/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.dqp.internal.process.multisource;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import org.teiid.core.TeiidComponentException;
import org.teiid.query.optimizer.capabilities.CapabilitiesFinder;
import org.teiid.query.optimizer.capabilities.SourceCapabilities;
import org.teiid.query.optimizer.capabilities.SourceCapabilities.Capability;
/**
* A capabilities finder proxy that intercepts capabilities calls for multi-source models
* and hard-codes some capabilities for certain functionality that will not be planned
* correctly for multi-source queries otherwise.
* @since 4.2
*/
public class MultiSourceCapabilitiesFinder implements
CapabilitiesFinder {
private CapabilitiesFinder finder;
private Collection multiSourceModels;
public MultiSourceCapabilitiesFinder(CapabilitiesFinder finder, Collection multiSourceModels) {
this.finder = finder;
this.multiSourceModels = multiSourceModels;
}
public SourceCapabilities findCapabilities(String modelName) throws TeiidComponentException {
SourceCapabilities caps = finder.findCapabilities(modelName);
if(multiSourceModels.contains(modelName)) {
caps = modifyCapabilities(caps);
}
return caps;
}
/**
* Wrapper the existing capabilities to modify a few capabilities
* @param caps Real source capabilities
* @return Modified capabilities to work correctly when planning with multi-source models
* @since 4.2
*/
SourceCapabilities modifyCapabilities(SourceCapabilities caps) {
// Create a dynamic proxy that intercepts just a couple method calls
InvocationHandler handler = new MultiSourceHandler(caps);
return (SourceCapabilities) Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class[] { SourceCapabilities.class }, handler);
}
private static class MultiSourceHandler implements InvocationHandler {
private SourceCapabilities caps;
public MultiSourceHandler(SourceCapabilities caps) {
this.caps = caps;
}
private static final String CAPABILITY_METHOD = "supportsCapability"; //$NON-NLS-1$
private static final Set<Capability> DISALLOWED_CAPABILITIES = new HashSet<Capability>(Arrays.asList(
Capability.QUERY_UNION,
Capability.QUERY_EXCEPT,
Capability.QUERY_INTERSECT,
Capability.QUERY_AGGREGATES_AVG,
Capability.QUERY_AGGREGATES_COUNT,
Capability.QUERY_AGGREGATES_COUNT_STAR,
Capability.QUERY_AGGREGATES_DISTINCT,
Capability.QUERY_AGGREGATES_MAX,
Capability.QUERY_AGGREGATES_MIN,
Capability.QUERY_AGGREGATES_SUM,
Capability.QUERY_GROUP_BY,
Capability.QUERY_HAVING,
Capability.QUERY_ORDERBY,
Capability.QUERY_SELECT_DISTINCT,
Capability.ROW_LIMIT,
Capability.ROW_OFFSET
));
/**
* @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
* @since 4.2
*/
public Object invoke(Object proxy,
Method method,
Object[] args) throws Throwable {
String methodName = method.getName();
if(methodName.equals(CAPABILITY_METHOD)) {
Capability capability = (Capability) args[0];
if(DISALLOWED_CAPABILITIES.contains(capability)) {
return Boolean.FALSE;
}
}
return method.invoke(this.caps, args);
}
}
}