OpString.java example

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Lucee-master
/**
 * Copyright (c) 2014, the Railo Company Ltd.
 * Copyright (c) 2015, Lucee Assosication Switzerland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */
package lucee.transformer.bytecode.op;

import lucee.transformer.TransformerException;
import lucee.transformer.bytecode.BytecodeContext;
import lucee.transformer.bytecode.expression.ExpressionBase;
import lucee.transformer.bytecode.util.Types;
import lucee.transformer.expression.ExprString;
import lucee.transformer.expression.Expression;
import lucee.transformer.expression.literal.Literal;

import org.objectweb.asm.Type;
import org.objectweb.asm.commons.Method;

public final class OpString extends ExpressionBase implements ExprString {
    
    private ExprString right;
    private ExprString left;

    // String concat (String)
    private final static Method METHOD_CONCAT = new Method("concat",
			Types.STRING,
			new Type[]{Types.STRING});
	private static final int MAX_SIZE = 65535;
    
    private OpString(Expression left, Expression right) {
        super(left.getFactory(),left.getStart(),right.getEnd());
        this.left=left.getFactory().toExprString(left);
        this.right=left.getFactory().toExprString(right);
    }

    public static ExprString toExprString(Expression left, Expression right, boolean concatStatic) {
        if(concatStatic && left instanceof Literal && right instanceof Literal) {
            String l = ((Literal)left).getString();
        	String r = ((Literal)right).getString();
        	if((l.length()+r.length())<=MAX_SIZE)return left.getFactory().createLitString(l.concat(r),left.getStart(),right.getEnd());
        }
        return new OpString(left,right);
    }

    @Override
    public Type _writeOut(BytecodeContext bc, int mode) throws TransformerException {
        left.writeOut(bc,MODE_REF);
        right.writeOut(bc,MODE_REF);
        bc.getAdapter().invokeVirtual(Types.STRING,METHOD_CONCAT);
        return Types.STRING;
    }
}