com.revolsys.ui.web.config.JavaComponent.java Source code

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Here is the source code for com.revolsys.ui.web.config.JavaComponent.java

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/*
 * Copyright 2004-2005 Revolution Systems Inc.
 *
 * 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 com.revolsys.ui.web.config;

import java.io.IOException;
import java.io.Writer;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.jsp.PageContext;

import org.apache.commons.jexl.Expression;
import org.apache.log4j.Logger;

import com.revolsys.util.JexlUtil;

public class JavaComponent extends Component {
    private static final Logger log = Logger.getLogger(JavaComponent.class);

    private static final Class[] SERIALIZE_METHOD_ARGS = new Class[] { Writer.class };

    private static final Class[] SET_PROPERTY_ARGS = new Class[] { String.class, Object.class };

    private String className;

    private Class componentClass;

    private final Map properties = new HashMap();

    private Method serializeMethod;

    private Method setPropertyMethod;

    public JavaComponent(final JavaComponent component) {
        super(component);
        setClassName(component.className);
        this.properties.putAll(component.properties);
    }

    public JavaComponent(final String area, final String name, final String className) {
        super(area, name);
        setClassName(className);
    }

    @Override
    public Object clone() {
        return new JavaComponent(this);
    }

    @Override
    public boolean equals(final Object o) {
        if (o instanceof JavaComponent) {
            final JavaComponent c = (JavaComponent) o;
            if (c.className.equals(this.className) && super.equals(o)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Generate the hash code for the object.
     *
     * @return The hashCode.
     */
    @Override
    public int hashCode() {
        return this.className.hashCode();
    }

    @Override
    public void includeComponent(final PageContext context) throws ServletException, IOException {
        Object instance;
        try {
            instance = this.componentClass.newInstance();
        } catch (final Exception e) {
            throw new ServletException("Unable to create component instance", e);
        }
        try {
            final Iterator propertyNames = this.properties.keySet().iterator();
            while (propertyNames.hasNext()) {
                final String propertyName = (String) propertyNames.next();
                Object value = this.properties.get(propertyName);
                final WebUiContext niceContext = WebUiContext.get();
                try {
                    final Expression expression = JexlUtil.newExpression(value.toString());
                    if (expression != null) {
                        value = niceContext.evaluateExpression(expression);
                    }
                } catch (final Exception e) {
                    throw new ServletException(e.getMessage(), e);
                }

                this.setPropertyMethod.invoke(instance, new Object[] { propertyName, value });
            }
        } catch (final IllegalAccessException e) {
            log.error("Unable to set component properties", e.getCause());
            throw new ServletException("Unable to set component properties", e);
        } catch (final InvocationTargetException e) {
            log.error("Unable to set component properties", e.getCause());
            throw new ServletException("Unable to set component properties", e.getCause());
        }
        try {
            final Writer out = context.getOut();
            this.serializeMethod.invoke(instance, new Object[] { out });
        } catch (final IllegalAccessException e) {
            throw new ServletException("Unable to serialize component", e);
        } catch (final InvocationTargetException e) {
            final Throwable cause = e.getCause();
            log.error(cause.getMessage(), cause);
            if (cause instanceof IOException) {
                throw (IOException) cause;
            }
            throw new ServletException("Unable to serialize component", cause);
        }
    }

    private void setClassName(final String className) {
        this.className = className;
        try {
            this.componentClass = Class.forName(className);
        } catch (final ClassNotFoundException e) {
            throw new IllegalArgumentException(e.getMessage());
        }
        try {
            this.setPropertyMethod = this.componentClass.getMethod("setProperty", SET_PROPERTY_ARGS);
        } catch (final NoSuchMethodException e) {
            throw new IllegalArgumentException("Class " + className
                    + " must have a method with the signature 'public void setProperty(String name, Object value)'");
        }
        try {
            this.serializeMethod = this.componentClass.getMethod("serialize", SERIALIZE_METHOD_ARGS);
        } catch (final NoSuchMethodException e) {
            throw new IllegalArgumentException("Class " + className
                    + " must have a method with the signature 'public void serialize(Writer out) throws IOException'");
        }
    }

    public void setProperty(final String name, final String value) {
        this.properties.put(name, value);
    }

    @Override
    public String toString() {
        final StringBuilder s = new StringBuilder(this.className).append("(");
        for (final Iterator props = this.properties.entrySet().iterator(); props.hasNext();) {
            final Map.Entry prop = (Map.Entry) props.next();
            s.append(prop.getKey()).append("=").append(prop.getValue());
            if (props.hasNext()) {
                s.append(",");
            }
        }
        s.append(")");
        return s.toString();
    }
}