ClassMethodInspector.java

/*
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * 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.kie.workbench.common.services.datamodel.backend.server.builder.projects;

import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.drools.workbench.models.datamodel.oracle.MethodInfo;
import org.kie.workbench.common.services.datamodel.backend.server.builder.util.BlackLists;

/**
 * Finds all methods that are not getters or setters from a class.
 */
public class ClassMethodInspector {

    private final Set<MethodInfo> methods = new HashSet<MethodInfo>();

    public ClassMethodInspector( final Class<?> clazz,
                                 final ClassToGenericClassConverter converter ) throws IOException {
        final Method[] methods = clazz.getDeclaredMethods();
        for ( int i = 0; i < methods.length; i++ ) {
            Method aMethod = methods[ i ];
            int modifiers = methods[ i ].getModifiers();
            String methodName = aMethod.getName();

            if ( isNotGetterOrSetter( aMethod ) && !BlackLists.isClassMethodBlackListed( clazz,
                                                                                         methodName ) && Modifier.isPublic( modifiers ) ) {

                Class<?>[] listParam = aMethod.getParameterTypes();

                MethodInfo info = new MethodInfo( methodName,
                                                  convertParameterTypes( converter,
                                                                         listParam ),
                                                  aMethod.getReturnType(),
                                                  obtainGenericType( aMethod.getGenericReturnType() ),
                                                  converter.translateClassToGenericType( aMethod.getReturnType() ) );
                this.methods.add( info );
            }
        }
    }

    /**
     * Translate Method Parameter types to the generic types used by DataModelOracle
     * @param converter
     * @param listParam
     * @return
     */
    private List<String> convertParameterTypes( final ClassToGenericClassConverter converter,
                                                final Class<?>[] listParam ) {
        List<String> params = new ArrayList<String>();

        if ( listParam.length == 0 ) {
            return params;
        } else {

            for ( int i = 0; i < listParam.length; i++ ) {
                final String type = converter.translateClassToGenericType( listParam[ i ] );
                params.add( type );
            }

            return params;
        }
    }

    /**
     * Check if this method is a mutator or accessor method for a field.
     * <p/>
     * If method starts with set or get and is longer than 3 characters.
     * For example java.util.List.set(int index, Object element) is considered to be a method, not a setter.
     * @param m
     */
    private boolean isNotGetterOrSetter( final Method m ) {
        return !( isSetter( m ) || isGetter( m ) || isBooleanGetter( m ) );
    }

    private boolean isSetter( final Method m ) {
        String name = m.getName();
        int parameterCount = m.getParameterTypes().length;
        if ( parameterCount != 1 ) {
            return false;
        }
        return ( name.length() > 3 && name.startsWith( "set" ) );
    }

    private boolean isGetter( final Method m ) {
        String name = m.getName();
        int parameterCount = m.getParameterTypes().length;
        if ( parameterCount != 0 ) {
            return false;
        }
        return ( name.length() > 3 && name.startsWith( "get" ) );
    }

    private boolean isBooleanGetter( final Method m ) {
        String name = m.getName();
        int parameterCount = m.getParameterTypes().length;
        if ( parameterCount != 0 ) {
            return false;
        }
        return ( name.length() > 2 && name.startsWith( "is" ) && ( Boolean.class.isAssignableFrom( m.getReturnType() ) || Boolean.TYPE == m.getReturnType() ) );
    }

    public List<String> getMethodNames() {
        List<String> methodList = new ArrayList<String>();
        for ( MethodInfo info : methods ) {
            methodList.add( info.getName() );
        }
        return methodList;
    }

    public List<MethodInfo> getMethodInfos() {
        return new ArrayList<MethodInfo>( this.methods );
    }

    private String obtainGenericType( final Type type ) {
        if ( type instanceof ParameterizedType ) {
            ParameterizedType pt = (ParameterizedType) type;
            Type goodType = null;
            for ( Type t : pt.getActualTypeArguments() ) {
                goodType = t;
            }
            if ( goodType != null ) {
                if ( goodType instanceof Class ) {
                    return ( (Class) goodType ).getName();
                }
                int index = goodType.toString().lastIndexOf( "." );
                return goodType.toString().substring( index + 1 );
            } else {
                return null;
            }
        }
        return null;
    }

}