eu.interedition.text.util.SQL.java Source code

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Here is the source code for eu.interedition.text.util.SQL.java

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/*
 * #%L
 * Text: A text model with range-based markup via standoff annotations.
 * %%
 * Copyright (C) 2010 - 2011 The Interedition Development Group
 * %%
 * 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.
 * #L%
 */
package eu.interedition.text.util;

import com.google.common.collect.AbstractIterator;
import org.hibernate.Criteria;
import org.hibernate.ScrollMode;
import org.hibernate.ScrollableResults;

import java.util.Iterator;

/**
 * @author <a href="http://gregor.middell.net/" title="Homepage">Gregor Middell</a>
 */
public class SQL {
    public static String select(String tableName, String... columns) {
        final StringBuilder select = new StringBuilder();
        for (int cc = 0; cc < columns.length; cc++) {
            final String column = columns[cc];
            select.append(cc == 0 ? "" : ", ");
            select.append(tableName).append(".").append(column).append(" as ").append(tableName).append("_")
                    .append(column);
        }
        return select.toString();
    }

    public static String inClause(Iterable<?> params) {
        final StringBuilder sql = new StringBuilder(" in (");
        for (Iterator<?> it = params.iterator(); it.hasNext();) {
            it.next();
            sql.append("?").append(it.hasNext() ? ", " : "");
        }
        sql.append(")");
        return sql.toString();
    }

    public static <T> Iterable<T> iterate(final Criteria c, Class<T> type) {
        return new Iterable<T>() {
            @Override
            public Iterator<T> iterator() {
                return new AbstractIterator<T>() {

                    final ScrollableResults results = c.scroll(ScrollMode.FORWARD_ONLY);

                    @Override
                    @SuppressWarnings("unchecked")
                    protected T computeNext() {
                        return (results.next() ? (T) results.get()[0] : endOfData());
                    }
                };
            }
        };
    }
}