/*
*
* 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.flex.compiler.problems.collections;
import org.apache.flex.compiler.clients.problems.IProblemFilter;
import org.apache.flex.compiler.problems.ICompilerProblem;
/**
* A CompositeProblemFilter combines one more more filters
* and a boolean operation to produce a new filter.
*/
public class CompositeProblemFilter implements IProblemFilter
{
/** Boolean operator to apply to operand filters */
public enum CompositionOperator {
And,
Or,
Not,
};
@Override
public boolean accept(ICompilerProblem problem)
{
switch ( this.operator )
{
case And:
return left.accept(problem) && right.accept(problem);
case Or:
return left.accept(problem) || right.accept(problem);
case Not:
return ! (left.accept(problem) );
}
assert(false): "Uncovered composition case " + this.operator;
return false;
}
/**
* Construct a CompositeProblemFilter. Only this class' factory methods
* can construct a CompositeProblemFilter.
*/
private CompositeProblemFilter(IProblemFilter left, IProblemFilter right, CompositionOperator operator)
{
this.left = left;
this.right = right;
this.operator = operator;
assert(left != null);
if ( operator == CompositionOperator.Not )
assert right == null;
else
assert right != null;
}
/** left-hand (or only) filter, tested first. */
private IProblemFilter left;
/** right-hand (or missing) filter, tested last or not at all. */
private IProblemFilter right;
/** The operator that determines how this filter works. */
private CompositionOperator operator;
/**
* Construct a composite filter that ands two filters' decisions to accept.
*/
public static IProblemFilter and(IProblemFilter left, IProblemFilter right)
{
return new CompositeProblemFilter(left, right, CompositionOperator.And);
}
/**
* Construct a composite filter that ors two filters' decisions to accept.
*/
public static IProblemFilter or(IProblemFilter left, IProblemFilter right)
{
return new CompositeProblemFilter(left, right, CompositionOperator.Or);
}
/**
* Construct a composite filter that negates a filter's decision to accept.
*/
public static IProblemFilter not(IProblemFilter filter)
{
return new CompositeProblemFilter(filter, null, CompositionOperator.Not);
}
}