/*
* 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.cassandra.db.marshal;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import org.apache.cassandra.cql3.CQL3Type;
import org.apache.cassandra.exceptions.SyntaxException;
import org.apache.cassandra.serializers.TypeSerializer;
import org.apache.cassandra.serializers.MarshalException;
import org.github.jamm.Unmetered;
/**
* Specifies a Comparator for a specific type of ByteBuffer.
*
* Note that empty ByteBuffer are used to represent "start at the beginning"
* or "stop at the end" arguments to get_slice, so the Comparator
* should always handle those values even if they normally do not
* represent a valid ByteBuffer for the type being compared.
*/
@Unmetered
public abstract class AbstractType<T> implements Comparator<ByteBuffer>
{
public final Comparator<ByteBuffer> reverseComparator;
protected AbstractType()
{
reverseComparator = new Comparator<ByteBuffer>()
{
public int compare(ByteBuffer o1, ByteBuffer o2)
{
if (o1.remaining() == 0)
{
return o2.remaining() == 0 ? 0 : -1;
}
if (o2.remaining() == 0)
{
return 1;
}
return AbstractType.this.compare(o2, o1);
}
};
}
public T compose(ByteBuffer bytes)
{
return getSerializer().deserialize(bytes);
}
public ByteBuffer decompose(T value)
{
return getSerializer().serialize(value);
}
/** get a string representation of the bytes suitable for log messages */
public String getString(ByteBuffer bytes)
{
TypeSerializer<T> serializer = getSerializer();
serializer.validate(bytes);
return serializer.toString(serializer.deserialize(bytes));
}
/** get a byte representation of the given string. */
public abstract ByteBuffer fromString(String source) throws MarshalException;
/** for compatibility with TimeUUID in CQL2. See TimeUUIDType (that overrides it). */
public ByteBuffer fromStringCQL2(String source) throws MarshalException
{
return fromString(source);
}
/* validate that the byte array is a valid sequence for the type we are supposed to be comparing */
public void validate(ByteBuffer bytes) throws MarshalException
{
getSerializer().validate(bytes);
}
/**
* Validate cell value. Unlike {@linkplain #validate(java.nio.ByteBuffer)},
* cell value is passed to validate its content.
* Usually, this is the same as validate except collection.
*
* @param cellValue ByteBuffer representing cell value
* @throws MarshalException
*/
public void validateCellValue(ByteBuffer cellValue) throws MarshalException
{
validate(cellValue);
}
/* Most of our internal type should override that. */
public CQL3Type asCQL3Type()
{
return new CQL3Type.Custom(this);
}
public abstract TypeSerializer<T> getSerializer();
/* convenience method */
public String getString(Collection<ByteBuffer> names)
{
StringBuilder builder = new StringBuilder();
for (ByteBuffer name : names)
{
builder.append(getString(name)).append(",");
}
return builder.toString();
}
public boolean isCounter()
{
return false;
}
public static AbstractType<?> parseDefaultParameters(AbstractType<?> baseType, TypeParser parser) throws SyntaxException
{
Map<String, String> parameters = parser.getKeyValueParameters();
String reversed = parameters.get("reversed");
if (reversed != null && (reversed.isEmpty() || reversed.equals("true")))
{
return ReversedType.getInstance(baseType);
}
else
{
return baseType;
}
}
/**
* Returns true if this comparator is compatible with the provided
* previous comparator, that is if previous can safely be replaced by this.
* A comparator cn should be compatible with a previous one cp if forall columns c1 and c2,
* if cn.validate(c1) and cn.validate(c2) and cn.compare(c1, c2) == v,
* then cp.validate(c1) and cp.validate(c2) and cp.compare(c1, c2) == v.
*
* Note that a type should be compatible with at least itself and when in
* doubt, keep the default behavior of not being compatible with any other comparator!
*/
public boolean isCompatibleWith(AbstractType<?> previous)
{
return this.equals(previous);
}
/**
* Returns true if values of the other AbstractType can be read and "reasonably" interpreted by the this
* AbstractType. Note that this is a weaker version of isCompatibleWith, as it does not require that both type
* compare values the same way.
*
* The restriction on the other type being "reasonably" interpreted is to prevent, for example, IntegerType from
* being compatible with all other types. Even though any byte string is a valid IntegerType value, it doesn't
* necessarily make sense to interpret a UUID or a UTF8 string as an integer.
*
* Note that a type should be compatible with at least itself.
*/
public boolean isValueCompatibleWith(AbstractType<?> otherType)
{
return isValueCompatibleWithInternal((otherType instanceof ReversedType) ? ((ReversedType) otherType).baseType : otherType);
}
/**
* Needed to handle ReversedType in value-compatibility checks. Subclasses should implement this instead of
* isValueCompatibleWith().
*/
protected boolean isValueCompatibleWithInternal(AbstractType<?> otherType)
{
return isCompatibleWith(otherType);
}
/**
* @return true IFF the byte representation of this type can be compared unsigned
* and always return the same result as calling this object's compare or compareCollectionMembers methods
*/
public boolean isByteOrderComparable()
{
return false;
}
/**
* An alternative comparison function used by CollectionsType in conjunction with CompositeType.
*
* This comparator is only called to compare components of a CompositeType. It gets the value of the
* previous component as argument (or null if it's the first component of the composite).
*
* Unless you're doing something very similar to CollectionsType, you shouldn't override this.
*/
public int compareCollectionMembers(ByteBuffer v1, ByteBuffer v2, ByteBuffer collectionName)
{
return compare(v1, v2);
}
/**
* An alternative validation function used by CollectionsType in conjunction with CompositeType.
*
* This is similar to the compare function above.
*/
public void validateCollectionMember(ByteBuffer bytes, ByteBuffer collectionName) throws MarshalException
{
validate(bytes);
}
public boolean isCollection()
{
return false;
}
public boolean isMultiCell()
{
return false;
}
public AbstractType<?> freeze()
{
return this;
}
/**
* @param ignoreFreezing if true, the type string will not be wrapped with FrozenType(...), even if this type is frozen.
*/
public String toString(boolean ignoreFreezing)
{
return this.toString();
}
/**
* The number of subcomponents this type has.
* This is always 1, i.e. the type has only itself as "subcomponents", except for CompositeType.
*/
public int componentsCount()
{
return 1;
}
/**
* Return a list of the "subcomponents" this type has.
* This always return a singleton list with the type itself except for CompositeType.
*/
public List<AbstractType<?>> getComponents()
{
return Collections.<AbstractType<?>>singletonList(this);
}
/**
* This must be overriden by subclasses if necessary so that for any
* AbstractType, this == TypeParser.parse(toString()).
*
* Note that for backwards compatibility this includes the full classname.
* For CQL purposes the short name is fine.
*/
@Override
public String toString()
{
return getClass().getName();
}
}