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/*
* Copyright 2017-2018 the original author or authors.
*
* 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 org.springframework.data.cassandra.core.query;
import java.util.Optional;
import org.springframework.data.cassandra.core.cql.CqlIdentifier;
import org.springframework.util.Assert;
/**
* Value object representing a column name. Column names can be expressed either through {@link CqlIdentifier} or a
* {@link String} literal. Using a String literal preserves case and is suitable to reference properties.
*
* Equality and hash code are based on {@link #toCql()} representation.
*
* Implementing classes must provide either {@link #getColumnName()} or {@link #getCqlIdentifier()}.
*
* @author Mark Paluch
* @see org.springframework.data.cassandra.core.cql.CqlIdentifier
* @since 2.0
*/
public abstract class ColumnName {
/**
* Create a {@link ColumnName} given {@link CqlIdentifier}. The resulting instance uses CQL identifier rules to
* identify column names (quoting, case-sensitivity).
*
* @param cqlIdentifier must not be {@literal null}.
* @return the {@link ColumnName} for {@link CqlIdentifier}
* @see CqlIdentifier
*/
public static ColumnName from(CqlIdentifier cqlIdentifier) {
Assert.notNull(cqlIdentifier, "Column name must not be null");
return new CqlIdentifierColumnName(cqlIdentifier);
}
/**
* Create a {@link ColumnName} given a string {@code columnName}. The resulting instance uses String rules to identify
* column names (case-sensitivity).
*
* @param columnName must not be {@literal null} or empty.
* @return the {@link ColumnName} for {@link CqlIdentifier}
*/
public static ColumnName from(String columnName) {
Assert.hasText(columnName, "Column name must not be null or empty");
return new StringColumnName(columnName);
}
/**
* @return the optional column name.
*/
public abstract Optional getColumnName();
/**
* @return the optional {@link CqlIdentifier}.
*/
public abstract Optional getCqlIdentifier();
/**
* Represent the column name as CQL.
*
* @return CQL representation of the column name.
*/
public abstract String toCql();
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.Criteria#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof ColumnName)) {
return false;
}
ColumnName that = (ColumnName) obj;
return toCql().equals(that.toCql());
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
int hashValue = 17;
hashValue = 37 * hashValue + toCql().hashCode();
return hashValue;
}
/**
* {@link String}-based column name representation. Preserves letter casing.
*
* @author Mark Paluch
*/
static class StringColumnName extends ColumnName {
private final String columnName;
StringColumnName(String columnName) {
this.columnName = columnName;
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#getColumnName()
*/
@Override
public Optional getColumnName() {
return Optional.of(columnName);
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#getCqlIdentifier()
*/
@Override
public Optional getCqlIdentifier() {
return Optional.empty();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#toCql()
*/
@Override
public String toCql() {
return this.columnName;
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return this.columnName;
}
}
/**
* {@link CqlIdentifier}-based column name representation. Follows {@link CqlIdentifier} comparison rules.
*
* @author Mark Paluch
*/
static class CqlIdentifierColumnName extends ColumnName {
private final CqlIdentifier cqlIdentifier;
CqlIdentifierColumnName(CqlIdentifier cqlIdentifier) {
this.cqlIdentifier = cqlIdentifier;
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#getColumnName()
*/
@Override
public Optional getColumnName() {
return Optional.empty();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#getCqlIdentifier()
*/
@Override
public Optional getCqlIdentifier() {
return Optional.of(this.cqlIdentifier);
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.core.query.ColumnName#toCql()
*/
@Override
public String toCql() {
return this.cqlIdentifier.toCql();
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return this.cqlIdentifier.toString();
}
}
}