org.mvel2.ast.TypeCast Maven / Gradle / Ivy
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With inspiration from other libraries
/**
* MVEL 2.0
* Copyright (C) 2007 The Codehaus
* Mike Brock, Dhanji Prasanna, John Graham, Mark Proctor
*
* Licensed 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.
*/
package org.mvel2.ast;
import org.mvel2.CompileException;
import org.mvel2.ParserContext;
import org.mvel2.compiler.ExecutableStatement;
import org.mvel2.integration.VariableResolverFactory;
import static org.mvel2.DataConversion.canConvert;
import static org.mvel2.DataConversion.convert;
import static org.mvel2.MVEL.eval;
import static org.mvel2.util.ParseTools.subCompileExpression;
import static org.mvel2.util.ReflectionUtil.isAssignableFrom;
public class TypeCast extends ASTNode {
private ExecutableStatement statement;
private boolean widen;
public TypeCast(char[] expr, int start, int offset, Class cast, int fields, ParserContext pCtx) {
super(pCtx);
this.egressType = cast;
this.expr = expr;
this.start = start;
this.offset = offset;
if ((fields & COMPILE_IMMEDIATE) != 0) {
if ((statement = (ExecutableStatement) subCompileExpression(expr, start, offset, pCtx))
.getKnownEgressType() != Object.class
&& !canConvert(cast, statement.getKnownEgressType())) {
if (canCast(statement.getKnownEgressType(), cast)) {
widen = true;
}
else {
throw new CompileException("unable to cast type: "
+ statement.getKnownEgressType() + "; to: " + cast, expr, start);
}
}
}
}
private boolean canCast(Class from, Class to) {
return isAssignableFrom(from, to) || (from.isInterface() && interfaceAssignable(from, to));
}
private boolean interfaceAssignable(Class from, Class to) {
for (Class c : from.getInterfaces()) {
if (c.isAssignableFrom(to)) return true;
}
return false;
}
public Object getReducedValueAccelerated(Object ctx, Object thisValue, VariableResolverFactory factory) {
//noinspection unchecked
return widen ? typeCheck(statement.getValue(ctx, thisValue, factory), egressType) : convert(statement.getValue(ctx, thisValue, factory), egressType);
}
public Object getReducedValue(Object ctx, Object thisValue, VariableResolverFactory factory) {
//noinspection unchecked
return widen ? typeCheck(eval(expr, start, offset, ctx, factory), egressType) :
convert(eval(expr, start, offset, ctx, factory), egressType);
}
private static Object typeCheck(Object inst, Class type) {
if (inst == null) return null;
if (type.isInstance(inst)) {
return inst;
}
else {
throw new ClassCastException(inst.getClass().getName() + " cannot be cast to: " + type.getClass().getName());
}
}
public ExecutableStatement getStatement() {
return statement;
}
}