/*
 *  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.
 */
package org.apache.groovy.parser.antlr4;

import org.codehaus.groovy.ast.ModuleNode;
import org.codehaus.groovy.control.CompilationFailedException;
import org.codehaus.groovy.control.ParserPlugin;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.syntax.ParserException;
import org.codehaus.groovy.syntax.Reduction;

import java.io.IOException;

/**
 * A parser plugin for the new parser
 *
 * @author  <a href="mailto:realbluesun@hotmail.com">Daniel.Sun</a>
 * Created on    2016/08/14
 */
public class Antlr4ParserPlugin implements ParserPlugin {
    private ModuleNode moduleNode;

    @Override
    public Reduction parseCST(SourceUnit sourceUnit, java.io.Reader reader) throws CompilationFailedException {
        return null;
    }

    @Override
    public ModuleNode buildAST(SourceUnit sourceUnit, java.lang.ClassLoader classLoader, Reduction cst) throws ParserException {
        if (null != this.moduleNode) {
            return this.moduleNode;
        }

        AstBuilder builder = new AstBuilder(sourceUnit, classLoader);
        this.moduleNode = builder.buildAST();

        return this.moduleNode;
    }
}

/*
 *  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.
 */
package org.apache.groovy.parser.antlr4;

import org.codehaus.groovy.ast.ModuleNode;
import org.codehaus.groovy.control.CompilationFailedException;
import org.codehaus.groovy.control.ParserPlugin;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.syntax.ParserException;
import org.codehaus.groovy.syntax.Reduction;

/**
 * A parser plugin for the new parser
 *
 * @author  <a href="mailto:realbluesun@hotmail.com">Daniel.Sun</a>
 * Created on    2016/08/14
 */
public class Antlr4ParserPlugin implements ParserPlugin {
    private ModuleNode moduleNode;

    @Override
    public Reduction parseCST(SourceUnit sourceUnit, java.io.Reader reader) throws CompilationFailedException {
        return null;
    }

    @Override
    public ModuleNode buildAST(SourceUnit sourceUnit, java.lang.ClassLoader classLoader, Reduction cst) throws ParserException {
        if (null != this.moduleNode) {
            return this.moduleNode;
        }

        AstBuilder builder = new AstBuilder(sourceUnit, classLoader);
        this.moduleNode = builder.buildAST();

        return this.moduleNode;
    }
}

Remove unused imports