Java Collection to String collectionToString(final Collection<?> c)

Description

Converts a Collection into a String

License

Open Source License

Parameter

Parameter	Description
c	the Collection

Return

the String

Declaration

public final static String collectionToString(final Collection<?> c)

Method Source Code

//package com.java2s;
/**//  w  w w . j a  v  a2 s.c o m
 * The contents of this file are subject to the Regenstrief Public License
 * Version 1.0 (the "License"); you may not use this file except in compliance with the License.
 * Please contact Regenstrief Institute if you would like to obtain a copy of the license.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * Copyright (C) Regenstrief Institute.  All Rights Reserved.
 */

import java.util.*;

public class Main {
    /**
     * Converts a Collection into a String
     * 
     * @param c the Collection
     * @return the String
     **/
    public final static String collectionToString(final Collection<?> c) {
        final Iterator<?> iter = c == null ? null : c.iterator();

        if (!hasNext(iter)) {
            return null;
        }

        final StringBuilder sb = new StringBuilder();
        for (; iter.hasNext();) {
            final String s = toString(iter.next());
            if (s != null) {
                sb.append(s);
            }
            if (iter.hasNext()) {
                sb.append('\n');
            }
        }

        return sb.toString();
    }

    public final static <E> Iterator<E> iterator(final Iterable<E> iterable) {
        return iterable == null ? null : iterable.iterator();
    }

    public final static boolean hasNext(final Iterator<?> i) {
        return (i != null) && i.hasNext();
    }

    /**
     * Converts an object to a string
     * 
     * @param o the Object to convert
     * @return the String
     **/
    public final static String toString(final Object o) {
        return o == null ? null : o.toString();
    }

    /**
     * Appends the given character to the given StringBuffer, allocating the StringBuffer if
     * necessary
     * 
     * @param sb the StringBuffer
     * @param c the char
     * @return the StringBuffer
     **/
    public final static StringBuffer append(final StringBuffer sb, final char c) {
        return (sb == null ? new StringBuffer() : sb).append(c);
    }

    /**
     * Appends the given String to the given StringBuffer, allocating the StringBuffer if necessary
     * 
     * @param sb the StringBuffer
     * @param s the String
     * @return the StringBuffer
     **/
    public final static StringBuffer append(final StringBuffer sb, final String s) {
        return s == null ? sb : (sb == null ? new StringBuffer() : sb).append(s);
    }

    /**
     * Appends part of the given CharSequence to the given StringBuffer, allocating the StringBuffer
     * if necessary
     * 
     * @param sb the StringBuffer
     * @param s the String
     * @param offset the offset of the CharSequence at which to start copying
     * @param len the number of characters to copy
     * @return the StringBuffer
     **/
    public final static StringBuffer append(StringBuffer sb, final CharSequence s, int offset, int len) {
        if (sb == null) {
            sb = new StringBuffer(len);
        }
        sb.ensureCapacity(sb.length() + len);
        for (len += offset; offset < len; offset++) {
            sb.append(s.charAt(offset));
        }

        return sb;
    }

    /**
     * Appends the given character to the given StringBuilder, allocating the StringBuilder if
     * necessary
     * 
     * @param sb the StringBuilder
     * @param c the char
     * @return the StringBuilder
     **/
    public final static StringBuilder append(final StringBuilder sb, final char c) {
        return ((sb == null) ? new StringBuilder() : sb).append(c);
    }

    /**
     * Appends the given String to the given StringBuilder, allocating the StringBuilder if necessary
     * 
     * @param sb the StringBuilder
     * @param s the String
     * @return the StringBuilder
     **/
    public final static StringBuilder append(final StringBuilder sb, final String s) {
        return (s == null) ? sb : ((sb == null) ? new StringBuilder() : sb).append(s);
    }

    public final static <E> void ensureCapacity(final Collection<E> col, final int minCapacity) {
        if (col instanceof ArrayList) {
            ((ArrayList<E>) col).ensureCapacity(minCapacity);
        }
    }

    /**
     * Returns the length of the given array
     * 
     * @param array the array for which to return the length
     * @return the length
     **/
    public final static int length(final Object array) {
        if (array == null) {
            return 0;
        } else if (array instanceof byte[]) {
            return ((byte[]) array).length;
        } else if (array instanceof short[]) {
            return ((short[]) array).length;
        } else if (array instanceof int[]) {
            return ((int[]) array).length;
        } else if (array instanceof long[]) {
            return ((long[]) array).length;
        } else if (array instanceof float[]) {
            return ((float[]) array).length;
        } else if (array instanceof double[]) {
            return ((double[]) array).length;
        } else if (array instanceof boolean[]) {
            return ((boolean[]) array).length;
        } else if (array instanceof char[]) {
            return ((char[]) array).length;
        }
        return ((Object[]) array).length;
    }

    /**
     * Returns the length of the given array
     * 
     * @param array the array for which to return the length
     * @return the length
     **/
    public final static int length(final Object[] array) {
        return array == null ? 0 : array.length;
    }

    /**
     * Returns the length of the given array
     * 
     * @param array the array for which to return the length
     * @return the length
     **/
    public final static int length(final byte[] array) {
        return array == null ? 0 : array.length;
    }

    /**
     * Returns the length of the given array
     * 
     * @param array the array for which to return the length
     * @return the length
     **/
    public final static int length(final int[] array) {
        return array == null ? 0 : array.length;
    }

    /**
     * Retrieves the length of the CharSequence
     * 
     * @param s the CharSequence
     * @return the length
     **/
    public final static int length(final CharSequence s) {
        return s == null ? 0 : s.length();
    }
}

Java Collection to String collectionToString(final Collection c)

Description

License

Parameter

Return

Declaration

Method Source Code

Related