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//========================================================================
//Copyright 2012 David Yu
//------------------------------------------------------------------------
//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.
//========================================================================
package io.protostuff.runtime;
/**
* A filter for the fields that need to be included.
*
* @author David Yu
* @created Nov 9, 2012
*/
public interface Predicate
{
/**
* Returns true if the field is included.
*/
public boolean apply(Field f);
/**
* Returns true if the field is included.
*
* The predicate logic can be dynamic based on the contents of the message.
*/
public boolean apply(Field f, Object message);
public interface Factory
{
/**
* Creates a new predicate based from the args.
*/
public Predicate create(String[] args);
}
/**
* A predicate that includes only a single field with the provided number.
*/
public static final class EQ implements Predicate, Predicate.Factory
{
final int num;
EQ(int num)
{
this.num = num;
}
@Override
public boolean apply(Field f)
{
return f.number == num;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number == num;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* A predicate that includes all fields except the provided number.
*/
public static final class NOTEQ implements Predicate, Predicate.Factory
{
final int num;
NOTEQ(int num)
{
this.num = num;
}
@Override
public boolean apply(Field f)
{
return f.number != num;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number != num;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* A predicate that includes fields that are greater than the provider number.
*/
public static final class GT implements Predicate, Predicate.Factory
{
final int num;
GT(int num)
{
this.num = num;
}
@Override
public boolean apply(Field f)
{
return f.number > num;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number > num;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* A predicate that includes fields that are lesser than the provider number.
*/
public static final class LT implements Predicate, Predicate.Factory
{
final int num;
LT(int num)
{
this.num = num;
}
@Override
public boolean apply(Field f)
{
return f.number < num;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number < num;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* A predicate that includes fields if they are within range of the provided numbers, min and max.
*/
public static final class RANGE implements Predicate, Predicate.Factory
{
final int min, max;
RANGE(int min, int max)
{
this.min = min;
this.max = max;
}
@Override
public boolean apply(Field f)
{
return f.number >= min && f.number <= max;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number >= min && f.number <= max;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* The opposite of {@link RANGE}.
*/
public static final class NOTRANGE implements Predicate, Predicate.Factory
{
final int min, max;
NOTRANGE(int min, int max)
{
this.min = min;
this.max = max;
}
@Override
public boolean apply(Field f)
{
return f.number < min || f.number > max;
}
@Override
public boolean apply(Field f, Object message)
{
return f.number < min || f.number > max;
}
// instantiate this yourself and pass it to the view factory for re-use
@Override
public Predicate create(String[] args)
{
return this;
}
}
/**
* Built-in factories that filters based on the field number.
*/
public enum Factories implements Predicate.Factory
{
EQ
{
@Override
public Predicate create(String[] args)
{
return new Predicate.EQ(Integer.parseInt(args[0]));
}
},
NOTEQ
{
@Override
public Predicate create(String[] args)
{
return new Predicate.NOTEQ(Integer.parseInt(args[0]));
}
},
GT
{
@Override
public Predicate create(String[] args)
{
return new Predicate.GT(Integer.parseInt(args[0]));
}
},
LT
{
@Override
public Predicate create(String[] args)
{
return new Predicate.LT(Integer.parseInt(args[0]));
}
},
RANGE
{
@Override
public Predicate create(String[] args)
{
return new Predicate.RANGE(Integer.parseInt(args[0]),
Integer.parseInt(args[1]));
}
},
NOTRANGE
{
@Override
public Predicate create(String[] args)
{
return new Predicate.NOTRANGE(Integer.parseInt(args[0]),
Integer.parseInt(args[1]));
}
};
}
}