android.databinding.tool.expr.MathExpr Maven / Gradle / Ivy
/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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 android.databinding.tool.expr;
import android.databinding.tool.reflection.ModelAnalyzer;
import android.databinding.tool.reflection.ModelClass;
import android.databinding.tool.util.Preconditions;
import android.databinding.tool.writer.KCode;
import java.util.List;
public class MathExpr extends Expr {
final String mOp;
MathExpr(Expr left, String op, Expr right) {
super(left, right);
mOp = op;
}
@Override
protected String computeUniqueKey() {
return join(getLeft().getUniqueKey(), mOp, getRight().getUniqueKey());
}
@Override
protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
if ("+".equals(mOp)) {
// TODO we need upper casting etc.
if (getLeft().getResolvedType().isString()
|| getRight().getResolvedType().isString()) {
return modelAnalyzer.findClass(String.class);
}
}
return modelAnalyzer.findCommonParentOf(getLeft().getResolvedType(),
getRight().getResolvedType());
}
@Override
protected List constructDependencies() {
return constructDynamicChildrenDependencies();
}
public Expr getLeft() {
return getChildren().get(0);
}
public Expr getRight() {
return getChildren().get(1);
}
@Override
protected KCode generateCode() {
return new KCode().app("(", getLeft().toCode())
.app(") ")
.app(mOp)
.app(" (", getRight().toCode())
.app(")");
}
@Override
public String getInvertibleError() {
if (mOp.equals("%")) {
return "The modulus operator (%) is not supported in two-way binding.";
} else if (getResolvedType().isString()) {
return "String concatenation operator (+) is not supported in two-way binding.";
}
if (!getLeft().isDynamic()) {
return getRight().getInvertibleError();
} else if (!getRight().isDynamic()) {
return getLeft().getInvertibleError();
} else {
return "Arithmetic operator " + mOp + " is not supported with two dynamic expressions.";
}
}
@Override
public Expr generateInverse(ExprModel model, Expr value, String bindingClassName) {
final Expr left = getLeft();
final Expr right = getRight();
Preconditions.check(left.isDynamic() ^ right.isDynamic(), "Two-way binding of a math " +
"operations requires A signle dynamic expression. Neither or both sides are " +
"dynamic: (%s) %s (%s)", left, mOp, right);
final Expr constExpr = (left.isDynamic() ? right : left).cloneToModel(model);
final Expr newValue;
switch (mOp.charAt(0)) {
case '+': // const + x = value => x = value - const
newValue = model.math(value, "-", constExpr);
break;
case '*': // const * x = value => x = value / const
newValue = model.math(value, "/", constExpr);
break;
case '-':
if (!left.isDynamic()) { // const - x = value => x = const - (value)
newValue = model.math(constExpr, "-", value);
} else { // x - const = value => x = value + const)
newValue = model.math(value, "+", constExpr);
}
break;
case '/':
if (!left.isDynamic()) { // const / x = value => x = const / value
newValue = model.math(constExpr, "/", value);
} else { // x / const = value => x = value * const
newValue = model.math(value, "*", constExpr);
}
break;
default:
throw new IllegalStateException("Invalid math operation is not invertible: " + mOp);
}
final Expr varExpr = left.isDynamic() ? left : right;
return varExpr.generateInverse(model, newValue, bindingClassName);
}
@Override
public Expr cloneToModel(ExprModel model) {
return model.math(getLeft().cloneToModel(model), mOp, getRight().cloneToModel(model));
}
@Override
public String toString() {
return "(" + getLeft() + ") " + mOp + " (" + getRight() + ")";
}
}
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