com.github.javaparser.ast.expr.LambdaExpr Maven / Gradle / Ivy
Show all versions of javaparser-core Show documentation
/*
* Copyright (C) 2007-2010 Júlio Vilmar Gesser.
* Copyright (C) 2011, 2013-2024 The JavaParser Team.
*
* This file is part of JavaParser.
*
* JavaParser can be used either under the terms of
* a) the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* b) the terms of the Apache License
*
* You should have received a copy of both licenses in LICENCE.LGPL and
* LICENCE.APACHE. Please refer to those files for details.
*
* JavaParser 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.
*/
package com.github.javaparser.ast.expr;
import static com.github.javaparser.utils.Utils.assertNotNull;
import com.github.javaparser.TokenRange;
import com.github.javaparser.ast.AllFieldsConstructor;
import com.github.javaparser.ast.Generated;
import com.github.javaparser.ast.Node;
import com.github.javaparser.ast.NodeList;
import com.github.javaparser.ast.body.Parameter;
import com.github.javaparser.ast.nodeTypes.NodeWithParameters;
import com.github.javaparser.ast.observer.ObservableProperty;
import com.github.javaparser.ast.stmt.BlockStmt;
import com.github.javaparser.ast.stmt.ExpressionStmt;
import com.github.javaparser.ast.stmt.ReturnStmt;
import com.github.javaparser.ast.stmt.Statement;
import com.github.javaparser.ast.visitor.CloneVisitor;
import com.github.javaparser.ast.visitor.GenericVisitor;
import com.github.javaparser.ast.visitor.VoidVisitor;
import com.github.javaparser.metamodel.DerivedProperty;
import com.github.javaparser.metamodel.JavaParserMetaModel;
import com.github.javaparser.metamodel.LambdaExprMetaModel;
import java.util.Optional;
import java.util.function.Consumer;
/**
* A lambda expression
* Java 1-7
* Does not exist.
* Java 8+
* {@code (a, b) -> a + b}
*
{@code a -> ...}
*
{@code (Long a) -> { println(a); }}
* The parameters are on the left side of the ->.
* If a parameter uses type inference (it has no type specified) then its type is set to {@code UnknownType}.
* If they are in ( ), "isEnclosingParameters" is true.
*
The body is to the right of the ->.
* The body is either a BlockStmt when it is in { } braces, or an ExpressionStmt when it is not in braces.
*
* @author Raquel Pau
*/
public class LambdaExpr extends Expression implements NodeWithParameters {
private NodeList parameters;
private boolean isEnclosingParameters;
private Statement body;
public LambdaExpr() {
this(null, new NodeList<>(), new ReturnStmt(), false);
}
/**
* Creates a single parameter lambda expression.
*/
public LambdaExpr(Parameter parameter, BlockStmt body) {
this(null, new NodeList<>(parameter), body, false);
}
/**
* Creates a zero or multi-parameter lambda expression with its parameters wrapped in ( ).
*/
public LambdaExpr(NodeList parameters, BlockStmt body) {
this(null, parameters, body, true);
}
/**
* Creates a single parameter lambda expression.
*/
public LambdaExpr(Parameter parameter, Expression body) {
this(null, new NodeList<>(parameter), new ExpressionStmt(body), false);
}
/**
* Creates a zero or multi-parameter lambda expression with its parameters wrapped in ( ).
*/
public LambdaExpr(NodeList parameters, Expression body) {
this(null, parameters, new ExpressionStmt(body), true);
}
@AllFieldsConstructor
public LambdaExpr(NodeList parameters, Statement body, boolean isEnclosingParameters) {
this(null, parameters, body, isEnclosingParameters);
}
/**
* This constructor is used by the parser and is considered private.
*/
@Generated("com.github.javaparser.generator.core.node.MainConstructorGenerator")
public LambdaExpr(
TokenRange tokenRange, NodeList parameters, Statement body, boolean isEnclosingParameters) {
super(tokenRange);
setParameters(parameters);
setBody(body);
setEnclosingParameters(isEnclosingParameters);
customInitialization();
}
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public NodeList getParameters() {
return parameters;
}
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public LambdaExpr setParameters(final NodeList parameters) {
assertNotNull(parameters);
if (parameters == this.parameters) {
return this;
}
notifyPropertyChange(ObservableProperty.PARAMETERS, this.parameters, parameters);
if (this.parameters != null) this.parameters.setParentNode(null);
this.parameters = parameters;
setAsParentNodeOf(parameters);
return this;
}
/**
* @return a BlockStatement or an ExpressionStatement. See class Javadoc.
*/
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public Statement getBody() {
return body;
}
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public LambdaExpr setBody(final Statement body) {
assertNotNull(body);
if (body == this.body) {
return this;
}
notifyPropertyChange(ObservableProperty.BODY, this.body, body);
if (this.body != null) this.body.setParentNode(null);
this.body = body;
setAsParentNodeOf(body);
return this;
}
@Override
@Generated("com.github.javaparser.generator.core.node.AcceptGenerator")
public R accept(final GenericVisitor v, final A arg) {
return v.visit(this, arg);
}
@Override
@Generated("com.github.javaparser.generator.core.node.AcceptGenerator")
public void accept(final VoidVisitor v, final A arg) {
v.visit(this, arg);
}
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public boolean isEnclosingParameters() {
return isEnclosingParameters;
}
@Generated("com.github.javaparser.generator.core.node.PropertyGenerator")
public LambdaExpr setEnclosingParameters(final boolean isEnclosingParameters) {
if (isEnclosingParameters == this.isEnclosingParameters) {
return this;
}
notifyPropertyChange(
ObservableProperty.ENCLOSING_PARAMETERS, this.isEnclosingParameters, isEnclosingParameters);
this.isEnclosingParameters = isEnclosingParameters;
return this;
}
@Override
@Generated("com.github.javaparser.generator.core.node.RemoveMethodGenerator")
public boolean remove(Node node) {
if (node == null) {
return false;
}
for (int i = 0; i < parameters.size(); i++) {
if (parameters.get(i) == node) {
parameters.remove(i);
return true;
}
}
return super.remove(node);
}
/**
* @return if the body of this lambda is a simple expression, return that expression.
* Otherwise (when the body is a block) return Optional.empty().
*/
@DerivedProperty
public Optional getExpressionBody() {
if (body.isExpressionStmt()) {
return Optional.of(body.asExpressionStmt().getExpression());
}
return Optional.empty();
}
@Override
@Generated("com.github.javaparser.generator.core.node.CloneGenerator")
public LambdaExpr clone() {
return (LambdaExpr) accept(new CloneVisitor(), null);
}
@Override
@Generated("com.github.javaparser.generator.core.node.GetMetaModelGenerator")
public LambdaExprMetaModel getMetaModel() {
return JavaParserMetaModel.lambdaExprMetaModel;
}
@Override
@Generated("com.github.javaparser.generator.core.node.ReplaceMethodGenerator")
public boolean replace(Node node, Node replacementNode) {
if (node == null) {
return false;
}
if (node == body) {
setBody((Statement) replacementNode);
return true;
}
for (int i = 0; i < parameters.size(); i++) {
if (parameters.get(i) == node) {
parameters.set(i, (Parameter) replacementNode);
return true;
}
}
return super.replace(node, replacementNode);
}
@Override
@Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")
public boolean isLambdaExpr() {
return true;
}
@Override
@Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")
public LambdaExpr asLambdaExpr() {
return this;
}
@Override
@Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")
public void ifLambdaExpr(Consumer action) {
action.accept(this);
}
@Override
@Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")
public Optional toLambdaExpr() {
return Optional.of(this);
}
/*
* Lambda expressions are always poly expressions
*/
@Override
public boolean isPolyExpression() {
return true;
}
/*
* Returns true if no type parameter has been defined
*/
public boolean isExplicitlyTyped() {
return getParameters().stream().allMatch(p -> !(p.getType().isUnknownType()));
}
}