com.feilong.taglib.functions.ELFunctions.java Source code

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Here is the source code for com.feilong.taglib.functions.ELFunctions.java

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/*
 * Copyright (C) 2008 feilong
 *
 * 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.feilong.taglib.functions;

import static org.apache.commons.lang3.StringUtils.EMPTY;

import java.util.Iterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.feilong.core.bean.ConvertUtil;
import com.feilong.taglib.common.AbstractContainsSupport;
import com.feilong.tools.jsonlib.JsonUtil;

/**
 * Static methods for JSP EL expression functions.
 * 
 * <h3>does-el-support-overloaded-methods?</h3>
 * 
 * <blockquote>
 * <p>
 * It'll always be the first method of the{@link Class#getMethods()}array whose name (and amount of arguments) matches the EL method call.
 * Whether it returns the same method everytime or not depends on the JVM make/version used.
 * </p>
 * 
 * <p>
 * Perhaps you made a Java SE upgrade in the meanwhile as well. The javadoc even says this:
 * </p>
 * 
 * <p style="color:green">
 * The elements in the array returned are not sorted and are not in any particular order.
 * </p>
 * 
 * <p>
 * You should not rely on unspecified behaviour. Give them a different name.
 * </p>
 * 
 * </blockquote>
 *
 * @author <a href="http://feitianbenyue.iteye.com/">feilong</a>
 * @see org.apache.taglibs.standard.functions.Functions
 * @see "org.owasp.esapi.tags.ELEncodeFunctions"
 * 
 * @see <a href="http://stackoverflow.com/questions/9763619/does-el-support-overloaded-methods">does-el-support-overloaded-methods</a>
 * @since 1.4.0
 */
public final class ELFunctions {

    /** The Constant log. */
    private static final Logger LOGGER = LoggerFactory.getLogger(ELFunctions.class);

    /** Don't let anyone instantiate this class. */
    private ELFunctions() {
        //AssertionError?. ?????. ???.
        //see Effective Java 2nd
        throw new AssertionError("No " + getClass().getName() + " instances for you!");
    }

    /**
     *  / el.
     * 
     * <p style="color:red">
     * ?, {@link java.lang.Object#toString()}
     * </p>
     * 
     * @param collection
     *            ?,?Iterator,??,?Iterator.
     * @param value
     *            ?,toString .
     * @return true, if successful
     * @see ConvertUtil#toIterator(Object)
     * @see org.apache.taglibs.standard.tag.common.core.ForEachSupport#supportedTypeForEachIterator(Object)
     */
    public static boolean contains(Object collection, Object value) {
        Iterator<?> iterator = ConvertUtil.toIterator(collection);
        return AbstractContainsSupport.containsByStringValue(iterator, value);
    }

    /**
     * format?json(?pretty,).
     *
     * @param obj
     *            the obj
     * @return the string
     * @see com.feilong.tools.jsonlib.JsonUtil#format(Object, int, int)
     */
    public static String toJsonString(Object obj) {
        try {
            return JsonUtil.format(obj, 0, 0);
        } catch (Exception e) {
            LOGGER.error("json format:" + obj.toString(), e);
        }
        //jsp,,????, ??, ,,null
        return EMPTY;
    }
}