cayenne-server/src/main/java/org/apache/cayenne/query/DeleteBatchQuery.java

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 *  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
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 *    https://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cayenne.query;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.function.Supplier;

import org.apache.cayenne.map.DbAttribute;
import org.apache.cayenne.map.DbEntity;

/**
 * Batched delete query.
 * 
 */
public class DeleteBatchQuery extends BatchQuery {

    protected boolean usingOptimisticLocking;

    private Collection<String> nullQualifierNames;

    /**
     * Creates new DeleteBatchQuery.
     * 
     * @param dbEntity
     *            Table or view to delete.
     * @param qualifierAttributes
     *            DbAttributes used in the WHERE clause.
     * @param nullQualifierNames
     *            DbAttribute names in the WHERE clause that have null values.
     * @param batchCapacity
     *            Estimated size of the batch.
     */
    public DeleteBatchQuery(DbEntity dbEntity, List<DbAttribute> qualifierAttributes,
            Collection<String> nullQualifierNames, int batchCapacity) {

        super(dbEntity, qualifierAttributes, batchCapacity);

        if (nullQualifierNames == null) {
            throw new NullPointerException("Null 'nullQualifierNames'");
        }

        this.nullQualifierNames = nullQualifierNames;
    }

    /**
     * Returns true if a given attribute always has a null value in the batch.
     * 
     * @since 1.2
     */
    public boolean isNull(DbAttribute attribute) {
        return nullQualifierNames.contains(attribute.getName());
    }

    /**
     * Returns true if the batch query uses optimistic locking.
     * 
     * @since 1.2
     */
    @Override
    public boolean isUsingOptimisticLocking() {
        return usingOptimisticLocking;
    }

    /**
     * @since 1.2
     */
    public void setUsingOptimisticLocking(boolean usingOptimisticLocking) {
        this.usingOptimisticLocking = usingOptimisticLocking;
    }

    public void add(Map<String, Object> dataObjectId) {

        rows.add(new BatchQueryRow(null, dataObjectId) {
            @Override
            public Object getValue(int i) {
                Object value = qualifier.get(dbAttributes.get(i).getName());
                if(value instanceof Supplier) {
                    return ((Supplier) value).get();
                }
                return value;
            }
        });
    }
}