src/main/java/org/apache/commons/ognl/ASTTest.java

package org.apache.commons.ognl;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * 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
 * 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.
 */

import org.apache.commons.ognl.enhance.UnsupportedCompilationException;

/**
 * $Id$
 */
class ASTTest
    extends ExpressionNode
{
    public ASTTest( int id )
    {
        super( id );
    }

    public ASTTest( OgnlParser p, int id )
    {
        super( p, id );
    }

    protected Object getValueBody( OgnlContext context, Object source )
        throws OgnlException
    {
        Object test = children[0].getValue( context, source );
        int branch = OgnlOps.booleanValue( test ) ? 1 : 2;
        return children[branch].getValue( context, source );
    }

    protected void setValueBody( OgnlContext context, Object target, Object value )
        throws OgnlException
    {
        Object test = children[0].getValue( context, target );
        int branch = OgnlOps.booleanValue( test ) ? 1 : 2;
        children[branch].setValue( context, target, value );
    }

    public String getExpressionOperator( int index )
    {
        return ( index == 1 ) ? "?" : ":";
    }

    public String toGetSourceString( OgnlContext context, Object target )
    {
        if ( target == null )
        {
            throw new UnsupportedCompilationException( "evaluation resulted in null expression." );
        }

        if ( children.length != 3 )
        {
            throw new UnsupportedCompilationException( "Can only compile test expressions with two children."
                + children.length );
        }

        String result = "";

        try
        {

            String first = OgnlRuntime.getChildSource( context, target, children[0] );
            if ( !OgnlRuntime.isBoolean( first ) && !context.getCurrentType().isPrimitive() )
            {
                first = OgnlRuntime.getCompiler( context ).createLocalReference( context, first, context.getCurrentType() );
            }

            if ( ExpressionNode.class.isInstance( children[0] ) )
            {
                first = "(" + first + ")";
            }

            String second = OgnlRuntime.getChildSource( context, target, children[1] );
            Class secondType = context.getCurrentType();

            if ( !OgnlRuntime.isBoolean( second ) && !context.getCurrentType().isPrimitive() )
            {
                second = OgnlRuntime.getCompiler( context ).createLocalReference( context, second, context.getCurrentType() );
            }

            if ( ExpressionNode.class.isInstance( children[1] ) )
            {
                second = "(" + second + ")";
            }

            String third = OgnlRuntime.getChildSource( context, target, children[2] );
            Class thirdType = context.getCurrentType();

            if ( !OgnlRuntime.isBoolean( third ) && !context.getCurrentType().isPrimitive() )
            {
                third = OgnlRuntime.getCompiler( context ).createLocalReference( context, third, context.getCurrentType() );

            }

            if ( ExpressionNode.class.isInstance( children[2] ) )
            {
                third = "(" + third + ")";
            }

            boolean mismatched =
                ( secondType.isPrimitive( ) && !thirdType.isPrimitive( ) ) || ( !secondType.isPrimitive( )
                    && thirdType.isPrimitive( ) );

            result += "org.apache.commons.ognl.OgnlOps.booleanValue(" + first + ")";

            result += " ? ";

            result += ( mismatched ? " ($w) " : "" ) + second;
            result += " : ";

            result += ( mismatched ? " ($w) " : "" ) + third;

            context.setCurrentObject( target );
            context.setCurrentType( mismatched ? Object.class : secondType );

            return result;

        }
        catch ( NullPointerException e )
        {

            // expected to happen in some instances
            throw new UnsupportedCompilationException( "evaluation resulted in null expression." );
        }
        catch ( Throwable t )
        {
            throw OgnlOps.castToRuntime( t );
        }
    }

    public <R, P> R accept( NodeVisitor<? extends R, ? super P> visitor, P data )
        throws OgnlException
    {
        return visitor.visit( this, data );
    }
}