org.hibernate.criterion.SimpleProjection.java Source code

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Here is the source code for org.hibernate.criterion.SimpleProjection.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.criterion;

import org.hibernate.Criteria;
import org.hibernate.type.Type;

/**
 * A single-column projection that may be aliased
 *
 * @author Gavin King
 */
public abstract class SimpleProjection implements EnhancedProjection {
    private static final int NUM_REUSABLE_ALIASES = 40;
    private static final String[] REUSABLE_ALIASES = initializeReusableAliases();

    private static String[] initializeReusableAliases() {
        final String[] aliases = new String[NUM_REUSABLE_ALIASES];
        for (int i = 0; i < NUM_REUSABLE_ALIASES; i++) {
            aliases[i] = aliasForLocation(i);
        }
        return aliases;
    }

    private static String aliasForLocation(final int loc) {
        return "y" + loc + "_";
    }

    private static String getAliasForLocation(final int loc) {
        if (loc >= NUM_REUSABLE_ALIASES) {
            return aliasForLocation(loc);
        } else {
            return REUSABLE_ALIASES[loc];
        }
    }

    /**
     * Create an aliased form of this projection
     *
     * @param alias The alias to apply
     *
     * @return The aliased projection
     */
    public Projection as(String alias) {
        return Projections.alias(this, alias);
    }

    @Override
    public String[] getColumnAliases(String alias, int loc) {
        return null;
    }

    @Override
    public String[] getColumnAliases(String alias, int loc, Criteria criteria, CriteriaQuery criteriaQuery) {
        return getColumnAliases(alias, loc);
    }

    @Override
    public Type[] getTypes(String alias, Criteria criteria, CriteriaQuery criteriaQuery) {
        return null;
    }

    @Override
    public String[] getColumnAliases(int loc) {
        return new String[] { getAliasForLocation(loc) };
    }

    /**
     * Count the number of columns this projection uses.
     *
     * @param criteria The criteria
     * @param criteriaQuery The query
     *
     * @return The number of columns
     */
    public int getColumnCount(Criteria criteria, CriteriaQuery criteriaQuery) {
        final Type[] types = getTypes(criteria, criteriaQuery);
        int count = 0;
        for (Type type : types) {
            count += type.getColumnSpan(criteriaQuery.getFactory());
        }
        return count;
    }

    @Override
    public String[] getColumnAliases(int loc, Criteria criteria, CriteriaQuery criteriaQuery) {
        final int numColumns = getColumnCount(criteria, criteriaQuery);
        final String[] aliases = new String[numColumns];
        for (int i = 0; i < numColumns; i++) {
            aliases[i] = getAliasForLocation(loc);
            loc++;
        }
        return aliases;
    }

    @Override
    public String[] getAliases() {
        return new String[1];
    }

    @Override
    public String toGroupSqlString(Criteria criteria, CriteriaQuery criteriaQuery) {
        throw new UnsupportedOperationException("not a grouping projection");
    }

    @Override
    public boolean isGrouped() {
        return false;
    }

}