Hibernate example source code file (ConstructorNode.java)

This example Hibernate source code file (ConstructorNode.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

class, constructor, constructornode, override, reflection, selectexpression, selectexpression, semanticexception, semanticexception, string, string, type, type, unable, unsupportedoperationexception, util

The Hibernate ConstructorNode.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.hql.internal.ast.tree;

import java.lang.reflect.Constructor;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import antlr.SemanticException;
import antlr.collections.AST;

import org.hibernate.PropertyNotFoundException;
import org.hibernate.QueryException;
import org.hibernate.hql.internal.ast.DetailedSemanticException;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.internal.util.StringHelper;
import org.hibernate.transform.AliasToBeanConstructorResultTransformer;
import org.hibernate.transform.ResultTransformer;
import org.hibernate.transform.Transformers;
import org.hibernate.type.Type;

/**
 * Represents a constructor (new) in a SELECT.
 *
 * @author josh
 */
public class ConstructorNode extends SelectExpressionList implements AggregatedSelectExpression {
	private Class resultType;
	private Constructor constructor;
	private Type[] constructorArgumentTypes;
	private boolean isMap;
	private boolean isList;

	public ResultTransformer getResultTransformer() {
		if ( constructor != null ) {
			return new AliasToBeanConstructorResultTransformer( constructor );
		}
		else if ( isMap ) {
			return Transformers.ALIAS_TO_ENTITY_MAP;
		}
		else if ( isList ) {
			return Transformers.TO_LIST;
		}
		throw new QueryException( "Unable to determine proper dynamic-instantiation tranformer to use." );
	}

	private String[] aggregatedAliases;

	public String[] getAggregatedAliases() {
		if ( aggregatedAliases == null ) {
			aggregatedAliases = buildAggregatedAliases();
		}
		return aggregatedAliases;
	}

	private String[] buildAggregatedAliases() {
		SelectExpression[] selectExpressions = collectSelectExpressions();
		String[] aliases = new String[selectExpressions.length] ;
		for ( int i=0; i<selectExpressions.length; i++ ) {
			String alias = selectExpressions[i].getAlias();
			aliases[i] = alias==null ? Integer.toString(i) : alias;
		}
		return aliases;
	}

	public void setScalarColumn(int i) throws SemanticException {
		SelectExpression[] selectExpressions = collectSelectExpressions();
		// Invoke setScalarColumnText on each constructor argument.
		for ( int j = 0; j < selectExpressions.length; j++ ) {
			SelectExpression selectExpression = selectExpressions[j];
			selectExpression.setScalarColumn( j );
		}
	}

	public int getScalarColumnIndex() {
		return -1;
	}

	public void setScalarColumnText(int i) throws SemanticException {
		SelectExpression[] selectExpressions = collectSelectExpressions();
		// Invoke setScalarColumnText on each constructor argument.
		for ( int j = 0; j < selectExpressions.length; j++ ) {
			SelectExpression selectExpression = selectExpressions[j];
			selectExpression.setScalarColumnText( j );
		}
	}

	@Override
    protected AST getFirstSelectExpression() {
		// Collect the select expressions, skip the first child because it is the class name.
		return getFirstChild().getNextSibling();
	}

	@Override
	public Class getAggregationResultType() {
		return resultType;
	}

	/**
	 * @deprecated (tell clover to ignore this method)
	 */
	@Deprecated
    @Override
    public Type getDataType() {
/*
		// Return the type of the object created by the constructor.
		AST firstChild = getFirstChild();
		String text = firstChild.getText();
		if ( firstChild.getType() == SqlTokenTypes.DOT ) {
			DotNode dot = ( DotNode ) firstChild;
			text = dot.getPath();
		}
		return getSessionFactoryHelper().requireEntityType( text );
*/
		throw new UnsupportedOperationException( "getDataType() is not supported by ConstructorNode!" );
	}

	public void prepare() throws SemanticException {
		constructorArgumentTypes = resolveConstructorArgumentTypes();
		String path = ( ( PathNode ) getFirstChild() ).getPath();
		if ( "map".equals( path.toLowerCase() ) ) {
			isMap = true;
			resultType = Map.class;
		}
		else if ( "list".equals( path.toLowerCase() ) ) {
			isList = true;
			resultType = List.class;
		}
		else {
			constructor = resolveConstructor( path );
			resultType = constructor.getDeclaringClass();
		}
	}

	private Type[] resolveConstructorArgumentTypes() throws SemanticException {
		SelectExpression[] argumentExpressions = collectSelectExpressions();
		if ( argumentExpressions == null ) {
			// return an empty Type array
			return new Type[]{};
		}

		Type[] types = new Type[argumentExpressions.length];
		for ( int x = 0; x < argumentExpressions.length; x++ ) {
			types[x] = argumentExpressions[x].getDataType();
		}
		return types;
	}

	private Constructor resolveConstructor(String path) throws SemanticException {
		String importedClassName = getSessionFactoryHelper().getImportedClassName( path );
		String className = StringHelper.isEmpty( importedClassName ) ? path : importedClassName;
		if ( className == null ) {
			throw new SemanticException( "Unable to locate class [" + path + "]" );
		}
		try {
			Class holderClass = ReflectHelper.classForName( className );
			return ReflectHelper.getConstructor( holderClass, constructorArgumentTypes );
		}
		catch ( ClassNotFoundException e ) {
			throw new DetailedSemanticException( "Unable to locate class [" + className + "]", e );
		}
		catch ( PropertyNotFoundException e ) {
			// this is the exception returned by ReflectHelper.getConstructor() if it cannot
			// locate an appropriate constructor
			throw new DetailedSemanticException( "Unable to locate appropriate constructor on class [" + className + "]", e );
		}
	}

	public Constructor getConstructor() {
		return constructor;
	}

	public List getConstructorArgumentTypeList() {
		return Arrays.asList( constructorArgumentTypes );
	}

	public List getAggregatedSelectionTypeList() {
		return getConstructorArgumentTypeList();
	}

	public FromElement getFromElement() {
		return null;
	}

	public boolean isConstructor() {
		return true;
	}

	public boolean isReturnableEntity() throws SemanticException {
		return false;
	}

	public boolean isScalar() {
		// Constructors are always considered scalar results.
		return true;
	}

	public void setAlias(String alias) {
		throw new UnsupportedOperationException("constructor may not be aliased");
	}

	public String getAlias() {
		throw new UnsupportedOperationException("constructor may not be aliased");
	}
}