jena-base/src/main/java/org/apache/jena/atlas/iterator/AccString.java

/*
 * 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.jena.atlas.iterator;

public class AccString<T> implements Accumulate<T, String>
{
    StringBuilder buffer = null ;
    private String sep ;
    private boolean first = true ;

    // Fresh StringBuilder
    public AccString(String sep) { this.sep = sep ; }
    public AccString() { this(" ") ; }

    @Override
    public void accumulate(T item)
    { 
        if ( ! first )
            buffer.append(sep) ;
        if ( item != null )
            buffer.append(toString(item)) ;
        else
            buffer.append("<null>") ;
        first = false ;
    }

    /** Make into a string */
    protected String toString(T item)
    {
        return item.toString() ; 
    }
    
    @Override
    public String get()
    {
        return buffer.toString() ;
    }

    @Override
    public void start()
    { 
        // Resets on each use.
        buffer = new StringBuilder() ; 
        first = true ;
    }
    
    @Override
    public void finish() {}

}