TablePrinter.java

/*
 * © Copyright IBM Corp. 2012-2013
 * 
 * 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.ibm.commons.util.print;

import java.io.PrintStream;
import java.util.Iterator;

import com.ibm.commons.util.EmptyIterator;
import com.ibm.commons.util.FastStringBuffer;
import com.ibm.commons.util.StringUtil;
import com.ibm.commons.util.TDiag;

/**
 * @ibm-not-published 
 */
public class TablePrinter {
	
	public interface ITable {
		// Column Access
		public int getColumnCount() throws Exception;
		public String getColumnTitle(int col) throws Exception;
		public int getColumnSize(int col) throws Exception;
		
		// Row Access
		public Iterator getRows(int start, int count) throws Exception;
	}
	public interface IRow {
		public String getRowValue(int col) throws Exception;
	}

	private PrintStream ps;
	private ITable table;
	
	public TablePrinter() {
	}
	
	public TablePrinter(ITable table) {
		this.table = table;
	}
	
	
	public void println(String s) {
		getOutputStream().println(s);
	}

	public PrintStream getPrintStream() {
		return ps;
	}

	public void setPrintStream(PrintStream ps) {
		this.ps = ps;
	}
	
	public PrintStream getOutputStream() {
		return ps!=null ? ps : System.out;
	}
	
	public int getMaxColSize() {
		return 128;
	}
	
	public ITable getTable() {
		return table;
	}
	public void setTable(ITable table) {
		this.table = table;
	}
	public int print() {
		return print(0,Integer.MAX_VALUE);
	}
	
	public int print(int start, int c) {
		boolean printIfEmpty = true;
        try {
        	Iterator it = table!=null ? table.getRows(start, c) : EmptyIterator.getInstance();
        	if(it.hasNext() || printIfEmpty) {
                prtSeparator();
                prtHeader();
                prtSeparator();
        	}

        	int rowCount = 0;
            while(rowCount<c && it.hasNext()) {
            	IRow row = (IRow)it.next();
                prtRow(row);
                rowCount++;
            }

            if( rowCount>0 || printIfEmpty ) {
                prtSeparator();
            }
            return rowCount;
        } catch( Exception e ) {
            TDiag.exception(e);
        }
        return 0;
    }

    private void prtSeparator() throws Exception {
        FastStringBuffer b = new FastStringBuffer();
        int colCount = table.getColumnCount();
        for( int i=0; i<colCount; i++ ) {
            int sz = Math.min(table.getColumnSize(i),getMaxColSize());
            b.append( '+' );
            b.repeat( '-', sz );
        }
        b.append( '+' );
        println( b.toString() );
    }
    private void prtHeader() throws Exception {
        FastStringBuffer b = new FastStringBuffer();
        int colCount = table.getColumnCount();
        for( int i=0; i<colCount; i++ ) {
            int sz = Math.min(table.getColumnSize(i),getMaxColSize());
            b.append( '|' );
            b.append( pad(table.getColumnTitle(i), sz) );
        }
        b.append( '|' );
        println( b.toString() );
    }
    private void prtRow( IRow row ) throws Exception {
        FastStringBuffer b = new FastStringBuffer();
        int colCount = table.getColumnCount();
        for( int i=0; i<colCount; i++ ) {
            int sz = Math.min(table.getColumnSize(i),getMaxColSize());
            b.append( '|' );
            b.append( pad(colString(row,i), sz) );
        }
        b.append( '|' );
        println( b.toString() );
    }
    private String colString( IRow row, int col ) throws Exception {
        return row.getRowValue(col);
    }

    private static String pad( String s, int sz ) {
        if( s!=null ) {
            int strLen = s.length();
            if( strLen==sz ) {
                return s;
            }
            if( strLen>sz ) {
                return s.substring(0,sz);
            }
            return s + StringUtil.repeat( ' ', sz-strLen );
        } else {
            return StringUtil.repeat( ' ', sz );
        }
    }
}