tapestry/tapestry-framework/src/java/org/apache/tapestry/enhance/InjectMetaWorker.java

// Copyright 2005 The Apache Software Foundation
//
// 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.apache.tapestry.enhance;

import org.apache.hivemind.Location;
import org.apache.hivemind.service.BodyBuilder;
import org.apache.hivemind.service.ClassFabUtils;
import org.apache.hivemind.service.MethodSignature;
import org.apache.hivemind.util.Defense;
import org.apache.tapestry.coerce.ValueConverter;
import org.apache.tapestry.services.ComponentPropertySource;
import org.apache.tapestry.spec.InjectSpecification;

import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;

/**
 * Injects meta data obtained via {@link org.apache.tapestry.services.ComponentPropertySource}
 * (meaning that meta-data is searched for in the component's specification, then it's namespace
 * (library or application specification), then the global application properties.
 *
 * @author Howard M. Lewis Ship
 * @since 4.0
 */
public class InjectMetaWorker implements InjectEnhancementWorker
{
    static final String SOURCE_NAME = "_$componentPropertySource";

    private ComponentPropertySource _source;

    private ValueConverter _valueConverter;

    private Map _primitiveParser = new HashMap();
    {
        _primitiveParser.put(short.class, "java.lang.Short.parseShort");
        _primitiveParser.put(int.class, "java.lang.Integer.parseInt");
        _primitiveParser.put(long.class, "java.lang.Long.parseLong");
        _primitiveParser.put(double.class, "java.lang.Double.parseDouble");
        _primitiveParser.put(float.class, "java.lang.Float.parseFloat");
    }

    public void performEnhancement(EnhancementOperation op, InjectSpecification spec)
    {
        String propertyName = spec.getProperty();
        String metaKey = spec.getObject();

        injectMetaValue(op, propertyName, metaKey, spec.getLocation());
    }

    public void injectMetaValue(EnhancementOperation op, String propertyName, String metaKey,
                                Location location)
    {
        Defense.notNull(op, "op");
        Defense.notNull(propertyName, "propertyName");
        Defense.notNull(metaKey, "metaKey");

        Class propertyType = op.getPropertyType(propertyName);

        // Default to object if not specified

        if (propertyType == null) {

            propertyType = Object.class;
        }

        op.claimReadonlyProperty(propertyName);

        String sourceName = op.addInjectedField(SOURCE_NAME, ComponentPropertySource.class, _source);

        MethodSignature sig = new MethodSignature(propertyType, op.getAccessorMethodName(propertyName), null, null);

        String parser = (String) _primitiveParser.get(propertyType);

        if (parser != null)
        {
            addPrimitive(op, metaKey, propertyName, sig, sourceName, parser, location);
            return;
        } else if (propertyType == boolean.class)
        {
            addBoolean(op, metaKey, propertyName, sig, sourceName, location);
            return;
        }

        if (propertyType == char.class)
        {
            addCharacterPrimitive(op, metaKey, propertyName, sig, sourceName, location);
            return;
        }

        addObject(op, metaKey, propertyName, propertyType, sig, sourceName, location);
    }

    private void addPrimitive(EnhancementOperation op, String metaKey, String propertyName,
                              MethodSignature sig, String sourceName, String parser, Location location)
    {
        BodyBuilder builder = new BodyBuilder();
        builder.begin();
        builder.addln("java.lang.String meta = {0}.getComponentProperty(this, \"{1}\");",
                      sourceName,
                      metaKey);
        builder.addln("return {0}(meta);", parser);
        builder.end();

        op.addMethod(Modifier.PUBLIC, sig, builder.toString(), location);
    }

    private void addBoolean(EnhancementOperation op, String metaKey, String propertyName,
                            MethodSignature sig, String sourceName, Location location)
    {
        BodyBuilder builder = new BodyBuilder();
        builder.begin();
        builder.addln(
          "java.lang.String meta = {0}.getComponentProperty(this, \"{1}\");",
          sourceName,
          metaKey);
        builder.addln("return java.lang.Boolean.valueOf(meta).booleanValue();");
        builder.end();

        op.addMethod(Modifier.PUBLIC, sig, builder.toString(), location);
    }

    private void addCharacterPrimitive(EnhancementOperation op, String metaKey,
                                       String propertyName, MethodSignature sig, String sourceName, Location location)
    {
        BodyBuilder builder = new BodyBuilder();
        builder.begin();
        builder.addln(
          "java.lang.String meta = {0}.getComponentProperty(this, \"{1}\");",
          sourceName,
          metaKey);
        builder.addln("return meta.charAt(0);");
        builder.end();

        op.addMethod(Modifier.PUBLIC, sig, builder.toString(), location);
    }

    private void addObject(EnhancementOperation op, String metaKey, String propertyName,
                           Class propertyType, MethodSignature sig, String sourceName, Location location)
    {
        String valueConverterName = op.addInjectedField("_$valueConverter", ValueConverter.class, _valueConverter);

        String classRef = op.getClassReference(propertyType);

        BodyBuilder builder = new BodyBuilder();
        builder.begin();
        builder.addln("java.lang.String meta = {0}.getComponentProperty(this, \"{1}\");",
                      sourceName,
                      metaKey);
        builder.addln("return ({0}) {1}.coerceValue(meta, {2});", ClassFabUtils
          .getJavaClassName(propertyType), valueConverterName, classRef);
        builder.end();

        op.addMethod(Modifier.PUBLIC, sig, builder.toString(), location);
    }

    public void setSource(ComponentPropertySource source)
    {
        _source = source;
    }

    public void setValueConverter(ValueConverter valueConverter)
    {
        _valueConverter = valueConverter;
    }
}