Hibernate example source code file (QueryKey.java)

This example Hibernate source code file (QueryKey.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

cacheableresulttransformer, integer, integer, io, map, object, object, override, querykey, querykey, set, string, string, stringbuilder, type, util

The Hibernate QueryKey.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.cache.spi;

import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import java.util.Set;

import org.hibernate.engine.spi.QueryParameters;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.engine.spi.TypedValue;
import org.hibernate.internal.util.collections.CollectionHelper;
import org.hibernate.internal.util.compare.EqualsHelper;
import org.hibernate.transform.CacheableResultTransformer;
import org.hibernate.type.Type;

/**
 * A key that identifies a particular query with bound parameter values.  This is the object Hibernate uses
 * as its key into its query cache.
 *
 * @author Gavin King
 * @author Steve Ebersole
 */
public class QueryKey implements Serializable {
	private final String sqlQueryString;
	private final Type[] positionalParameterTypes;
	private final Object[] positionalParameterValues;
	private final Map namedParameters;
	private final Integer firstRow;
	private final Integer maxRows;
	private final String tenantIdentifier;
	private final Set filterKeys;

	// the user provided resulttransformer, not the one used with "select new". Here to avoid mangling
	// transformed/non-transformed results.
	private final CacheableResultTransformer customTransformer;

	/**
	 * For performance reasons, the hashCode is cached; however, it is marked transient so that it can be
	 * recalculated as part of the serialization process which allows distributed query caches to work properly.
	 */
	private transient int hashCode;

	/**
	 * Generates a QueryKey.
	 *
	 * @param queryString The sql query string.
	 * @param queryParameters The query parameters
	 * @param filterKeys The keys of any enabled filters.
	 * @param session The current session.
	 * @param customTransformer The result transformer; should be
	 *            null if data is not transformed before being cached.
	 *
	 * @return The generate query cache key.
	 */
	public static QueryKey generateQueryKey(
			String queryString,
			QueryParameters queryParameters,
			Set filterKeys,
			SessionImplementor session,
			CacheableResultTransformer customTransformer) {
		// disassemble positional parameters
		final int positionalParameterCount = queryParameters.getPositionalParameterTypes().length;
		final Type[] types = new Type[positionalParameterCount];
		final Object[] values = new Object[positionalParameterCount];
		for ( int i = 0; i < positionalParameterCount; i++ ) {
			types[i] = queryParameters.getPositionalParameterTypes()[i];
			values[i] = types[i].disassemble( queryParameters.getPositionalParameterValues()[i], session, null );
		}

		// disassemble named parameters
		final Map<String,TypedValue> namedParameters;
		if ( queryParameters.getNamedParameters() == null ) {
			namedParameters = null;
		}
		else {
			namedParameters = CollectionHelper.mapOfSize( queryParameters.getNamedParameters().size() );
			for ( Map.Entry<String,TypedValue> namedParameterEntry : queryParameters.getNamedParameters().entrySet() ) {
				namedParameters.put(
						namedParameterEntry.getKey(),
						new TypedValue(
								namedParameterEntry.getValue().getType(),
								namedParameterEntry.getValue().getType().disassemble(
										namedParameterEntry.getValue().getValue(),
										session,
										null
								)
						)
				);
			}
		}

		// decode row selection...
		final RowSelection selection = queryParameters.getRowSelection();
		final Integer firstRow;
		final Integer maxRows;
		if ( selection != null ) {
			firstRow = selection.getFirstRow();
			maxRows = selection.getMaxRows();
		}
		else {
			firstRow = null;
			maxRows = null;
		}

		return new QueryKey(
				queryString,
				types,
				values,
				namedParameters,
				firstRow,
				maxRows,
				filterKeys,
				session.getTenantIdentifier(),
				customTransformer
		);
	}

	/**
	 * Package-protected constructor.
	 *
	 * @param sqlQueryString The sql query string.
	 * @param positionalParameterTypes Positional parameter types.
	 * @param positionalParameterValues Positional parameter values.
	 * @param namedParameters Named parameters.
	 * @param firstRow First row selection, if any.
	 * @param maxRows Max-rows selection, if any.
	 * @param filterKeys Enabled filter keys, if any.
	 * @param customTransformer Custom result transformer, if one.
	 * @param tenantIdentifier The tenant identifier in effect for this query, or {@code null}
	 */
	QueryKey(
			String sqlQueryString,
			Type[] positionalParameterTypes,
			Object[] positionalParameterValues,
			Map namedParameters,
			Integer firstRow,
			Integer maxRows,
			Set filterKeys,
			String tenantIdentifier,
			CacheableResultTransformer customTransformer) {
		this.sqlQueryString = sqlQueryString;
		this.positionalParameterTypes = positionalParameterTypes;
		this.positionalParameterValues = positionalParameterValues;
		this.namedParameters = namedParameters;
		this.firstRow = firstRow;
		this.maxRows = maxRows;
		this.tenantIdentifier = tenantIdentifier;
		this.filterKeys = filterKeys;
		this.customTransformer = customTransformer;
		this.hashCode = generateHashCode();
	}

	public CacheableResultTransformer getResultTransformer() {
		return customTransformer;
	}

	/**
	 * Deserialization hook used to re-init the cached hashcode which is needed for proper clustering support.
	 *
	 * @param in The object input stream.
	 *
	 * @throws IOException Thrown by normal deserialization
	 * @throws ClassNotFoundException Thrown by normal deserialization
	 */
	private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
		in.defaultReadObject();
		this.hashCode = generateHashCode();
	}

	private int generateHashCode() {
		int result = 13;
		result = 37 * result + ( firstRow==null ? 0 : firstRow.hashCode() );
		result = 37 * result + ( maxRows==null ? 0 : maxRows.hashCode() );
		for ( int i=0; i< positionalParameterValues.length; i++ ) {
			result = 37 * result + ( positionalParameterValues[i]==null ? 0 : positionalParameterTypes[i].getHashCode( positionalParameterValues[i] ) );
		}
		result = 37 * result + ( namedParameters==null ? 0 : namedParameters.hashCode() );
		result = 37 * result + ( filterKeys ==null ? 0 : filterKeys.hashCode() );
		result = 37 * result + ( customTransformer==null ? 0 : customTransformer.hashCode() );
		result = 37 * result + ( tenantIdentifier==null ? 0 : tenantIdentifier.hashCode() );
		result = 37 * result + sqlQueryString.hashCode();
		return result;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
    public boolean equals(Object other) {
		if ( !( other instanceof QueryKey ) ) {
			return false;
		}
		QueryKey that = ( QueryKey ) other;
		if ( !sqlQueryString.equals( that.sqlQueryString ) ) {
			return false;
		}
		if ( !EqualsHelper.equals( firstRow, that.firstRow ) || !EqualsHelper.equals( maxRows, that.maxRows ) ) {
			return false;
		}
		if ( !EqualsHelper.equals( customTransformer, that.customTransformer ) ) {
			return false;
		}
		if ( positionalParameterTypes == null ) {
			if ( that.positionalParameterTypes != null ) {
				return false;
			}
		}
		else {
			if ( that.positionalParameterTypes == null ) {
				return false;
			}
			if ( positionalParameterTypes.length != that.positionalParameterTypes.length ) {
				return false;
			}
			for ( int i = 0; i < positionalParameterTypes.length; i++ ) {
				if ( positionalParameterTypes[i].getReturnedClass() != that.positionalParameterTypes[i].getReturnedClass() ) {
					return false;
				}
				if ( !positionalParameterTypes[i].isEqual( positionalParameterValues[i], that.positionalParameterValues[i] ) ) {
					return false;
				}
			}
		}

		return EqualsHelper.equals( filterKeys, that.filterKeys )
				&& EqualsHelper.equals( namedParameters, that.namedParameters )
				&& EqualsHelper.equals( tenantIdentifier, that.tenantIdentifier );
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
    public int hashCode() {
		return hashCode;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
    public String toString() {
		StringBuilder buffer = new StringBuilder( "sql: " ).append( sqlQueryString );
		if ( positionalParameterValues != null ) {
			buffer.append( "; parameters: " );
			for ( Object positionalParameterValue : positionalParameterValues ) {
				buffer.append( positionalParameterValue ).append( ", " );
			}
		}
		if ( namedParameters != null ) {
			buffer.append( "; named parameters: " ).append( namedParameters );
		}
		if ( filterKeys != null ) {
			buffer.append( "; filterKeys: " ).append( filterKeys );
		}
		if ( firstRow != null ) {
			buffer.append( "; first row: " ).append( firstRow );
		}
		if ( maxRows != null ) {
			buffer.append( "; max rows: " ).append( maxRows );
		}
		if ( customTransformer != null ) {
			buffer.append( "; transformer: " ).append( customTransformer );
		}
		return buffer.toString();
	}

}