Java Collection to String toString(Collection c)

Description

to String

License

Apache License

Declaration

public static String toString(Collection<?> c) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.util.Collection;
import java.util.Map;

public class Main {
    public static final String STRING_NULL = "<null>";
    public static final String STRING_TRUE = "<true>";
    public static final String STRING_FALSE = "<false>";
    public static final String STRING_SEQUENCE_SEPARATOR = ", ";
    public static final String STRING_KEY_VALUE_SEPARATOR = ": ";
    public static final String STRING_LIST_EMPTY = "[]";
    public static final String STRING_MAP_EMPTY = "{}";
    public static final char STRING_LIST_OPEN = '[';
    public static final char STRING_LIST_CLOSE = ']';
    public static final char STRING_MAP_OPEN = '{';
    public static final char STRING_MAP_CLOSE = '}';
    private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
            'e', 'f' };

    public static String toString(boolean v) {
        return v ? STRING_TRUE : STRING_FALSE;
    }//w w  w . j av  a 2 s . c  o  m

    public static String toString(byte v) {
        int i = v & 0xFF;
        return new String(new char[] { DIGITS[i >>> 4], DIGITS[i & 0x0F] });
    }

    public static String toString(char v) {
        return String.valueOf(v);
    }

    public static String toString(short v) {
        return String.valueOf(v);
    }

    public static String toString(int v) {
        return String.valueOf(v);
    }

    public static String toString(long v) {
        return String.valueOf(v);
    }

    public static String toString(float v) {
        return String.valueOf(v);
    }

    public static String toString(double v) {
        return String.valueOf(v);
    }

    public static String toString(Object v) {
        if (v == null) {
            return STRING_NULL;
        }

        if (v instanceof Boolean) {
            return toString(((Boolean) v).booleanValue());
        }
        if (v instanceof Byte) {
            return toString(((Byte) v).byteValue());
        }
        if (v instanceof Character) {
            return toString(((Character) v).charValue());
        }
        if (v instanceof Short) {
            return toString(((Short) v).shortValue());
        }
        if (v instanceof Integer) {
            return toString(((Integer) v).intValue());
        }
        if (v instanceof Long) {
            return toString(((Long) v).longValue());
        }
        if (v instanceof Float) {
            return toString(((Float) v).floatValue());
        }
        if (v instanceof Double) {
            return toString(((Double) v).doubleValue());
        }

        if (v instanceof Collection) {
            return toString((Collection) v);
        }

        if (v instanceof Map) {
            return toString((Map) v);
        }

        if (v instanceof boolean[]) {
            return toString((boolean[]) v);
        }
        if (v instanceof byte[]) {
            return toString((byte[]) v);
        }
        if (v instanceof char[]) {
            return toString((char[]) v);
        }
        if (v instanceof short[]) {
            return toString((short[]) v);
        }
        if (v instanceof int[]) {
            return toString((int[]) v);
        }
        if (v instanceof long[]) {
            return toString((long[]) v);
        }
        if (v instanceof float[]) {
            return toString((float[]) v);
        }
        if (v instanceof double[]) {
            return toString((double[]) v);
        }

        if (v.getClass().isArray()) {
            return toString((Object[]) v);
        }

        return v.toString();
    }

    public static String toString(boolean[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(9 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (boolean v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(byte[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (byte v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            int i = v & 0xFF;
            string.append(DIGITS[i >>> 4]).append(DIGITS[i & 0x0F]);
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(char[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(3 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (char v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(short[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (short v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(int[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (int v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(long[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (long v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(float[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (float v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(double[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (double v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(Object[] a) {
        if (a == null) {
            return STRING_NULL;
        }
        if (a.length == 0) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * a.length);
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (Object v : a) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(Collection<?> c) {
        if (c == null) {
            return STRING_NULL;
        }
        if (c.isEmpty()) {
            return STRING_LIST_EMPTY;
        }

        StringBuilder string = new StringBuilder(4 * c.size());
        boolean sep = false;
        string.append(STRING_LIST_OPEN);
        for (Object v : c) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(v));
        }
        return string.append(STRING_LIST_CLOSE).toString();
    }

    public static String toString(Map<?, ?> m) {
        if (m == null) {
            return STRING_NULL;
        }
        if (m.isEmpty()) {
            return STRING_MAP_EMPTY;
        }

        StringBuilder string = new StringBuilder(6 * m.size());
        boolean sep = false;
        string.append(STRING_MAP_OPEN);

        for (Map.Entry<?, ?> e : m.entrySet()) {
            if (sep) {
                string.append(STRING_SEQUENCE_SEPARATOR);
            } else {
                sep = true;
            }
            string.append(toString(e.getKey())).append(STRING_KEY_VALUE_SEPARATOR).append(toString(e.getValue()));
        }
        return string.append(STRING_MAP_CLOSE).toString();
    }

    public static void toString(StringBuilder builder, boolean v) {
        builder.append(v ? STRING_TRUE : STRING_FALSE);
    }

    public static void toString(StringBuilder builder, byte v) {
        int i = v & 0xFF;
        builder.ensureCapacity(builder.capacity() + 2);
        builder.append(DIGITS[i >>> 4]).append(DIGITS[i & 0x0F]);
    }

    public static void toString(StringBuilder builder, char v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, short v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, int v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, long v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, float v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, double v) {
        builder.append(v);
    }

    public static void toString(StringBuilder builder, Object v) {
        if (v == null) {
            builder.append(STRING_NULL);
        } else if (v instanceof Boolean) {
            toString(builder, ((Boolean) v).booleanValue());
        } else if (v instanceof Byte) {
            toString(builder, ((Byte) v).byteValue());
        } else if (v instanceof Character) {
            toString(builder, ((Character) v).charValue());
        } else if (v instanceof Short) {
            toString(builder, ((Short) v).shortValue());
        } else if (v instanceof Integer) {
            toString(builder, ((Integer) v).intValue());
        } else if (v instanceof Long) {
            toString(builder, ((Long) v).longValue());
        } else if (v instanceof Float) {
            toString(builder, ((Float) v).floatValue());
        } else if (v instanceof Double) {
            toString(builder, ((Double) v).doubleValue());
        }

        else if (v instanceof Collection) {
            toString(builder, (Collection) v);
        }

        else if (v instanceof Map) {
            toString(builder, (Map) v);
        }

        else if (v instanceof boolean[]) {
            toString(builder, (boolean[]) v);
        } else if (v instanceof byte[]) {
            toString(builder, (byte[]) v);
        } else if (v instanceof char[]) {
            toString(builder, (char[]) v);
        } else if (v instanceof short[]) {
            toString(builder, (short[]) v);
        } else if (v instanceof int[]) {
            toString(builder, (int[]) v);
        } else if (v instanceof long[]) {
            toString(builder, (long[]) v);
        } else if (v instanceof float[]) {
            toString(builder, (float[]) v);
        } else if (v instanceof double[]) {
            toString(builder, (double[]) v);
        }

        else if (v.getClass().isArray()) {
            toString(builder, (Object[]) v);
        }

        else {
            builder.append(v.toString());
        }
    }

    public static void toString(StringBuilder builder, boolean[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 9 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (boolean v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                toString(builder, v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, byte[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (byte v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                int i = v & 0xFF;
                builder.append(DIGITS[i >>> 4]).append(DIGITS[i & 0x0F]);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, char[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 3 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (char v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, short[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (short v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, int[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (int v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, long[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (long v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, float[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (float v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, double[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (double v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                builder.append(v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, Object[] a) {
        if (a == null) {
            builder.append(STRING_NULL);
        } else if (a.length == 0) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * a.length);
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (Object v : a) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                toString(builder, v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, Collection<?> c) {
        if (c == null) {
            builder.append(STRING_NULL);
        } else if (c.isEmpty()) {
            builder.append(STRING_LIST_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 4 * c.size());
            builder.append(STRING_LIST_OPEN);
            boolean sep = false;
            for (Object v : c) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                toString(builder, v);
            }

            builder.append(STRING_LIST_CLOSE);
        }
    }

    public static void toString(StringBuilder builder, Map<?, ?> m) {
        if (m == null) {
            builder.append(STRING_NULL);
        } else if (m.isEmpty()) {
            builder.append(STRING_MAP_EMPTY);
        } else {
            builder.ensureCapacity(builder.capacity() + 6 * m.size());
            builder.append(STRING_MAP_OPEN);
            boolean sep = false;
            for (Map.Entry<?, ?> e : m.entrySet()) {
                if (sep) {
                    builder.append(STRING_SEQUENCE_SEPARATOR);
                } else {
                    sep = true;
                }
                toString(builder, e.getKey());
                builder.append(STRING_KEY_VALUE_SEPARATOR);
                toString(builder, e.getValue());
            }
            builder.append(STRING_MAP_CLOSE);
        }
    }
}

Related

1. toString(Collection setOfTests)
2. toString(Collection softwareTags)
3. toString(Collection collection)
4. toString(Collection collection, String prefix, String suffix)
5. toString(Collection c)
6. toString(Collection collection)
7. toString(Collection collection)
8. toString(Collection collection)
9. toString(Collection collection, String separator)