruleFlows.containsKey( id ) ) {
throw new IllegalArgumentException( "The rule flow with id [" + id + "] is not part of this package." );
}
this.ruleFlows.remove( id );
}
public PackageCompilationData removeRule(final Rule rule) {
this.rules.remove( rule.getName() );
final String consequenceName = rule.getConsequence().getClass().getName();
// check for compiled code and remove if present.
if ( this.packageCompilationData.remove( consequenceName ) ) {
removeClasses( rule.getLhs() );
// Now remove the rule class - the name is a subset of the consequence name
this.packageCompilationData.remove( consequenceName.substring( 0,
consequenceName.indexOf( "ConsequenceInvoker" ) ) );
}
return this.packageCompilationData;
}
private void removeClasses(final ConditionalElement ce) {
if ( ce instanceof GroupElement ) {
final GroupElement group = (GroupElement) ce;
for ( final Iterator it = group.getChildren().iterator(); it.hasNext(); ) {
final Object object = it.next();
if ( object instanceof ConditionalElement ) {
removeClasses( (ConditionalElement) object );
} else if ( object instanceof Pattern ) {
removeClasses( (Pattern) object );
}
}
} else if ( ce instanceof EvalCondition ) {
this.packageCompilationData.remove( ((EvalCondition) ce).getEvalExpression().getClass().getName() );
}
}
private void removeClasses(final Pattern pattern) {
for ( final Iterator it = pattern.getConstraints().iterator(); it.hasNext(); ) {
final Object object = it.next();
if ( object instanceof PredicateConstraint ) {
this.packageCompilationData.remove( ((PredicateConstraint) object).getPredicateExpression().getClass().getName() );
} else if ( object instanceof ReturnValueConstraint ) {
this.packageCompilationData.remove( ((ReturnValueConstraint) object).getExpression().getClass().getName() );
}
}
}
/**
* Retrieve a <code>Rule</code> by name.
*
* @param name
* The name of the <code>Rule</code> to retrieve.
*
* @return The named <code>Rule</code>, or <code>null</code> if not
* such <code>Rule</code> has been added to this
* <code>Package</code>.
*/
public Rule getRule(final String name) {
return (Rule) this.rules.get( name );
}
/**
* Retrieve all <code>Rules</code> in this <code>Package</code>.
*
* @return An array of all <code>Rules</code> in this <code>Package</code>.
*/
public Rule[] getRules() {
return (Rule[]) this.rules.values().toArray( new Rule[this.rules.size()] );
}
public PackageCompilationData getPackageCompilationData() {
return this.packageCompilationData;
}
public String toString() {
return "[Package name=" + this.name + "]";
}
/** Once this is called, the package will be marked as invalid */
public void setError(final String summary) {
this.errorSummary = summary;
this.valid = false;
}
/**
* @return true (default) if there are no build/structural problems.
*/
public boolean isValid() {
return this.valid;
}
/** This will throw an exception if the package is not valid */
public void checkValidity() {
if ( !isValid() ) {
throw new InvalidRulePackage( this.getErrorSummary() );
}
}
/**
* This will return the error summary (if any) if the package is invalid.
*/
public String getErrorSummary() {
return this.errorSummary;
}
public boolean equals(final Object object) {
if ( this == object ) {
return true;
}
if ( object == null || !(object instanceof Package) ) {
return false;
}
final Package other = (Package) object;
return (this.name.equals( other.name ));
}
public int hashCode() {
return this.name.hashCode();
}
public void clear() {
this.rules.clear();
this.packageCompilationData.clear();
this.ruleFlows.clear();
this.imports.clear();
this.functions.clear();
this.staticImports.clear();
this.globals.clear();
this.factTemplates.clear();
}
}